Preventing Spread
of
Severe Acute
Respiratory Syndrome (SARS)
A World Health
Organization and
Centers for Disease
Control and Prevention
Satellite Broadcast
and Webcast
Transcript
JULIE LOUISE GERBERDING, MD, MPH:
Hello. I’m Dr. Julie Louise
Gerberding, Director of the Centers for Disease Control and Prevention. Thank you for joining us today for this
important program.
We are here today to give you an
update on the evolving investigation of SARS, the Severe Acute Respiratory
Syndrome that has been an emerging global problem over the last several
weeks.
In collaboration with the World Health
Organization, CDC and other international colleagues are continuing to
investigate and implement measures to control the expanding SARS outbreak. We are working to understand the modes of spread, the causes of illness, and what really is the best
way to prevent spread and treat patients with SARS.
Of course, our greatest concern is for
the patients, family members, and care providers who are suffering from this
illness or worried about this illness.
We extend our sympathy to you in this difficult time. We are encouraged that many SARS patients are
improving over time.
We continue to regard a previously
unrecognized Coronavirus as the leading hypothesis
for the etiology of this condition.
Laboratory evidence is mounting from a number of international
laboratories that this is indeed the case.
Laboratory investigators in many countries continue to explore Coronavirus as well as other potential viruses as the cause
of SARS. We will update these findings
as we go forward on this scientific investigation.
We are at a point in time where we
recognize that the disease is still primarily limited to those who have had
close contact with SARS patients. This
includes health care personnel who have taken care of SARS patients, household
contacts, and travelers to affected areas.
We believe, based on what the
investigations have shown us so far, that the major mode of transmission still
is through droplet spread when an infected person coughs or sneezes and
droplets are spread to a nearby contact. But we are concerned about the
possibility of airborne transmission across broader areas and also the
possibility that objects that could become contaminated in the environment
could serve as modes of spread.
Today you will hear from investigators
at WHO and CDC, as well as clinicians who have been involved in the affected
areas of
As we learn more or we learn something
different as we go forward in the investigation, our guidance will be updated.
Please check both the WHO and CDC websites for the latest information.
We thank you for taking the time to
view this program. Please know we are
doing everything we can to solve the mysteries of this epidemic and limit its
spread.
MODERATOR:
Thank you
Dr. Gerberding. Hello, I'm Kysa Daniels. Welcome to “Preventing Spread of Severe Acute
Respiratory Syndrome (SARS)”. We're
coming to you live from the Centers for Disease Control and Prevention in
At the end
of this program you should be able to describe the current outbreak of SARS, describe
strategies to prevent transmission in hospitals and healthcare facilities, and recognize
the need for international cooperation to stop the spread of SARS. We will not conduct any live on air question
and answer period during today's program, but you are encouraged to review the
WHO and CDC web site for all available information and updates.
The web
address for the World Health Organization is www.who.int.
The web address for the CDC is www.cdc.gov.
Viewers are
encouraged, but not required to register and evaluate the program on the CDC Training
and Continuing Education Online System. That
address is www.phppo.CDC.gov/phtnonline. A certificate of attendance will be awarded
to participants who complete the evaluation. Although continuing education
credit is not available for the broadcast or webcast,
registration and evaluation, however, will provide valuable feedback to CDC. Participants
will have about a month, until
register and evaluate the program. The course numbers are SB0128 for the
satellite broadcast and WC0028 for the webcast.
Questions
about registration should be directed to 800-41-train or 404-639-1292, or you
can e-mail your questions to
ce@CDC.gov.
When e-mailing a request, please indicate SARS and the
subject line. Now I'd like to introduce
the
first of two guests who will be coming to us from the World
Health Organization
headquarters in
Dr. David Heymann is Executive Director of Communicable
Diseases for
WHO. He will discuss SARS, a previously unrecognized
emerging disease. He will review the importance of SARS in terms of global health
and its impact on healthcare systems.
Dr. Heymann.
DAVID HEYMANN, MD:
Thank you, Kysa. During the past few weeks, the world has come to know
a newly identified infection in humans known as “severe acute respiratory syndrome,”
now commonly called SARS. This disease
occurs at a time of heightened surveillance in the world for influenza, because
on the 17th of February in
So, in this
environment with heightened surveillance, we responded to the unexpected. The
first slide shows you how the World Health Organization has a framework in
which it can respond to an unexpected infectious disease. At the top of the screen are the
international health regulations which have been agreed on by our 192 member states.
The regulations provide the mandate for global surveillance or global alert and
response. Under the regulations we work
with known risks such as influenza, with unexpected events such as what has happened
in the last few weeks, and at the same time, we have a part in increasing
preparedness, setting out norms and standards for countries in their surveillance
and response activities.
These
international health regulations helped us as we
first described on the 26th of February in
disease. This was a disease which
we heard was influenza because it was a very severe disease which had occurred
in a 48-year-old businessman who came to
This man
developed a high fever that rapidly progressed to an atypical pneumonia and
acute respiratory failure requiring ventilation. In Vietnam, there is a WHO office, as in most
developing countries, and the epidemiologist raised the alarm after he had seen
this case of atypical pneumonia and had seen health workers who became sick
from what he presumed was the same infection.
He alerted WHO at that time. In our alert at WHO, we take intelligence
such as we got from Dr. Urbani, and then verify that information.
We respond
as necessary to that information and, in this case, the country of
At the same
time, a similar disease occurred in
and outbreaks occurred in many different hospitals. There are now ten hospitals affected in
On the 11th
of March, we mapped out what was going on with this disease in the various
sites, and on the 12th, we put out a global alert, a moderate alert,
about this disease to different countries, describing what was occurring in the
countries. This press release was picked
up by ministers of health throughout the world and then, on the 14th of March,
we received a report from
When we had
that report on the 14th of March, we put it into our system of analysis and
decision making and decided that this looked to be an infectious agent and
possibly a new agent which at that time was affecting mostly health workers. It was an infection which could place a
burden on healthcare systems, and because there was a possibility that this
could become pandemic worldwide, we became alarmed. We had seen it travel out of
So, we had
in place at that time a global system which provided a case definition, asked countries
to report if they had this disease, and helped to make sure that the disease
did not travel further internationally.
We believe that this system was quite effective in working on describing
the epidemic to the world and also in stopping the spread of this disease
within countries to which it was imported.
We believe
that through this alert, the 18 countries who now have this virus and those to
whom it may spread will be able to contain the outbreak.
MODERATOR:
Thank you,
Dr. Heymann, you've just shared with us, of
course, the importance of countries working together to
halt this outbreak and certainly we all understand that we are still
in the midst of this problem and tracking its developments as we speak. For the remainder of this program we will
hear from speakers from WHO,
CDC who
will describe the current status of the investigation and some recommended
measures to stop the spread of SARS.
Right now,
though, we want to return to
JULIE
HALL, MD:
Thank you, Kysa. Dr. Heymann ran through some of the responses and the work that's
been going on over the past few weeks.
To recap and give more information on what has been happening, WHO in
collaboration with the Global
Alert and
Response Network, a partnership network of over 150 different institutions throughout
the world, has mounted an unprecedented global response to the threat of SARS. This response has taken place in six
different areas, epidemiology, laboratory, clinical, logistics, field teams and
the production of guidance and policy materials.
In terms of
epidemiology, global surveillance is now in place and reporting of cases, probable
and suspect cases to WHO is now taking place.
We're also
developing a system of collecting more data on
individual patients from affected countries so that better global analysis
of this problem can take place. It's a
collaborative network of epidemiologists of both affected and non-affected
countries around the world working on key issues such as transmission,
incubation period and other things that we desperately need to know more about
in terms of this disease. I'll be talking later in more detail about what we
know about the global epidemiology to date.
Secondary
response has been around laboratories. Twelve
laboratories in ten different countries from around the world have collaborated
to try and identify the causes of agents and Dr. Hughes will be talking later
about the work to date. This
collaboration of the 12 laboratories has meant that data and findings can be
shared at a very early stage and diagnostic testing are
now under way.
The third
area of collaboration that has taken place is around clinical findings and is
now a network of clinicians from around the world, particularly in those
countries which have been affected by SARS, that are working together to be
able to produce more detailed information about the clinical syndrome that is SARS
and about treatments that have been tried and what has been effective and Dr.
Sung will be talking about this later as well.
In terms of logistics, bases that are being established in
These
policies are because of the case definition, surveillance and reporting
procedures as well as guidance on case management, and infection control,
particularly within the hospital sector.
In addition to that, as Dr. Heymann mentioned,
travel advice, advice to travelers about the awareness of symptoms, as well as
advice to airlines
and other travel companies has been provided so that passengers can
be screened and advice given to those countries if someone falls ill.
In terms of
global epidemiology I'll just outline briefly the finding to date. To date, there are over 2,000 probable cases
of SARS that have been reported worldwide and over 60 deaths have occurred. The
majority of cases of SARS have occurred in the 30 to 50-year-old age group.
This is
probably reflective of the fact that the majority of cases have been health
care workers. There have been very few children reported as having SARS to
date, however in the last week or so, the children under the age of 16 with SARS
has increased. We've seen three
generations now of infection and transmission of SARS. The first generation and first wave of infections
in index cases, second wave being health care workers and close contact of the index
case and in some areas we are also seeing a third wave of transmission to
family members of healthcare workers. In
Data to
date collected from around the world shows that the
attack rates for this disease in hospitals where infection control procedures
are not in place can be greater than 50%, highlighting the real need for infection
control.
The
incubation period of SARS ranges from two to seven days
although
there have been reports of much shorter incubation periods of one day and a
longer incubation period of up to ten days. The mode of transmission of SARS has
yet to be fully explained. The major
reason appears to be very close contact and other roots of transmission still
have to be investigated further. Mortality
rate of SARS globally is running at about 4% and the majority
of those people who have died of SARS have been over the age of 14 and have had
other underlying conditions, however the numbers are very small and one must be
cautious in trying to interpret this information at the moment. So in summary, SARS is an important disease.
Global
surveillance is detected at a very early rate and global reporting has shown
that numbers are increasing globally. In
the majority of countries, after the global alerts have taken place, there have
been no further transmission of imported cases that have
taken place. That is all from me and so
back to
MODERATOR:
Thank you,
Dr. Julie Hall, from
and Chief of Medicine and Therapeutics at the Prince of
patients in
JOSEPH JY
SUNG, MD:
Following
is my report of the outbreak of SARS in
On March 10,
we found 18 health care workers in the hospital reported sick. On the next day, we actually found 50 of them
reported to have fever, rigors and chills.
When we screened them, we admitted 23 of them who were found to have
chest x-ray changes. Up to March 25th at
the Prince of Wales Hospital, we admitted up to 156 patients. including 130 cases
with direct or indirect contact with our index case.
The picture
shows the index patient who is a 26-year-old male with pneumonia, and a history
of traveling in
Demography
shows that out of the 138 cases, there were 72 females Sixty-nine of them were
health care workers, including 20 doctors, 34 nurses and 15 allied health workers.
We had 16 medical students doing a clinical examination on that day, and they
all got the disease. Nineteen patients staying in the same ward were also
affected.
This cohort
showed the common symptoms of SARS: Everybody had fever and rigors, and chills
were reported in over 70% of the cases, myalgia in
60%, and dry cough was reported in over 50% of the cases. We also had 40% of the
cases complaining of dizziness. Less
common symptoms included sore throat, runny nose, sputum production, nausea and
diarrhea. A white cell count lower than
3.5% was found in 34% of our cases, and, as you can see from the graph here,
the white cell count dropped as the disease progressed. We also found lymphopenia
as a predominant feature of this disease. Many patients had a low white cell
count which continues to drop as the disease became more severe, and all
together we had about 70% of patients with a lymphocyte count that dropped
below 1,000. We also found a low platelet
count as a very common feature in the blood count. Thrombocytopenia was reported in 44.8% of our
patients and the platelet count also continued to drop.
The
clotting profile of the patients was also deranged.
We found a
prolonged APTT, defined as longer than 38 seconds in 42.8% of the patients. Elevated D-Dimer
was also reported in nearly half of our patients, and actually, in two patients,
we had profound DIC documented. The serum
chemistry shown here indicates 23% of the patients could have an elevated transaminase level. Elevated
CPK level was reported in one-third of our cases. Sometimes the CPK level was very high, but in
all of the cases that we have checked, the CK-mb and troponin levels were not elevated, indicating that the CPK was
not coming from the myocardial muscle. We also found elevated LDH level in over
70% of our cases. (We eventually found the LDH level to be a prognostic factor.)
Hyponatremia and hypokalemia
was occasionally found in our patients. This
is a typical example, showing the progression of a patient’s chest x-ray from
day one to day two to day four.
Many
patients started off with a very clear chest x-ray, and then we would see a
diffused patch, usually peripheral and basal situated. In the early phase, it was
mostly unilateral and then at around the end of the first week, a more diffuse
infiltration and consolidation pattern involving both lungs and progression of
the disease was extremely alarming. In
cases where we had difficulty finding an abnormality on chest x-ray, we performed
a CT scan, in which we found typical consolidation patterns at the base of the
lung and in the more peripheral part of the lung which mimics the condition known
as “bronchiolitis obliterans
organizing pneumonia”. We found the CT
scan extremely useful when the chest x-ray could not detect anything.
Microbiology
investigations included sputum and nasopharyngeal aspirate for culture and PCR. In general, we had very little positive
yields from the cultures, which included three cases of Hemophilus
influenza, one Strep pneumonia
and one case of Klebsiella pneumonia. On NTA, we found one influenza A, one influenza B and two cases of RSV; however, when we
performed the electron microscopy, we found viral particles resembling both coronavirus and paramyxovirus.
This is the
protocol of our treatment from the very first day:
We treated
patients with fever, chills and rigors who were suspected to have SARS with
conventional antibiotics. We started with a betalactamase,
as well as a quinolone. Two days later, if the patient still didn't
respond, we gave them a ribavirin and steroids in
combination. Because of the large number
of patients we saw at the same time and because of the shortage of the intravenous
ribavirin at the hospital at that juncture, we chose
to give IV medication to those with more severe illness and desaturation
of oxygen. Oral ribavirin
and oral prednisone were given to the more stable patients in dosages as seen
on this slide. If the patient did not
respond, meaning that the fever persisted and the chest x-ray continued to progress,
we gave the patients intravenous pulse therapy of methylprednisolone
at 500 milligrams per day for two consecutive days. If fever still persisted and there were no
signs of improvement after two pulses of steroids, then we gave the patients
the third or the fourth pulse of the steroid.
Most patients responded to this treatment: fevers subsided, chest x-rays
improved and oxygenation also improved. For
those who still had not responded, we resorted to the use of convalescent serum
that we collected from patients who had recovered from the disease. In three patients, we also tried plasma
exchange as our last resort.
During this
time, some of the patients deteriorated and the lost oxygen saturation. These
patients were sent to the intensive care unit for further observation and even
required mechanical ventilation.
Following
is the outcome of our first 138 cases:
We admitted
32 patients into the intensive care unit -- 23% of the total number of cases.
Nineteen patients required ventilation. The patients who succumbed included two
with Myelodysplastic Syndrome(MDS),
two patients with liver failure, and one patient with heart failure. All five cases were originally patients from
the medical ward, all belonged to the older age group, and all suffered from
pre-existing comorbid illnesses. None of the health care workers or medical
students have died from the disease to date.
When we
look at the chest x-rays resolution by reading the digitalized x-ray, we see
that 82% of our patients now have more than 25% of resolution of the chest
shadow. 70% of patients have more than half of the x-ray shadow resolved in the
median duration of seven days.
The
post-mortem findings of two cases showed that there was early phase alveolar
damage, pulmonary edema, and hyaline membrane.
It also shows features suggestive of Adult Respiratory Distress Syndrome(ARDS). Lymphocytic
inflammatory infiltrates, vacuolated and multinucleated pneumocytes
were also seen and occasionally we also found viral inclusion bodies. Following are the factors based on univariate analysis that predict which patients require ICU
admission or which patients eventually succumbe:
older age, male sex, high neutrophil count, low
sodium level, high urea count, high CPK level and high LDH level.
On multivariate
analysis, we found only three factors that independently predict poor outcome. Advanced age, beginning at 40 years of age, differentiates
the high risk group from the low risk group.
An LDH level higher than 350 units per liter also predicts which will be
the poor outcome patients. The neutrophil count also
tends to indicate those with poor prognosis.
Those with the higher neutrophil counts have
more likelihood of ICU admission or death; however, we cannot find a clear cutoff
value for neutrophil count in this analysis.
These are
the dosages of the ribavirin that we use:
For
intravenous use, we give 5-8mg/kg three times daily, and for oral dose we use
1.2grams, because we understand that the oral bioavailability of ribavirin is 45%. We
considered carefully whether or not we should use nebulized
ribavirin, but since we learned from the experience
that using a nebulizer actually spread the infection,
we have decided not to use the aerosol ribavirin in
our treatment.
I want to
show you here a temperature chart of the patient who responded to pulse steroid. You can see that the red line represents the
temperature and the blue line represents the pulse. After two days of the oral ribavirin and the oral steroid, the patient still did not respond
and the chest x-ray started to deteriorate so, we gave him two pulses of
steroids. With this treatment, the temperature
gradually settled, only to come up again.
At that time, a third pulse of
steroid was given, and then the patient started to improve from there onward.
This is a
chest x-ray of one of our patients who started with only a patch in the right
lung. Three days later, he had very diffuse bilateral airspace consolidation,
at which point he was admitted to the ICU and given 100% oxygen. This patient was treated with IV ribavirin and hydrocortisone for almost 10 days without
much improvement, although his fever subsided.
His lung continued to deteriorate, however, and his oxygen had always
been marginal. Finally, we decided to
give him pulse steroid. In the lower part of the slide, you can see the
radiograph after two days of pulse steroid. Now the patient is recovering
outside the ICU.
Next is
another patient who received pulse steroid. You
can see on the left that he has more consolidation and diffused white
patchy consolidation as compared to the right. After he received pulse steroid,
there was more airspace, and his condition improved. We do have some side
effects using larger doses of methylprednisolone. This
included superimposed infection in 18 cases. We treated them with anti-MRSA,
anti-pseudomonas and antifungal therapy. Patients may also develop hypokalemia and hyperglycemia, but those are also easily correctable.
We used convalescent
serum in cases when, after three pulses of steroid, the patient still did not
respond. This is the protocol of our convalescent
serum preparation: We asked for donors who had recovered from the illness, had been afebrile for at least three days, and whose chest x-ray
showed definite resolution. The convalescent serum was given to patients who had
persistent fever and patients with recurrent fever who initially responded to
steroids but continued with leukocytosis either as a
reactivation of the disease or as superimposed infection. In this type of patient, convalescent serum was
considered to be safer than giving further pulses of steroid.
This is an
example of a patient who responded to convalescent serum:
Again, in
the red line shows the temperature and the blue line it shows the pulse of the
patient. After the first three pulses(mp indicates methylprednisolone),
the patient still had a high fever. At that time, on the 22nd of March, we gave
him convalescent serum, indicated here by cs. As you can see, the fever came down very
efficiently and the patient recovered from the illness. This is a typical
example of a positive response from among the 12 cases that we gave convalescent
serum. These patients were also given steroid and antibiotic therapy during
that time, so we are not sure whether the convalescent serum or antibiotic
therapy was the major reason for recovery.
This is a patient who received convalescent serum on day one, day two
and day three. The disease progressed
despite the use of ribavirin and steroid pulses, but
after convalescent serum on day seven, you see remarkable recovery of the chest
radiograph.
The lesson
that we have learned from the last three weeks is that high dose steroid should
be given early to stop the progression of the disease and to prevent
deterioration of lung function and ICU admission.
We have not
used the nebulizer or the noninvasive positive pressure
ventilation because we believe it would further spread the disease and endanger
health care workers looking after these patients. And in patients who had been
slowly recovering, we found that sometimes the lung volume shrank, with atelectasis setting in. Chest physiotherapy would be useful
in those cases.
This is the
result of our first 138 cases and, of course, we continue to have more patients.
We are adopting a more aggressive approach to therapy and we are finding that
the treatment result is better, though unfortunately in this crisis we cannot
have controlled data to prove that the therapy is valuable. However, I do believe that both ribavirin and steroids will be required going forward.
MODERATOR:
Thank you,
Dr. Sung. Our next speaker is here in
the studio with us. Please welcome Ms. Linda
Chiarello from the Centers for Disease Control and Prevention,
Division
of
Healthcare Quality Promotion, who recently returned from the field
investigation team in
healthcare facilities. Ms. Chiarello, welcome.
LINDA
CHIARELLO, RN, MS:
Thank you. I am pleased to participate in this educational
program and I say “hello” to colleagues around the world who are listening in today.
During my
recent visit to
In the time
available I plan to highlight the basic principles of infection control for preventing
SARS transmission in the health care setting.
Described
here are three premises that provide a basis for the development of the SARS prevention
program. We begin with the assumption that all SARS patients, regardless of
disease severity are highly infectious until proven otherwise. We also assume that hospitals will have to
implement measures that will protect vulnerable patients, staff and visitors as
well as prevent spread to the community.
Until the epidemiology of SARS is better understood, infection control measures
must target all possible modes of transmission including airborne, droplet, contact and through contaminated material or fomites in the environment.
Strategies
used to control the spread of other communicable infections in hospitals are familiar
to this audience, but they bear repeating in the context of the SARS prevention
strategy. Administrative measures are especially
important including good communication, education, clear policies and
procedures and enforcement of adherence.
Because there is a concern for possible airborne dissemination of this
virus, engineering measures to control and maximize air exchange both certainly
apply. The recommended personal protective
attire for SARS is intended to prevent exposures to a SARS agent that might be
spread through the air, respiratory droplets and direct and indirect contact
with respiratory secretions. These
include the role of masks, eye protection, gowns and gloves.
In
addition, protecting the environment of care, through surface cleaning and
disinfection and using care in the handling of waste and laundry are components
of a broad infection control strategy.
It is
helpful, perhaps to think of SARS prevention in the context of objectives that
need to be achieved. The first one is
early detection of possible SARS cases through traditional surveillance and screening
methods. The second is containment of infection
through source control measures such as having the patient mask or cover his or
her nose when coughing or sneezing, through patient placement, and the control
of ventilation. Third, is protection of personnel and
the environment of care through the infection control strategy I just mentioned. Fourth is hand hygiene. Hand hygiene is the cornerstone
of disease prevention. It protects
health care personnel and it protects the environment of care. While hand hygiene is not a specific
objective, perhaps, it is important for infection control and therefore merits
its own distinction.
Administrative
measures are critical for ensuring effective implementation of infection control
for SARS. Infrastructures currently in place
in many health care facilities to address concerns about bioterrorism are certainly
served in this setting as well. Systems
for communication, supply acquisition and distribution and traffic control are
some of the administrative measures that need to be addressed as part of the SARS
infection control strategy. Responsibility
should be assigned for placing SARS patients at the time of admission, implementing
and enforcing infection control measures and monitoring for transmission through
some of the surveillance strategies I will mention later
in
the presentation. Administrative
controls are also needed for limiting contact for SARS patients. At the discretion of the facility this might
require setting limits on visitation and designating a cohort of care providers
for the care of SARS patients only.
As I
mentioned a key objective is early detection of infection and it is critical to
containing and preventing the spread within the health care facility. A goal of this teleconference is to inform
and educate clinicians on signs and symptoms of SARS and to create, therefore a
heightened index of suspicion for SARS in patients who may be seen in primary
and emergency care areas.
It is also
important to have systems in place to intervene at the point of the initial
health care encounters. These may include use of signs to alert patients such
as the one seen here. Visual alerts are
used to instruct patients. Providing masks at the entry to reception areas,
encourages
containment of respiratory droplets. Patients
who may have SARS should be segregated from other parents as soon as possible
and preferable placed in a private room.
Communication
is another important aspect of early detection and infection control personnel
should be notified when a possible patient with SARS is admitted to or presents
to a facility. This will ensure the
appropriate implementation of measures for infection control following admission
as well as the notification of public health authorities.
Lastly, the
use of personal protective attire that I will
describe shortly should begin at the first point of patient
contact and continue until the point of discharge or determination of noninfectiousness.
The second
objective is containment of infection. Containment
of infection begins with source control and segregation or separation of patients
with SARS like symptoms. However, one of
the key infection control measures here is to contain and safely remove the infectious
air around the patient.
The
preferred option is to place the SARS patient in a private room that is under
negative pressure relative to the surrounding air with air filtered to the outside. The door should remain closed and access
should be limited to those persons who must enter for purposes of providing
patient care. However, in many areas of
the world negative pressure environments are not available and appropriate
accommodations must be made.
Natural
ventilation can be maximized by opening windows and air can be directed outside
through the use of exhaust fans. Surgical
masks may be worn by the patient as tolerated and safe for patient care. Containment of infection also involves
decisions about patient placement.
A private
room for SARS patients is preferred when available. SARS patients should not be placed in the
rooms with other patients who do not have a SARS-related diagnosis. In some cases because of the number of SARS
patients being admitted it has become necessary to cohort SARS patients on designated
wards. When this is done, the same ventilation
strategies should be considered. And it
is worth noting here that when SARS wards are established, patients undergoing
initial evaluation for possible SARS should not be placed in the SARS
ward. Instead, to avoid unnecessary exposure
in the event such patients are not infected, they should be placed in a private
room until SARS has been ruled out.
An
administrative measure to help contain infection and prevent unnecessary
exposure is to limit the number of patient contacts. This can be done through various options for
visitor restriction as well as by using dedicated staff to care for SARS
patients. This is probably more
important situation where SARS is spreading in the community or if there has
been transmission within the hospital.
Options for
limiting visitors are listed here, however, these decisions
are best left to individual health care facilities and may depend on
transmission patterns that have been observed. The third objective is to protect
patients and the environment of care. As
mentioned earlier, until the epidemiology of SARS is clear, all modes of
transmission must be considered when determining appropriate measures for protecting
personnel. Protection of the respiratory
tract is necessary to prevent airborne and droplet transmission. An approved respirator such as an N95 is recommended
for preventing exposure from airborne droplet nuclei. In the
Large
infectious droplets may be generated when a patient coughs,
sneezes or speaks. Dispersion of these
droplets is generally limited to the area close to the patient. A standard surgical mask is recommended for
preventing exposure to respiratory droplets.
However, because
both respiratory and droplet modes of transmission are being considered, an
approved respirator is the preferred mask for personal protection. However, if a mask is not available, a
surgical mask should be worn.
Masks
should be applied when entering the room or a ward housing SARS patients and ensuring
a snug fit over both the nose and mouth is necessary to optimize the protective
benefits of this device. The mucus
membranes of the eyes also must be protected from exposure. Goggles or face shields offer the necessary
protection from respiratory spray that must be generated through patient care.
Protective
attire is necessary to protect exposed skin as well as well as clothing of health
care personnel.
Gowns,
disposable or washable and disposable gloves should be worn for contact with
patients and their environment.
It would be
necessary to don this attire prior to entry and remove it before leaving the
room.
In wards
dedicated for the care of SARS patients, health care personnel generally wear
the same gown over the course of a shift and change it only if it becomes
soiled.
However,
gloves should be routinely changed and hand hygiene performed between
patients. Head or shoe covers also may
be used if dictated by cultural norms or regulations. Since there is evidence that coronavirus can survive on environmental surfaces, protection
of the environment of care is critical to interrupting transmission.
Standard
measures for handling contaminated material should be followed,
some measures such as those for infectious waste may be dictated by local regulations.
Soiled linens and laundry should be handled carefully including the avoidance
of sorting and other measures that could generate airborne contaminants. Designated bags should be used for containment
of contaminated linens and laundry and standard laundering procedures already
in place should be followed. Bleach is
not necessary, but may be added to the wash cycle if desired. Eating utensils used by patients with SARS
should be washed in a dishwasher or by hand using dish soap and warm
water. Disposable dishes and utensils are
not considered necessary. There is no
need to change the type of disinfectant used based on concerns about
environmental contamination with the SARS agents. Either a hospital grade disinfectant or a 1 to
100 dilution of household bleach in water may be used. It should be assumed, however, that the
immediate environment around the patient with SARS is heavily contaminated.
Daily
cleaning will reduce this bioburden and should focus on
areas close to the patient including bed rails, overbed
table, nightstand, sinks, lavatory facilities and other equipment in the room. Cleaning will also be facilitated if there's
limited clutter in the patient's environment.
Following
patient discharge, the room and all reusable patient care equipment should be thoroughly
cleaned and disinfected in accordance with current cleaning and reprocessing
procedures.
The fourth
key objective is hand hygiene. As I mentioned earlier, hand hygiene is the
cornerstone of prevention and should be performed following all contact with suspect
and probable SARS patients and their environment. Hand hygiene methods include traditional hand
washing with soap and water followed by drying, preferably with a disposable
towel and the use of alcohol-based hand rubs.
Hand washing should be performed any time the hands are visibly soiled.
While
alcohol-based hand rubs may be used as an alternative when the hands are not physically
soiled and when hand washing facilities are not available in the patient room.
There are a
few other considerations that I would like to mention as part of this presentation.
As Dr. Sung
mentioned earlier, the use of nebulizers has been thought
to be associated with possible transmission to medical personnel in his
facilities. Therefore, when possible, nebulizers and other cough-inducing procedures should be
avoided. If necessary for patient care, such procedures should be performed in
a separate area, in a negative pressure environment with personnel wearing
appropriate protective garb.
Patient
movement should also be limited to the extent possible. If transport is
required for patient care,
the patient should wear a surgical mask and clean attire
or
cover gown.
Personnel
who have been exposed and might be incubating SARS need to be monitored for evidence
of early disease or infection. Surveillance
of SARS contacts is also necessary for assessing the effectiveness of infection
control measures. A list of health care personnel contact should be maintained
and personnel should be monitored for signs and symptoms of SARS, if not daily,
at least every two or three days. A
listing of other patient contacts should also be created for surveillance
purposes.
The strategies
and objectives of SARS prevention are shared globally,
however, several factors will influence their interpretation and implementation. Country differences and differences within
countries are likely and should be appreciated.
We need to understand that cultural patterns of health care delivery,
including the use of families as primary care providers may be an important influence
on the type of measures implemented for infection control. The hospital infrastructure, when there is
the capacity to engineer the direction of air flow is an important consideration. Knowledge and experience of health care
personnel caring for patients with a communicable disease and their familiarity
with principles of transmission-based isolation techniques will vary.
The
availability of resources, both in developed and developing countries is a very
serious concern as these resources dwindle with the rise in the number SARS
cases.
Decisions
are necessary about reuse of many of the protective devices that are used for
health care personnel.
Finally,
variation in infection control will probably be observed as a result of the level
of SARS in the community and whether transmission has been observed within the
health care environment. I would
encourage you to go to the WHO and CDC web sites for the most current
information and recommendations for infection control prevention for SARS.
In the
final analysis, prevention is primary. Early detection and implementation of
the infection control measures I just described will have the greatest impact
in protecting health care personnel and health care facilities from SARS. Thank you.
MODERATOR:
Thank you,
Ms. Chiarello.
We appreciate your expertise.
Our final
speaker, also here in the
Dr. James Hughes, Director of the
JAMES M.
HUGHES, MD:
Thank you
very much. CDC is one of 12 institutions
in
10 countries working collaboratively under WHO leadership to
investigate SARS. On March 14, CDC Director Dr. Julie Gerberding activated the
This was
the day as Dr. Heymann mentioned that the cases in
In
addition, nearly 300 CDC staff are currently working
at headquarters and throughout the
colleagues at the state and local level in confronting this
problem.
This slide shows the epidemic curve by date of onset of illness for suspected SARS
cases in the
94 of those
are in people with travel to affected areas, four are in individuals shown in green
who have had a direct contact with people who are ill, who have traveled to
affected areas and, two, shown in red, are health care workers who have had
contact with other SARS patients.
On March
24th, CDC released information that it had recently developed suggesting that a
previously unrecognized new coronavirus may be the
cause of SARS.
To date,
laboratories in at least seven other countries also have evidence of a corona,
virus likely playing a role in the cause of this syndrome.
Let me
provide you with just a bit of background on coronaviruses. These are single stranded RNA
viruses, they are non-segmented and they are enveloped and genome is 31,000
nucleotides. There are two serogroups that are recognized
to cause infection in humans 229E and OC43 represent the two coronaviruses that are recognized to be responsible for
about one-third of colds. Reinfection with
these viruses are common. The
viruses contain an envelope.
They have
an S-Spike protein and a Matrix protein and some of them, in addition, have a Hemagglutinin esterase protein as well.
These
viruses do survive for short periods of time in the environment. There is a relatively limited data available,
but what we are aware of indicates that 229E virus can survive as long as six days
in suspension and up to three hours after drying on environmental surfaces. OC43 has been evaluated and shown to survive
for less than an hour on surfaces after dry. This slide summarizes the laboratory
data from CDC through April 3rd suggesting that the previously unrecognized coronavirus plays an etiologic role in this syndrome.
In specimens
from four patients, we've been able to culture this virus in VERO E6
cells. Electron microscopy
performed by CDC have found evidence of a coronavirus
in cell culture or in one case, bronchioalveolar lavage fluids from two patients. In addition, recently developed
PCR assays evaluating tissues and swabs that found evidence of coronaviral nucleic acid in 11 patients recently developed
antibody tests using an IFA or an EIA methodology have demonstrated evidence of
infections in five patients and the histopathologic studies
have revealed evidence of the diffuse alveolar damage or DAD which is the
pathologic equivalent in the adult respiratory distress syndrome in four patients.
Let me now
show you some images of this coronavirus first in an
infected VERO E6 cell evaluated by thin section EM.
You may be
able to see the small viral particles along the surface of the damaged cell. In
the next graphic you will see a thin section electron micrograph showing a more
detailed view of this coronavirus. And then on a higher power you can see using
negative staining, a coronavirus particle. These
viruses are named for the fact they have the surface projections resembling a
crown around the core of the virus particle and you can see that the diameter
is a bit less than 100 nanometers.
This slide
shows evidence of virus in fluid obtained from bronchoalveolar
lavage from a SARS patient. You can see there the intracellular virus on
the right. This slide shows the lung
using routine histopathological techniques where you
can see evidence of diffuse alveolar damage and in the center syncytial multinucleated giant cell. Here is a close-up view of the syncytial multinucleated giant cell seen in the lung of one
of these SARS patients. There is much
additional laboratory work in progress here at CDC and in many laboratories around
the world.
Some of our
priorities include, immunohistochemical staining in
an effort to demonstrate virus in affected tissue, similarly we are working on in
situ hybridization techniques to achieve the same end and we have viral sequencing
under way. Sequencing to date of one of
the genes of the coronavirus suggests that it indeed
is a member of a fourth antigenic group of coronaviruses
and it has suggested evidence that this is a previously-unrecognized coronavirus. That
completes my laboratory update. Thank
you very much.
MODERATOR:
Dr. Hughes,
before you go, certainly you have given us important information. If you can summarize, the key areas of
concern at this point in the investigation and if you can tell us what CDC and WHO
is doing to stop the spread of
SARS?
JAMES M.
HUGHES, MD:
Thank you, Kysa. Let me call the audience's attention to a very timely
and very important report issued two weeks ago by the
This report
is called Microbial Threats to Health, Emergence, Detection and Response. It represents
a follow-up report to a report that the
Let me
suggest that this disease, SARS, is emerging for a number of reasons. If you look at this recent
They
include changes in human demographics and behavior, issues related to human susceptibility
to infection, the impact of economic development and changes in land use patterns,
changing ecosystems around the world, the dramatic impact of international
travel and commerce, the volume and speed with which we and animals and
commodities can move around the world and we've seen SARS spread very dramatically
in a very short period of time. Microbial
adaptation and change which is what makes infectious diseases unique and
finally and very importantly breakdown of public health measures as a result of
which many countries have inadequate capacity to respond on their own to these
emerging microbial threats. In looking a
bit more closely at the IOM report you would find 21 recommendations. At least seven of these, again, I think apply
directly to what needs to be done to confront SARS.
We must
enhance global response capacity further under the leadership of the World Health
Organization and Dr. Heymann's group. We must
continue to work to improve global infectious disease surveillance. We must
rebuild domestic public health capacity at the local, national and global
level. We must develop diagnostics. Obviously, one of the critical needs right
now is rapid, sensitive, specific diagnostic tests for SARS.
We must
educate and train the multidisciplinary workforce that is required to confront
these very complex challenges.
We must
focus on vaccine development and production. Clearly, there is a need now for efforts which
are already under way to rapidly develop a safe and effective vaccine for this
disease. Then we need new antimicrobial
and in this case, antiviral agents to use along with other therapies to
confront this infection.
Now there
are many things that we need to know and we are right in the middle of this and
the future course of this outbreak at this point is impossible to predict.
We have
heard about the aggressive infection control procedures that need to be put in
place when there is an index of suspicion of SARS. This currently constitutes our best available
tool to limit spread of this agent.
We would
like to know the original source of the virus. We need to know more about how it
is transmitted in the community. You've
heard about large droplets being most likely to be the most important mode of transmission,
but we need to keep an open mind in terms of fomites the
possibility of airborne spread.
We need
better information on the risk of household transmission. We need better information on the risk of
transmission on airplanes and ships. We
need more information on environmental persistence as it relates to the decontamination
of environments. We need to know the
period of infectiousness of individuals with SARS. We would like to know the explanation
for the age distribution as Dr. Hall provided us. There seem to be in some cases hypertransmitters, people who are infected, ill but
unusually able to transmit this virus in health care or home settings. We need to know the explanations for that. As more laboratory work is conducted, we need
to sort out the possibility of coinfection. We know
that other laboratories have found evidence of paramyxovirus
in some patients. We need to identify and employ and implement optimal
diagnostic tests and we need to know the most effective therapy and the most
effective approaches to vaccine development.
So much has
been accomplished in the past few weeks since this outbreak was called to the attention
of experts around the world, but we are early in this, much more work
definitely needs to be done.
I'd like to
refer back to the web sites of both the World
Health Organization
and the Centers for Disease Control and
Prevention
because these will continue to provide you with the most current, updated information
on the course of this emerging global microbial threat.
Now,
finally, in closing, I would like to reflect just briefly on some of the
lessons that we have already learned from SARS and we must bear these in mind. This experience emphasizes the importance of
strong national and international collaborations and partnerships, the need for
planning and practice for outbreak response and we are reminded very vividly of
the need to continue to expect the unexpected from the microbial world.
In
finishing, again, I would like to recognize and congratulate Dr. Heymann and his colleagues at WHO
for their leadership in this global investigation. I would like to acknowledge
the efforts of investigators and clinicians and laboratorians
around the world who are working day and night to control this problem. Finally,
I would like to sympathize with those individuals who have been impacted
directly or indirectly by this disease. Thank
you.
MODERATOR:
Dr. Hughes,
thank you. It certainly appears we are
on the right road to finding out all about the SARS epidemic.
We want to
go back to
JULIE
HALL, MD
Thank you
again. In summary, Severe Acute Respiratory Syndrome is a very important
disease. It is important based in terms
of what we know about it and what we have yet to learn about this disease. What
we know is that SARS has the potential to spread rapidly, particularly in
hospital settings. What is also known is that with early detection and the high
index of suspicions, if patients are detected early and the appropriate
hospital control measures used and the patients put in isolation, then the transmission
of this disease can be dramatically reduced. What also
is known about this is that the unprecedented global collaboration that has
taken place has reaped immense rewards. Both
in terms of the awareness of this condition, in terms of the awareness of the
need for isolation of suspect and probable cases and in terms of the modes by
which transmission can be reduced. However, much further work is required. Work
is required as Dr. Hughes said, to understand this
agent in more detail, to get a better understanding as to the mode of transmission
of this agent, to develop diagnostic tests, to develop treatments and to develop
a vaccine.
All of this
is only possible through continued global collaboration and I would like to take
this opportunity to thank all the partners, all of the organizations and
institutions within the global outbreak alert and response network who have contributed
to the effort that has been ongoing with SARS so far.
I'd also
like to thank CDC for this opportunity to be involved in this broadcast. So in summary, thank you all
very much for this and I'm glad that we have had an opportunity to raise
awareness of SARS and awareness of the need for us to collaborate together to
reduce the transmission of this disease.
So thank you to CDC.
MODERATOR:
And we
appreciate you, Dr. Hall. One last reminder for our viewers, don't forget to
visit the CDC and the World Health
Organization websites for the latest information on SARS.
Again,
those addresses are-- The World Health Organization
website's address is-- www.WHO.int. The web address for the CDC is www.CDC.gov.
It has been my pleasure being your moderator for this broadcast. I'm Kysa Daniels
and for everyone at the World Health Organization in
END