Operator:
Good day everyone and welcome to today's RHC
preparedness pandemic flu conference call. Today's conference is
being recorded.
At this time, I'd like to turn the conference
over to Deb Havens. Please go ahead.
Deb Havens:
Good afternoon, everybody. I'd like to welcome
all the callers and the participants to today's presentation on
RHC preparedness pandemic flu with our speakers Dr. Niranjan Bhat
with the influenza branch of the National Center of Infectious Diseases
at the Center of Disease Control and Prevention and Dr. Adam Cohen,
an Epidemic Intelligence Officer with the Division of Healthcare
Quality Promotion at the CDC.
Also joining us on the call today during the
question and discussion segment is Captain Nancy Egbert the Senior
Clinical Advisor of the Office of Rural Health Policy.
This program is scheduled for an hour. The first
45 minutes is going to consist of our speakers' presentations. The
remaining 15 minutes will be dedicated to questions and discussion.
The series of calls is sponsored by HRSA, Federal Office of Rural
Health Policy, in conjunction with the National Association of Rural
Health Clinics.
The purpose of the Rural Health Clinic's technical
assistance conference call series is to provide Rural Health Clinic
staff with valuable technical assistance and RHC-specific information.
Today's call is our eighth call in the series, which began in 2005.
There's no charge to participate in the Rural
Health Clinic's technical assistance conference call series. Individuals
can sign up to receive announcements regarding the call dates, topics,
and speakers' presentations at the following Web site: www.ruralhealth.hrsa.gov/RHC.
During our question and discussion segment of
the call, we request that all callers please provide their name
and their location before you ask your question. In the future,
you can also email your question to the following Web site, info@narhc.org
and put the teleconference question in the subject line.
All of your questions and answers will be posted
at the (ORHP) conference call series Web site and the NARHC Web
site, which is www.narhc.org.
You should have received an email already in advance
of today's call providing a link to both of our speakers' PowerPoint
presentations to follow along during the call. The call transcript
will also be available at the ORHP Web site at http://www.ruralhealth.hrsa.gov/rhc/.
And now I'd like to welcome our first speaker,
Dr. Niranjan Bhat. So take it away, Dr. Bhat.
Niranjan Bhat:
Thanks. My name's Niranjan Bhat. I'm with the
Influenza Branch at the CDC. And I'd like to talk this afternoon
about seasonal, avian, and pandemic influenza.
I hope most of you have been able to download
my slides, and I will be following along those. So I'll try to indicate
when I'll be moving to the next slide.
So starting with slide two, first I want to say
that influenza definitely has a public health impact. It is an annual
public health problem that occurs predictably. We know that we will
have an influenza season every year, and its health impact is substantial.
It infects 10 to 35 percent of children each
year and five to 20 percent of adults. And this has substantial
economic consequences, including lost work, lost school days, and
during the peak of the season, overwhelmed medical care systems
at times.
In addition, because of the possibility of influenza
pandemics, influenza represents a singular global infectious disease
threat as well.
Next slide. So what is influenza? Influenza is
often called the flu, which in general terms is an acute febrile
respiratory illness. But what the general public considers a flu
illness may actually be caused by any of a number of pathogens,
mainly respiratory viruses.
But influenza particularly is caused by infection
with an influenza virus. classically this is characterized by fever
plus cough or sore throat, often called an "influenza-like
illness" since it's usually not laboratory confirmed.
Next slide. There are other features of influenza
that most people are familiar with, including headaches, fatigue,
and body aches. One of the signal features of influenza, as opposed
to the common cold for instance, is its rapid onset. But also the
range of symptoms differs by age.
In children, vomiting and diarrhea can be present,
but this is usually absent in adults. And in infants, influenza
can present as fever alone, or as apnea.
Because of its non-specific nature, influenza
is often confused with other illnesses. other viral illnesses, colds,
as well as stomach flu, are some of the other illnesses that can
be confused with influenza.
Next slide. Among respiratory viruses, influenza
is considered to be highly contagious and transmission is primarily
person to person with an incubation of one to four days. Serologic
studies have shown that subclinical infection can occur.
Next slide. The infectious period for influenza
may begin one day before symptom onset in adults. And it may even
be longer or earlier in children. The peak viral shedding for influenza
is on the first day of symptoms and adults shed for four to six
days.
Infants and children may shed longer than this,
and immuno-compromised patients have been shown in anecdotal reports
to shed for months.
Influenza is unique among respiratory viruses
in the degree of morbidity and mortality that it causes. In the
United States, influenza is attributed to cause an average of more
than 200,000 influenza-related hospitalizations and about 36,000
influenza-related deaths annually.
The highest rates are in persons with chronic
high-risk conditions in all groups and in certain age groups, in
particular, children with highest rates in the young children less
than two years of age and adults age 65 or older. In fact, of those
36,000 influenza-related deaths, more than 90 percent are in the
elderly.
Influenza vaccination is recommended but based
on high risk categories. These are initially or primarily age groups,
that age 65 or older, children age six to 59 months, as well as
those age 50 to 64 years.
Of course, those with high-risk medical conditions
age six months or older are recommended for influenza vaccination
as well. In addition, household contacts of high-risk persons and
healthcare workers are recommended for influenza vaccination.
In terms of treatment, there are a number of
anti-viral influenza drugs. Regardless of the medication, treatment
for influenza is usually a five-day course but needs to be started
within 48 hours of illness onset for maximum benefit.
Influenza antiviral drugs are shown to reduce
symptoms by approximately one day. And other studies have indicated
that they also have an ability to decrease hospitalizations. In
addition, influenza antiviral drugs reduce viral shedding.
Antivirals are also used for another indication,
chemoprophylaxis. These antivirals are 70 to 90 percent effective
in preventing illness from influenza. While infection may still
occur, viral shedding, and therefore transmission, is reduced.
Examples of chemoprophylaxis are for control
of nosocomial outbreaks in hospitals or long-term care facilities
and for patients who cannot receive vaccine, for instance due to
hypersensitivity.
There are two classes of influenza antivirals.
The first class, known as adamantanes, are an older class of drugs
that include amantadine and rimantadine. These are effective against
only type A influenza viruses and are not currently recommended
because there's a high frequency of resistance among currently circulating
strains.
The other class of drugs are neuraminidase inhibitors
and include oseltamivir and zanamivir. This is a newer class of
drugs that are effective against both influenza A and B viruses.
The approved ages for these four drugs varies
by drug and indication, and there is no treatment or prophylaxis
approved for children aged less than one year.
In terms of influenza testing, viral culture
is gold standard. This requires growth in cell culture and takes
anywhere from four to 10 days for results. Serology is also another
method that has been around for a while but usually requires paired
samples so that background non-specific reactivity, which is common,
can be compared to a rise in convalescent titers.
Immunofluorescence is another method that is
relatively rapid but requires good technical skill. Reverse-transcriptase
polymerase chain reaction is a test that is becoming more popular
due to its rapid turnaround time as well as high sensitivity and
standard technology.
And finally rapid diagnostic testing, which many
clinics may be familiar with, is a very popular method because it
is relatively simple to perform, and your are able to get an answer
within 30 minutes. some brands can be used in the clinic itself.
However, there are problems with their sensitivity.
The ideal specimen for seasonal influenza is
a nasopharyngeal swab. But nasal swabs, nasopharyngeal aspirates
and nasal aspirates are also useful and preferred over pharyngeal
swabs.
Because viral shedding is highest at the beginning
of the illness, it's best if these specimen is taken close to illness
onset, at least within four days. And it's interesting to note that
optimal specimen sites can differ for non-human influenza viruses
such as avian influenza, also known as bird flu.
So now to a little bit of virology. Influenza
illness is caused by infection with an influenza virus, and this
virus primarily infects the upper respiratory tract. The virus is
a negative single-stranded RNA virus, and it contains eight gene
segments that code for 10 proteins. This segmented nature of the
virus is important in understanding its biology.
Influenza viruses are classified into types A,
B, and C, with A and B causing most human illnesses of significance.
Influenza A viruses are further characterized
by subtype, and these subtypes are determined by two surface glycoproteins:
the hemagglutinin protein and the neuraminidase protein. Hemagglutinin
is the site of attachment to host cell surface receptors and antibodies
to hemagglutinin are protective. Therefore, that's the target for
vaccination.
The neuraminidase is a protein that is an enzyme
that takes part in the release of virions from the cell.
Influenza A subtypes can come in 144 varieties.
There are 16 H types and 9 N types. And so influenza A viruses are
designated by the H and a number and an N and a number, such as
H1N1 or H3N2.
The subtypes are specific to certain species
of animal so that for instance humans can only be infected by a
certain subset of H types. only H1, H2, and H3 are in common circulation
in the human population while sporadic infections have been detected
for H5, 7, and 9.
As the figure shows, there are subtypes that
can infect swine, marine mammals, horses. All subtypes can infect
migratory water fowl, such as ducks, geese, and seagulls. Therefore,
avian influenza viruses are thought to have its reservoir in the
bird population. And this population serves as a source of influenza
viruses for other species.
There are two ways that influenza viruses can
change to evade the immunity of the population. The first type is
called antigenic drift, characterized by minor antigenic changes
to the hemagglutinin protein.
This is a continuous process because influenza
is an RNA virus, there is a poor quality of replication, so there's
continuous mutation that goes on. This antigenic drift allows for
escape from population immunity and can lead to a new replacement
strain over the year for a particular subtype.
Antigenic drift leads to seasonal epidemics,
and therefore vaccine strains must be updated each year. The US
Influenza vaccine typically contains two type A strains, H1N1 and
H3N2, and one type B strain, which covers all subtypes that currently
circulate in the human population
The other method for change in influenza viruses
is antigenic shift. This is where there's an emergence of a novel
human influenza A subtype, usually from another animal population
into the human population.
This can occur in two different ways. One is
through direct bird-to-human transmission, through the mutational
adaptation to the human host, or through genetic reassortment between
human and animal influenza viruses.
Here is where that segmented nature of the influenza
genome becomes important, because if a host, either a human host
or an intermediate animal host, is infected with two different subtypes
of influenza virus, those two different strains could swap genetic
segments and gain the ability of transmission for one and the virulence
of another.
This diagram, which is slide 18, demonstrates
the first type of direct infection from birds to humans. And then
slide 19 shows reassortment through an intermediate host.
Antigenic shift is important because it can lead
to influenza pandemics. The requirements for influenza pandemic
is the emergence of a novel human influenza A subtype into the human
population, in other words, antigenic shift, and efficient human-to-human
transmission, and also that the virus causes significant human disease.
A pandemic can result in increased overall morbidity
and morality. But in particular, there's usually a higher proportion
of deaths in younger adults.
Within the past century there have been three
influenza pandemics: One in 1918 which led to 20 to 50 million deaths
worldwide and over half a million deaths in the U.S. alone; the
1957 pandemic, which led to 70,000 U.S. deaths; and the 1968 pandemic,
which led to 34,000 deaths.
It is thought that at least three pandemics have
occurred per century on average based on historical records. But
since the influenza virus was not identified until the 1930s, it's
unknown whether influenza was the cause for each.
You may notice that the pandemics of '57 and
1968 had substantially fewer deaths. But the morbidity was still
quite high.
You may also notice that mortality in recent
years is, on average, 36,000 U.S. deaths per year, which is greater
than the 34,000 you'll see in the 1968 pandemic. The thought is
that during that time the population in the United States was smaller,
that the proportion of the U.S. population that were elderly or
had underlying medical conditions were smaller, as well as the fact
that while the H3 antigen did change, the N2 remained the same from
the previous years.
And all of these are thought to have factored
into the difference between the 34,000 and the 36,000 currently.
You can also notice that these pandemics signaled
the entry of a new subtype. In 1918, it was H1N1. In 1957, it was
H2N2, and in 1968, it was H3N2. And currently the H3N2 strain and
H1N1 strains are still in circulation.
Well, what would be the impact of a new influenza
pandemic? Back in 1999, we projected the impact of a future pandemic
based on the '57 and '68 pandemics. And the number of deaths are
projected to be between 89,000 and 207,000; hospitalizations between
300,000 and 700,000; outpatient visits as well as other additional
illnesses range in the millions; economic impact over 150 billion;
and the population affected could be around 15 to 35 percent.
So slide 23, pandemic influenza, it's important
to compare this with what has been in the media lately, which is
avian influenza A H5N1, also known as bird flu. It's important to
know that avian influenza H5N1 is not a pandemic virus at the moment.
It is a new subtype from an animal source, and it does cause significant
disease in those infected.
But it hasn't gotten the third requirement for
a pandemic virus, which is easy human-to-human transmission. The
clinical features of a pandemic influenza virus would be expected
to be similar to a seasonal influenza but perhaps more severe in
its presentation.
These would include fever and respiratory symptoms,
and this is based on experience with the previous pandemics.
Because of the non-specific nature of, or non-specific
symptoms of influenza, diagnosis, definitive diagnosis would still
require laboratory confirmation. But during the midst of a pandemic,
laboratories will likely be overwhelmed, and one would expect that
clinical features alone will be sufficient for management of a pandemic
influenza patient.
A pandemic influenza virus would be expected
to be susceptible to neuraminidase inhibitors such as oseltamivir
(Tamiflu) or zanamivir (Relenza). And it is possible that it may
be still sensitive to the adamantanes.
Prevention of pandemic influenza would rely on
the development of a pandemic vaccine as well as through non-pharmaceutical
interventions, including isolation, quarantine, social distancing,
and infection control. Interventions can range widely in their degree
of intrusiveness, and the current idea is to keep them as minimal
as possible while remaining effective. For instance, quarantine
can be instituted on a completely voluntary basis, asking people
to stay at home as much as they can for example, which is more likely
in a country like the US, or enforced quarantine, which would involve
many complex legal and logistical issues, would only be used in
extreme situations.
And control during an outbreak will again rely
on treatment, prophylaxis, and non-pharmaceutical interventions.
Department of Health and Human Services has developed
a pandemic influenza plan that supports the National Strategy for
Pandemic Influenza. And this pandemic influenza plan outlines planning
assumptions and the doctrine for health sector pandemic preparedness
and response.
There's also guidance for state and local partners
with 11 supplements that give guidance on surveillance, testing,
infection control, clinical management, as well as community interventions.
All of these documents can be accessed at the
Web site listed on slide 24, pandemicflu.gov.
The objectives of the pandemic plan are to first
prevent or at least delay introduction of a pandemic virus into
the United States. And this may involve travel advisories, exit
or entry screening, and for the first cases, it may involve isolation
or short-term quarantine of arriving passengers.
Now in this age of rapid travel and mobility,
it may be very difficult to prevent the introduction of a pandemic
virus into the United States. Therefore, our next objective is to
at least slow the spread, decrease illness and death, and buy time
once the pandemic arrives.
This can be achieved through many ways, including
antiviral treatment and isolation for people with illness, quarantine
for those exposed, if feasible, social distancing, vaccine when
available, and many of these decisions will have to be made locally.
On the graph that's shown on slide 26, it shows
the difference between an unprepared and a prepared response to
a pandemic. And the goal is to decrease the height of that peak
because even if we can't completely prevent the pandemic virus from
entering a community, we can at least try to slow its spread and
decrease the peak so that services won't be stretched beyond surge
capacity
Another objective of the pandemic plan is to
include a clear communications strategy for the public. We want
to be able to prepare people with information ahead of time. For
instance, I've been asked before whether it's still safe for children
to visit petting zoos or farms, to interact with chickens at school.
at this time it's considered safe to do that, but it's important
for people to know that there may come a time when it may not be
safe. It's important for the public to understand ahead of time
what the realm of possible interventions could be, and when they
may be started, so that they are not taken by surprise or don't
overreact to a perceived threat.
We want to encourage the public to take steps
to prepare now, we want to provide updates when new information
emerges, to use trusted messengers, to coordinate to ensure consistent
messages across agencies, and to address rumors and inaccuracies.
We also hope to develop a pandemic vaccine. This
can best be done by expanding and stabilizing production of the
current influenza vaccine for seasonal influenza. We want to evaluate
dose-sparing technology so that we can spread the current vaccine
production capacity to cover more people.
We'd like to accelerate development of moderate
vaccine technology. Currently, influenza vaccines are produced by
using chicken eggs, which is a very slow process. We also want to
target new antigens that are conserved from one influenza strain
to the next so that we don't have to update the vaccine strains
every year, or design a specific vaccine just for a pandemic virus
strain.
In terms of antivirals, the U.S. government plans
to stockpile a certain amount of antivirals, including oseltamivir,
zanamivir, and the goal is to get enough quantity to treat 25 percent
of the United States population.
Now, how antivirals and vaccines are going to
be distributed is a matter of great complexity that involves issues
regarding ethics, social justice, effectiveness, and science, and
will take some time before concrete plans can be disseminated. But
the U.S. government is working in close collaboration with the states
as well as influenza experts, the vaccine manufacturers and the
antiviral manufacturers to work this issue out.
Again, the strategy with antivirals is for use
in initial containment, if that's feasible, and for treatment, especially
those who are at higher risk. there is going to be an issue with
prioritization of both antivirals and vaccine.
We'll have to balance the science with values
regarding what is the most fair method for prioritizing antivirals
and vaccine. this matter is being discussed at all levels and has
engaged the public in many venues.The two objectives for the pandemic
response are to preserve societal functioning and to protect those
most at risk. And deciding which takes precedence is really a matter
of quite a lot of debate.
Of course, the pandemic plan includes the evaluation
of new antiviral candidates.
In terms of funding for states, the pandemic
plan includes $350 million for state and local response capacity.
And at this point, $100 million has already been awarded to all
50 states, seven territories, and this amount has been allocated
according to a base figure plus a population formula.
In addition, $250 million will be awarded later
this year.
Pandemic planning involves a network of responsibilities
from the local to the state to the federal level, both domestic
U.S. plans as well as coordinating with international plans, international
agencies, and other countries.
It both involves the public sector as well as
the private sectors as businesses plan. And it's non-partisan. It
involves animal as well as the human health sectors and involves
protection of health, security, as well as the economics of this
country.
To help prepare, HHS has put together a series
of pandemic influenza checklists. These are basically lists of things
that different organizations need to think about and plan for in
order to become prepared for a pandemic.
There are different checklists that are available
on the pandemicflu.gov Web site, those for state and local organizations,
businesses, schools, faith-based and community organizations, and
the travel industry. And most relevant for this group, checklists
for physician offices and ambulatory care, home health and emergency
medical services.
In particular, the state and local public health
checklists include items on community leadership and networking;
surveillance; health system partnerships; infection control and
clinical care; vaccine distribution and use; antiviral drug distribution
and use; community disease control and prevention; communications
and workforce support; while for medical offices and clinics, they
include sections on starting a planning committee; developing a
plan, surveillance and detection among their patients, communications
with public health, other facilities, staff, and patients; education
and training; triage management and infection control of infected
patients; occupational health and surge capacity planning; and then
antivirals and vaccines.
Now, these checklists are probably not at the
level of detail that the public would like at this stage, but it
is an ongoing process. And as the HHS develops its operational plan,
further details will be available as time goes along.
There is advice for individuals, that advise
families to store and supply some water and food, to have non-prescription
drugs and other health supplies on hand, to talk about what will
be needed to care for family members in the home, and for individuals
to get involved in the community to volunteer with local groups
to prepare.
So future directions for pandemic planning include
more detailed guidance, including universal preparedness that can
be used for any type of health emergency; to develop exercises at
all levels -- local, state, as well as federal; to go through their
pandemic plans; integration of different sectors within health,
security, economic, and animal sectors; and, of course, all of these
pandemic plans will require frequent updates and adaptation as events
change.
The overall goal is preparedness but not panic,
to inform but not to inflame.
So I'd like to end with just a summing up of
seasonal, avian, and pandemic influenza viruses.
Seasonal influenza viruses are a public health
problem that occurs every year. Seasonal influenza viruses circulate
through the human population, and they spread easily from person
to person.
Avian influenza A H5N1, also known as bird flu,
is a devastating global outbreak in poultry. It's a pandemic for
poultry, but only causes rare, but severe, human infections and
currently does not spread easily from person to person.
A pandemic influenza virus appears in the human
population periodically, and avian influenza A H5N1 is a likely
candidate but it is not a pandemic virus yet. The next slide, slide
38, just is a note to say that these slides only represent our state
of knowledge currently and that it's a rapidly changing field.
And so the best thing to do is keep up to date
by keeping track of things on the CDC Web site and other Web sites,
and there is a list of resources for Web sites you can use to keep
current on pandemic and avian influenza issues.
And so with that, I thank you, and ask for questions.
Deb Havens:
Thank you, Dr. Bhat. And I think the second portion
of our presentation is going to be from Dr. Adam Cohen. Dr. Cohen?
Adam Cohen:
Yes.
Deb Havens:
OK. You can start.
Adam Cohen:
Great. Thank you very much. My name is Dr. Adam
Cohen. I work at the Division of Healthcare Quality Promotion at
the CDC. That's the group at the CDC that works with other groups,
such as the flu branch, on infection control issues.
I will start on slide number three and give you
a little bit of a background on infection control and then lead
into the specifics of infection control for flu.
The goals of infection control are manyfold.
We seek to define and identify cases, to stop the spread of disease,
both in facilities and in larger populations, to ensure safety for
personnel providing care, to confirm the effectiveness of infection
control practices, and to prevent inappropriate responses.
Slide four. There are some challenges to infection
control of respiratory pathogens, and that's that transmission can
occur by respiratory droplets or droplet nuclei. People can get
infected simply by coming near infected patients.
And many symptoms, as we heard in the last talk,
are non-specific. Recognition of the infection may be delayed.
Slide five. The approaches to controlling transmission
are not new, however. Isolation precautions to prevent the transmission
of pathogens are well-established. And I'll now quickly go through
some of the basic infection control practices, which we'll revisit
when we talk about the specifics for the different types of flu.
There are standard precautions which are recommended
for all patient interactions, and then there are transmission-based
precautions for specific pathogens. And there are three of those:
contact, droplet and airborne.
Slide six discusses standard precautions. This
also used to be called universal precautions. This includes constant
use of gloves and handwashing for any contact with blood, moist
body substances, mucous membranes, or non-intact skin. Gloves should
be removed and discarded immediately after completing a task and
hands should be washed every time gloves are removed.
The next three slides (seven, eight, and nine)
go through contact, droplet and airborne precautions. With contact
precautions, which are used for diseases such as shigellosis, Ebola,
and MRSA, include limiting patient movement, providing private rooms,
wearing disposable gowns and gloves when entering the patient room,
and continuing to wash hands. You can review the rest of that slide
later.
Droplet precautions, which are used for diseases
such as Neisseria meningitis, pertussis, and seasonal influenza,
includes using a face shield or goggles and a surgical mask, not
an N-95 mask. Patients should be separated by about one to two meters
or grouped with other patients with the same infection or colonization
status.
Negative pressure rooms are not recommended or
needed for droplet precautions.
The third type of transmission precautions are
airborne isolation. These are for diseases that are spread by very
small particles that remain infectious while suspended in the air,
such as tuberculosis, measles, and chicken pox.
With these patients, a negative pressure room
is recommended. The patient should wear a surgical mask, and an
N-95 mask should be used for personnel.
As part of standard precautions, a new section
was added on respiratory hygiene and cough etiquette. And this came
out of our experience with SARS. Slides 10 through 14 go through
the respiratory etiquette and cough etiquette.
I will let you read that on your own so that
we can get to the question and answer session, but these are commonsense
recommendations on how to prevent transmission through cough.
Slide 15 continues with other infection control
considerations, which are that healthcare personnel are advised
to observe droplet precautions when examining and caring for patients
with signs and symptoms of a respiratory infection and that these
measures should also apply to accompanying family or friends and
any other person with respiratory symptoms entering the facility.
Slide 16 discusses recommendations for physical
separation of patients. There have been some studies that suggest
that a proximity of less than three feet has been associated with
increased risk for transmission of infections through respiratory
droplets. Increasing the distance between infected patients and
others may decrease transmission risk.
Slide 17 reinforces that hand hygiene is very
important. It has been shown to reduce the incidence of respiratory
infections both in and out of the healthcare setting.
Slide 18 discusses why hand hygiene might be
important with flu. Influenza virus can survive on a variety of
surfaces at room temperature and moderate humidity. On surfaces
such as steel and plastic, the influenza virus can survive for one
to two days. On more porous materials, such as cloth and tissues,
it can survive for up to 12 hours.
So the good news on slide 19, however, is that
the virus can only be recovered on hands for about five minutes
after inoculation, and even then, only after contamination with
high viral titers. Therefore, alcohol-based hand rubs have a good
and rapid activity against influenza.
These data are indirect evidence that influenza
can be transmitted by contact but that hand hygiene, such as with
alcohol-based hand rubs, will easily address this route of transmission.
Slide 21 discusses a controversy within the infection
control world of how to treat influenza, particularly pandemic influenza.
It comes back to the discussion of the difference between airborne
and droplet transmission.
With droplet transmission, the contagious droplets
are propelled a short distance and come into contact with conjunctiva
or mucous membranes. They're typically large, greater than five
micrometers, and typically travel only a few feet. They do not reach
the lower airways.
And droplets, unlike with airborne transmission,
do not stay suspended in the air or travel distances.
With airborne transmission, the production of
infectious droplet nuclei can remain suspended in the air and travel
over distances. This is because they are smaller in size and they
do reach the lower airways.
The important point is that seasonal influenza
and what we know about influenza from previous studies, is that
flu is transmitted by droplet and not airborne. Therefore, droplet
precautions have been recommended by HICPAC and employed by healthcare
facilities for many years in the prevention of flu.
In slide 24 there is a discussion that several studies suggesting
that at least some component of flu transmission is through airborne.
Slide 25 is where we discuss the infection control
guidelines for the three types of influenza that Dr. Bhat discussed
at the end of his talk: seasonal, avian, and pandemic. There are
specific recommendations for each one.
Slide 26 discusses that with seasonal influenza,
which is the typical influenza that we see each year, droplet precautions
plus standard precautions are important for the duration of the
illness, which is generally five days from symptom onset in adults
with normal immune system.
Patients should also be housed in private rooms
with negative air pressure as much as possible and feasible, and
private rooms without negative pressure and cohorting are acceptable
options.
Slide 27 discusses our recommendations for avian
influenza. Patients with a history of travel within 10 days to country
with avian influenza and are hospitalized with a severe febrile
respiratory illness should be under evaluation for avian influenza.
And in addition to current standard precautions,
we also recommend airborne precautions. It is very likely that avian
flu, like most other flus, is transmitted through droplet. At this
time, we're evaluating the little data we have right now about the
transmission of avian flu. To be on the safe side, we currently
still recommend airborne precautions.
With pandemic influenza, the recommendations
are slightly different, and that's because in slide 28, early in
the pandemic, it may not be clear that a patient with severe respiratory
illness has pandemic influenza. Therefore, precautions consistent
with all possible etiologies, including a newly emerging infectious
agent, should be implemented.
Slide 29 starts discussing our recommendations
for infection control with pandemic influenza. Patients with known
or suspected pandemic influenza should be placed on droplet precautions
for a minimum of five days from onset of symptoms. That's similar
to the infection control recommendations with seasonal influenza.
However, with pandemic influenza, during procedures
that might generate aerosols, such as bronchoscopy, intubation,
and suctioning, we are recommending airborne precautions, which
include a negative pressure isolation room and a particulate respirator,
such as an N95.
We also recommend contact precautions and eye
protection.
Slide 31. With pandemic influenza we should also
consider the addition of airborne precautions for strains of influenza
exhibiting increased transmissibility during the initial stages
of an outbreak of an emerging or novel strain of influenza as determined
by other factors.
But if pandemic flu behaves like seasonal flu,
as we expect, then changing to airborne plus contact precautions
will add very little to control efforts since most of transmission
will still occur via large droplets.
In conclusion, a respiratory hygiene and cough
etiquette strategy will serve as the first line of defense against
all respiratory pathogens, including pandemic influenza, and should
be implemented as part of standard precautions.
Specific infection control recommendations for
pandemic and avian non-pandemic influenza will evolve as we learn
more. And our infection control strategies must be adaptable.
The last few slides discuss some of the specific
procedures that should be considered for causing aerosol and the
airborne precautions should be used for.
Thank you very much. I think at this point we
could open this up for questions.
Deb Havens:
All right. Thank you very much. I just want to
remind everyone that during the question and answer, our discussion
segment of the call which we are on right now, we please request
that everyone identify themselves by stating their name and the
location from which they're calling from and ask the question.
So I guess we'll open it up, operator.
Operator:
If anyone does have a question, you can signal
at this time by pressing star one on your touch-tone telephone.
If you're on speakerphone, please make sure your mute function has
been turned off to allow your signal to reach our equipment. A voice
prompt on your phone line will indicate when your line is open to
ask a question. Please state your name before posing your question.
Once again if you have a question, please press star one now. And
we'll pause for just a moment. Once again if you have a question,
please press star one now.
And we have no questions at this time.
Deb Havens:
I'll start off the questions. This is Debbie
Havens. And the first question I'd like to ask our panel is how
should a rural health clinic start setting up and preparing for
the flu season or for a pandemic or for avian flu?
Niranjan Bhat:
Well, this is Niranjan Bhat. I can start off
by saying that part of, part of the planning for a pandemic influenza
occurrence is to just increase your preparations for any type of
health emergency where you would expect a larger number of patients
and a larger severity, increase in severity of illness.
I think that the checklists help to kind of guide
you in terms of looking at all of the issues that would be relevant,
including surveillance and detection of the pandemic influenza virus
as well as in occupational health and surge capacity issues as well
as contacting and communicating with your local public health agencies
so that the support, including antivirals or vaccine, if they're
available, would be distributed.
A lot of the preparation just goes into finding
out what is your state pandemic plan, what stage is it in, who are
the people you can talk with to help you make plans, and just to
basically keep up to date.
I think that a lot of people take a sort of doomsday
scenario when thinking about a pandemic, and I would just make it
important to remember that a pandemic is not a situation where,
like a hurricane, where facilities are destroyed or roads are impassable
or even like a large snow storm.
It is a question of availability of people and
speed of services. And unfortunately in this era of just-in-time
supply, there is some fragility to the transport and delivery of
goods, including food. And so that's why people end up recommending
stockpiling of food and other essential goods.
Deb Havens:
Should we be stockpiling the medicines now?
Niranjan Bhat:
We would not recommend stockpiling antivirals,
specifically. This is something that we would hope that people will
understand in terms of the danger of having personal stockpiles,
mainly because, as has been demonstrated this season, resistance
of influenza viruses to antivirals can occur. And it's much more
likely when the unregulated use of these prescription drugs are
frequent.
And therefore, we really would recommend against
people having a stockpile because there is really a high risk for
inappropriate or inadequate treatment in the development of resistance.
It is something to think about to have just an
extra supply of non-prescription medications, including symptomatic
therapy, like pain relievers and fever, fever treatment. But also
keep in mind that, you know, a pandemic activity would come to a
community at a different time from other parts of the country.
And so while a pandemic across the globe may
last a few months, it would only come to a community for a few weeks.
And so it's not something that's going to be a long-term issue.
However, there is a possibility of second waves
that have occurred with previous pandemics. But usually those who
have been affected by the first wave are immune to the second wave.
Deb Havens:
In terms of treating the patients, if we do get
that wave of patients, is your advice, or would your advice be that
we'd be better off telling the patients to stay home and phone in
a prescription and not have them come into the office? Or have them
come into the office and perhaps have a quarantined area?
Niranjan Bhat:
That is a very good question. And it relies on
the ability of the clinic to triage or determine the severity of
the illness of the person. I think that it may very well be a good
idea for those with mild infections to stay home and consider home
treatment.
And in particular, since antivirals won't be
likely available for every person in the United States, and much
less the world, there's probably going to be a need for those with
mild infections and with a low risk for development of complications
to defer antiviral treatment.
As I said before, antivirals only really show
most benefit if they're begun within the first 48 hours of illness.
And what they do is mainly decrease the number of days of symptoms
by one day. This may have some benefit for reducing complications
due to a pandemic virus, but that is one issue.
In regards to whether a person would need to
stay at home versus come to the clinic, we are developing guidance
to help develop some guidelines for assessment as well as by the
public as well as by clinic providers to determine whether a person
needs to come in.
But we would expect that the types of complications
that occur from pandemic influenza would be similar to those occurring
with seasonal influenza but in greater frequency and severity. And
so a lot of the common sense directions in triage that we currently
use today for seasonal influenza could probably be used during a
pandemic situation.
And in terms of quarantining an area, it is advised,
even currently, in the post-SARS era, that clinics and emergency
rooms, during the respiratory season set off an area for people
with respiratory symptoms so that they can decrease transmission
to other patients.
Deb Havens:
Operator, do we have any other questions?
Operator:
We do have a question in the queue. Caller, please
state your name before posing your question.
Beth Harrison:
Hi. This is Beth Harrison from (ETMC) Fairfield.
The question we have is, is there any plan, federally or privately,
to increase manufacturing of flu vaccine just to increase our volume?
Niranjan Bhat:
Yes, this is Niranjan Bhat. I can answer that.
There is the hope and the plan to increase the production as well
as the demand for our seasonal influenza vaccine because it's felt
that the, if we can expand the capacity and the stability of the
influenza vaccine market that will help the vaccine manufacturers
to develop the ability and capacity to produce a pandemic vaccine,
should a pandemic occur. This is not intended to just generate money
for the vaccine industry. But it is to get to some stability.
And there have been gains in the influenza uptake
over the past several years. It's been complicated the vaccine shortages,
but, and supply issues. But that is a major component of the pandemic
influenza funding that Congress has allocated.
Deb Havens:
Operator?
Operator:
Yes, ma'am.
Deb Havens:
Do we have another question?
Operator:
We do not.
Deb Havens:
All right. This is Debbie Havens. I'll ask some
questions we received by email. The first is can either of you describe
the signs and symptoms of seeing it in birds, in the case of bird
flu? Like what do you look for in birds?
Niranjan Bhat:
Adam, I think I can take that, too, unless you'd
like to take it.
Adam Cohen:
Yes.
Niranjan Bhat:
Well, neither of us are veterinarians, of course,
and we at the CDC deal mainly with human health. But I do have some
experience with the veterinary side of things when working with
bird flu.
And so the signs and symptoms of avian influenza
in animals is primarily seen in domestic poultry. This is primarily
a disease of domestic poultry, chickens and turkeys and ducks.
And in chickens particular you'll see edema of
the waddles and combs as well as edema of the feet. You'll see cyanotic
waddles and combs and you'll see respiratory secretions. You'll
see diarrhea, and you'll see neurologic symptoms, including (sound
lessens), balance problems, and such.
And it is a very severe disease and a rapid disease.
It's almost 100 - the bird flu that's circulating in Asia and Europe
and Africa right now is a very severe disease in poultry. It causes
almost 100 percent fatality.
It has been seen to affect some wild migratory
birds. So you may hear about reports of wild swan or a crane being
found and tested and confirmed for influenza A H5N1. But influenza
H5N1 has not been detected so far in the Western Hemisphere, either
in domestic poultry or in birds or in wild migratory birds.
And it does infect mammals, such as horses or
dogs. But it has been shown to infect cats as well as humans.
Deb Havens:
Very good.
Male: Operator, do we have any other questions
lined up?
Operator:
We do not.
Deb Havens:
We have one minute left. Would anyone like to
address, either doctor, would you like to make one more point in
a wrap up? No.
OK. I'd like to thank the speakers and the call
participants. I'd also like to thank the Office of Rural Health
Policy for the call series.
We will be announcing the next call on the topics
shortly and will email all that information to those who have registered
for the call series. If you'd like to suggest a topic, we're always
interested in your ideas, and we welcome them greatly.
And for any future ideas, please email them to
info@narhc.org. I'd also like to encourage others who may interested
to register for the technical assistance call series at the ruralhealth.hrsa.gov/rhc/
Web site, and be sure to include your email address in order to
be notified by email or any future call or information that we have
to offer.
So I'd like to thank you on a beautiful day here
in Washington, D.C. and hope you've all learned something. I found
it informative and hope you can use the information in your rural
health clinics.
Thank you all.
Operator:
That does conclude today's conference. We thank
you for your participation. You may now disconnect.
END
|