Articles

The New Flu

September 10, 2019


I’m Gina Vild. I’m the Associate Dean for
Communications and External Relations at Harvard
Medical School. Thank you for joining
us here today. We’re going to be
taking questions at the end of the presentation. So certainly for those
here in the audience, if you’re watching us
through the livestream, please write your questions
in the YouTube and Facebook comments section. So it’s that time of
year again, right? It’s time to support others
to the season of giving, which you know if you were
at our last Talk in 12, we have many opportunities
here at Harvard Medical School. It may be time for
holiday shopping, and it’s certainly
time to think about how you can prepare yourself
for the upcoming flu season. How many here have
had a flu vaccine? Oh, we have really good
response to the vaccine. That’s excellent. Well, we’re going to be
talking a lot more about that in the next hour. Did you know that
one of the earliest reports of an
influenza-like virus came from Hippocrates
back in 1410? He identified it as a contagious
disease from northern Greece. Over the centuries,
as you probably know, there had been major
outbreaks of influenza, with the first modern
flu pandemic occurring in Russia in 1889. And that, of course, was
known as the Russian Flu. It reached the
continent just 70 days after it began, and
ultimately affected about 40% of the world’s population. I mean, think about that. That was before
we had air travel, and we actually researched
this to make sure that number was accurate. 70 days it took to
travel to the US. It wasn’t until the 1930s
that scientists finally isolated and identified
the virus that causes flu, and researchers began working
on creating a flu vaccine. You may already know
that last year’s flu season was one of the most
severe in recent history. 49 million people were estimated
to have become ill with the flu last winter. Close to one million
people were hospitalized with flu-related
symptoms resulting in an estimated 79,000 deaths. More than 150 of
those were children. If you haven’t been vaccinated
in preparation for this year’s flu, it’s not too late. There are clinics throughout
the Harvard community and the Boston area where you
can get a flu shot at no cost. Here’s the slide. You can see where Harvard
University sponsored flu clinics are being held,
and the website where you can access more information. And if you’re interested
in staying abreast of the progress of
this year’s flu, please visit the Centers for
Disease Control and Prevention website. And that website is
also on the slide. So what can we expect
from this season’s flu? How effective is
the flu vaccine? As you know, last
year’s flu vaccine was not particularly effective. And we’re going to learn more
about that and why and how they develop the flu vaccine. And what are the
treatments available to us? I’m pleased to
introduce Dr. Kuritzkes. He’s the Harriet
Ryan Albee Professor of Medicine at
Harvard Medical School and Chief of the Division of
Infectious Disease at Brigham and Women’s Hospital. In addition, he’s a member
of the editorial boards for several science
journals and serves as associate editor for the
Journal of Infectious Diseases. Please give him a warm welcome. [APPLAUSE] Thank you. Thanks very much. It’s a pleasure to have a chance
to talk to you this afternoon about the flu. And let me add my
welcome to all of you here in the amphitheater,
as well as those who are participating online. Before I begin,
let me just briefly acknowledge some potential
conflicts of interest. I consult for several
pharmaceutical companies, some of which are involved
in the development of antiviral drugs for the
treatment of influenza. So in this talk, I know many of
you are health professionals, and some of you have quite
sophisticated knowledge already about influenza
and viral infections. But in my talk this
afternoon, because we have a much broader audience
as well through the webinar, I’m going to be
relatively high level. And I’m happy to dive deeper
during the question and answer period if I didn’t get
detailed enough in my comments. So let’s start by
just asking, what is flu, when people say that
they’ve come down with the flu? Well flu is a respiratory
infection that’s caused by the influenza virus. So the formal name
for flu is influenza. And this is a virus that
is transmitted from person to person by tiny droplets
in the respiratory secretions from infected people. And it can be spread not
just because you happened to be near somebody when
they cough or they sneeze, but often if they
cough or sneeze, those droplets may land
on a surface like a table or doorknob. And then you touch that
surface and then touch your hands, your nose,
your mouth, or your eyes. And those droplets survive
in the environment. The virus survives in those
droplets in the environment for a period of time. And that allows for the
very efficient spread of the virus from one
person to another, and is why we see
epidemics of influenza. So how do you know if
you have influenza? Well the symptoms
of influenza are, in some respects, pretty
classic, and in other ways, very much like other what
we call flu-like illnesses. So the symptoms typically begin
with the sudden onset of fever, headache, muscle aches and
pains, and malaise, or just not feeling well. These symptoms are
often accompanied by cough and a sore throat. And what distinguishes
flu from a typical cold– a general respiratory infection
not due to influenza– is, first of all, the
severity of the symptoms and also their sudden onset. People really feel like they’ve
just been hit by a truck and can’t get out
of bed as opposed to the typical several day
progression of feeling a bit of a scratchy throat, and
then a little bit of fever, and a bit of a runny
nose, and so forth that is typical of having a cold. And these symptoms
usually resolve within about two to
five days especially in young healthy people, but
can take a week or longer to resolve and occasionally
can lead to more significant complications. Well what are some of
those complications? The most common complication
of influenza is pneumonia, and this tends to occur most
often in high risk individuals. And that includes people who
have underlying heart or lung disease, people who have
pre-existing conditions such as diabetes or kidney
disease, and then the elderly, particularly those
in nursing homes and in chronic care facilities. We also worry a lot about
influenza in pregnant women because, especially later
in pregnancy, their ability to take a full deep breath
is restricted somewhat by the large uterus
and baby inside that may hamper clearance of
respiratory secretions and predispose to more severe
pulmonary complications of influenza. Well how do you know
that you have influenza? How do we diagnose this? Interestingly, despite all
of the advances in laboratory testing– some of which
are quite significant– it turns out that good old
fashioned clinical judgment in the setting of an
influenza epidemic is just about as good
as a laboratory test. So in the middle
of a flu season, if you have the rapid onset of
the symptoms typical of flu, then there’s an 80%
chance that you have flu. And some of our rapid tests
are less sensitive than that at diagnosing influenza. So just a clinical
diagnosis alone is probably going to be right
in the appropriate context. Now we do laboratory
confirmation in many settings, especially in the
hospital where we’re trying to segregate people who
have influenza from those who don’t, because we
don’t want influenza to spread to other patients
who are still healthy. And nasal swabs can
be tested in the lab to detect the presence
of influenza virus. And it’s important to note
that these are nasal swabs, not a throat swab. A throat swab is pretty
insensitive for detecting flu. It has to be a swab
that’s inserted all the way into the
back of the nose, not terribly comfortable, but
very effective for diagnosis. The rapid tests can be
done in a doctor’s office, but they may miss up to
half of cases of influenza. They’re not terribly
sensitive tests. And that’s why I said,
in the right setting with the right symptoms, if it
seems like you have the flu, you probably do and
getting a rapid test isn’t going to help very much
in nailing down the diagnosis. But there are newer
tests more sensitive tests that we often refer
to as nucleic acid test because what they do is
actually detect the presence, not of viral
proteins or antigens, but the viral genome, the
viral RNA by PCR-based methods. And those can be done usually
in reference laboratories often in a hospital lab or
a commercial laboratory. And depending on how fast the
sample gets from the emergency room or the doctor’s
office to the lab, the results can be back
within one to eight hours. So not as rapid as an
office-based test, but still test results within a day. In contrast to a lot of
other infectious diseases, blood tests really play no real
role in diagnosing influenza. There is no blood
test for the flu. Sometimes a doctor might
get a blood test just to find out what your
white blood count is, but there isn’t a
way of diagnosing flu with a blood test. So we really don’t
rely on those at all. Well, if it’s not the flu,
then what might you have? And as I said before, the
common cold, which is usually caused by a different virus
that we know as rhinovirus, shares many of the
symptoms with influenza, but it’s usually
much less severe, especially the systemic
symptoms are less severe. And as almost
everybody in this room has had a cold at least
once in their life, you know nasal congestion is
really the predominant feature of what we would consider a
classical upper respiratory infection due to rhinovirus
where your head feels really foggy and cloudy or your
nose is all stuffed up and you have trouble sleeping. You may have cough, but
that usually develops later, as opposed to the early
and sudden onset of cough associated with the high
fever and headache that’s more typical of flu. There are a host
of other viruses that can also cause flu-like
illness, several of which occur in epidemic fashion, like
respiratory syncytial virus, or RSV, parainfluenza,
which is very much like flu, and adenovirus. And we’ve seen
adenovirus epidemics in the last couple of years,
but these are much less common than influenza. They tend to occur in
specific populations. RSV is much more of an
issue in younger children than it is in adults. It can be a problem in
immunocompromised patients. And adenovirus, classically,
we see that when large numbers of young
people are put together. For example, among
military recruits, adenovirus can be an
issue in training camp. This slide gives you a view of
what the influenza epidemic was like in the United States
during the 2017, 2018 season. And there are several features
that are worth pointing out. First of all, this looks
like any classic epidemic. It starts out with some low
level of sporadic cases, and then things
begin to pick up. And then suddenly, there
is this exponential growth in the number of cases that
eventually plateau and then things peter out. And if you look at the
x-axis here, these are weeks. And the weeks are numbered
by week of the year. So we start out in
the 40th week of 2017, which would be somewhere
around end of September, beginning of October. And you can see that
here, by December, things are really
beginning to pick up. And the peak occurs around
the sixth to eighth week. So in February, we saw the
peak of influenza activity in the United States, and
then that again tailed off. So that by 20 weeks into the
year, or roughly end of April, beginning of May,
we really were only seeing occasional sporadic
cases of influenza. The second thing
you’ll notice is that there are two different
colors here, yellow and green. And that’s because there are
two major types of influenza that circulate in any
year and infect humans. They are influenza type
A and influenza type B. Within these types, there
are many different subtypes. I won’t go into all the detail
about the various subtypes. The clinical disease
caused by influenza A and B is really
indistinguishable, but because they are different
viruses, the vaccine that we use has to contain
components that protect against influenza
A and components that protect against influenza B. And for the last several years– many years, in fact– it’s been typical that the
early peak in influenza activity is due to influenza
A as you see here. And then the later peak is due
to influenza B. In fact, it looks like they probably
coincided last year, but we usually see more
B activity straggling into the spring,
compared to influenza A. In addition to the
very large number of cases that
occurred last year, some things that were notable
about last year’s epidemic were that the peak activity had
shifted a little bit earlier into the year. For several years, we had
been seeing very late peaks in activity with
large numbers of cases still occurring in March. And this time, the peak
really occurred January, February and then, as
I said, tailed off. The other issue,
and we’ll talk more about that when I
get to the vaccines, is that there are usually
several different types of influenza A that circulate. And last year, the type
that ended up circulating was not the type that we
thought would be circulating, and the vaccine didn’t
do as good a job at protecting against
influenza A as had been hoped. So how do you protect
yourself from the flu? First and foremost are the
sort of basic principles of good personal hygiene. I mentioned that one of the
ways that influenza is spread is through these droplets
that can land on surfaces– the droplets we call fomites. And so avoiding touching your
hands to your face, your eyes, and nose, and mouth
when you’re in public, and washing your
hands before eating, and avoiding close
contact with people who are sick with
the flu is already an important way of
protecting yourself against influenza, as well
as against other respiratory infections. But really the thing that
everybody needs to do– and I’m so glad to see that
the vaccination rate here is was high as it is–
is vaccination. And even though influenza
vaccine is imperfect– none of our vaccines
are perfect vaccines– they do dramatically reduce
the risk of infection. And not only will they prevent
you from getting influenza, but by reducing the overall rate
of influenza in the community, there’s this herd effect
where the more people who are protected against flu,
the fewer other people who are likely to get
infected with the flu. It’s the same reason why it’s
so important that everybody be vaccinated against
measles, mumps, and other common
viral infections. And contrary to
what is occasionally written about in the
popular press or on the web, the influenza vaccine
is extremely safe. Severe adverse reactions
are extraordinarily rare, and the likelihood of ending
up with severe complications from influenza far exceed
the very, very low likelihood of having a severe complication
of influenza vaccination. Now as you heard in
the introduction, last year’s flu vaccine
was not all that great. It was about 40% effective,
but the effectiveness varied quite a lot depending
on which component you were talking about. And so as I mentioned,
there are typically a couple of different
strains of A that circulate. And last year, there was an
H3N2 strain and an H1N1 strain. I won’t go into all
the details about that, but you can see here that the
vaccine was only about 25% effective against H3N2. And since that was most of
the flu that circulated, that’s why the
overall numbers are knocked down so much when
you look at overall vaccine efficacy. But it was 65% effective
against the other influenza A, the H1N1 strain. And it was reasonably
effective, about 50% effective, against influenza B. So if you
take the average of all those, then it turned out to
be about 40% effective. So not great, but
certainly better than no protection at all. Now, who should receive
the flu vaccine? Everybody should
receive the flu vaccine. There’s really almost
never a medical excuse not to receive the
influenza vaccination. Flu vaccine is
recommended for all people who are six months or older. We can’t give the flu vaccine
to very young infants. It’s not been shown to
be safe and effective in that population. So we don’t vaccinate newborns. But after six months
of age, then everybody should get the vaccination. It’s also important to
realize it’s never too late to get the flu vaccine. We start vaccinating the very
end of September, early October as soon as the vaccine
stocks are released and are on the shelves in
the pharmacies, but if somebody
shows up in January and they still haven’t
gotten vaccinated, or somehow you missed
getting vaccinated and it’s January
or February, that’s not a reason not
to get vaccinated because if you remember
back to the slide looking at the epidemic, there
are still cases happening in March and April,
and maybe even into the first week of May. And so there’s no
reason not to become protected, even if it’s already
late into influenza season. Young children who get the
vaccine for the first time have to get two shots the first
year at least one month apart. And then once they’ve gone
through that initial vaccine series, then every
subsequent year, they only need to
get the vaccine once. And for all of the
rest of us, we only need to get the
vaccine on one occasion each year though, that’s the
thing, because the flu changes from year to year. There are many different
subtypes of A subtypes of B, and each year, the Centers
for Disease Control through their
surveillance network look at what kinds
of flu strains are circulating in human
populations around the world. And because flu seasons tend
to be six months out of sync in the northern and
southern hemisphere, they look at what’s
happening in tropical regions and what sorts of strains
might be in the circulation. Then they have an expert
panel, the American Committee on Immunization
Practice, come together with experts from the
Centers for Disease Control and essentially
try to guess which of these strains
that are circulating are most likely to be the
dominant strain, the epidemic strain for this
coming flu season. And that has to be done
sometime back in the spring because then they have to
tell the manufacturers which strains of flu they
need to start growing up to make vaccine. So that by the time it’s
ready to start vaccinating, there are adequate flu stocks. So it’s really a very
challenging, organizational, and logistical effort to
first gather the data, analyze the data,
make the predictions, And then have the companies that
are producing flu vaccine go into full scale
production in order to get this out to the public
in time for flu season. So once upon a time,
it was really very easy to talk about flu
vaccine because there was only a single
kind of vaccine, and it was what we call
the Trivalent flu vaccine. It was inactivated,
and that’s because it had two A components
and one B component, and the only vaccine that there
was that inactivated Trivalent vaccine. There are now
something like eight or nine different
kinds of flu vaccine. There is a vaccine that
has three components. Then there’s the vaccine that
has four components, which we call the Quadrivalent. It has an extra B component. There is a standard dose and
then there’s a high dose. The high dose has more flu
antigen in the vaccine, and it gives higher
levels of antibody, and in an at least one
large study, better levels of protection against
influenza in older patients, people over age 65. And then there is a
live virus vaccine. And then there is
a vaccine that’s made in the laboratory
instead of growing it in eggs and several
other different variants. And so there’s much
more choice of vaccine than there used to be. And curiously, although
all these vaccines are approved by the
FDA for use, there isn’t actually a recommendation
from either the CDC or from the Committee on
Immunization Practices on which vaccine is
best for people to use. And so although there
are some vaccines like the high dose
that are approved only for certain populations,
such as the elderly, there’s no recommendation that
you should use the high dose vaccine in the
elderly, that it would be inappropriate to use
the standard dose vaccine. Likewise, there’s the Trivalent
and the Quadrivalent vaccine, but there’s no recommendation
about whether you should get the three or
the four strain vaccine. At Brigham and Women’s Hospital,
we give out the Quadrivalent. And I suppose you could
argue that if three is good, four may be better, especially
if there’s another strain that could be circulating, but
there really aren’t firm data to argue that it’s better
to get the Quadrivalent than the Trivalent. And therefore, no
recommendation, because these recommendations
that come out of the CDC are always firmly anchored
in available data. So since you are
already all vaccinated, just a little bit
after the fact, but for those on the webinar
who may not be vaccinated yet, the best thing to do is to check
with your physician or health care provider about which
vaccine is best for you. Well, who shouldn’t
get a flu vaccine? They’re really a tiny
category of people. So as I said, very
young infants, infants younger than age 6 can’t
yet get the flu vaccine. Years ago, as some
of you may recall, this was I believe back
in the ’70s or early ’80s, there was an epidemic
of swine flu, and there was a big
effort to vaccinate as many people as possible. And a few people came down with
a neurological condition known as Guillain-Barré
syndrome and there– although there’s still a
big dispute about whether it was or wasn’t associated
with flu vaccine, it appeared at the time
that this was associated with the vaccination. And so since that time,
anybody who has developed Guillain-Barré within six weeks
of receiving a flu vaccine is recommended not to receive
subsequent flu vaccines. That is a tiny number of
people, probably only dozens. People who have had a history of
a severe reaction to influenza shouldn’t receive that again. That doesn’t mean if
you had a sore arm or you had a fever
for a couple of days and felt crummy, that
that was a reason not to get the vaccine again. I mean if you had a really full
blown reaction that landed you back in the doctor’s
office because of an allergic-type
reaction to flu, that you shouldn’t get re-vaccinated. And again, that applies only
to a tiny number of people. If you’re sick,
it’s probably not a great idea to get the
vaccine while you’re ill. Not because the vaccine is
going to make you worse, but because it will be hard to
know what is due to the vaccine and what is whatever it is
that you have at the moment, especially if you happen to
have a cold or a viral syndrome. And so it’s better to wait a
few weeks until you’re better and then get the vaccine. And then, another
common misconception is that because flu vaccine
is produced in eggs, it’s often thought that,
well, if I’m allergic to eggs, I shouldn’t get the vaccine,
and that’s not true. People with egg allergy can
receive any of the flu vaccines regardless of how
they’re manufactured. The likelihood of a
severe allergic reaction to flu vaccine just because
you have an egg allergy is extraordinarily low, and even
people with severe allergies can safely get the
standard flu vaccine. It’s just that in
those situations, it’s recommended that
the person be observed in the office for an hour
or so afterwards just to make sure they don’t have
an immediate allergic reaction. Well, what do you do
if you get the flu? The first thing is stay home. Please don’t bring it into
the office, don’t bring it into daycare, don’t bring it to
your co-workers or your family. Stay home until
you’re feeling better. And the hospitals
here all have policies of requiring that employees
who develop the flu stay home until their fevers have resolved
and symptoms have gone away. And then, although this
sounds like a cliché, you should get plenty of rest,
drink lots of fluids to stay well-hydrated. And then use either
acetaminophen or ibuprofen to treat the aches and
pains and the fever that may be associated with it. But there is more
specific therapy that’s available in the form
of antiviral medication. And these medications– and
I’ll review them in a minute– really can shorten the
duration of symptoms and can prevent serious
complications of influenza. The trick about using antiviral
medications to treat the flu, as with many types
of viral infections, is you really need to
take them early for them to have an effect. So for the flu drugs,
you really need to take them within the
first 24 to 48 hours. And then people feel
dramatically better within 12 hours
after taking them. I’ll tell a funny anecdote. Last year– we have a weekly
infectious disease conference, a Harvard-wide conference
on Wednesday mornings. And last year, one of our first
year fellows, Amir Mohareb, was giving a talk about the use
of anti-influenza medication for healthy adults. And while I’m sitting there
in the audience listening to this talk, I get a
text from my daughter, who was then 28 years old, saying,
I think I have the flu. What should I do? I said, well, go
see your physician to make sure you get
medication for this. So she went. They took a nasal swab. The rapid test was negative. So they sent the
test to the hospital for the more complicated test. And then they sent her home. And then they called her up at
the end of the day and said, yeah, it was positive,
here’s a prescription. That’s the wrong thing to do. Since the diagnosis really
could’ve been made clinically, if you think you have the
flu and if your doctor thinks you have the flu, you should get
the medication then and there and start it. You can always stop
it if it turns out you really don’t
have the flu, but you want to get that head
start because you really have this narrow window
to make a big difference in the duration of symptoms. In contrast to antiviral
medications, antibiotics– things like penicillin,
ampicillin, erythromycin, have no role whatsoever in
the treatment of influenza. The flu is a viral infection. Antibiotics treat
bacterial infections. And so the two have nothing
to do with one another, and there’s no point in
asking for antibiotics to treat the flu. Well, what are some
of the drugs that we have available for the
treatment of influenza? The one that we’ve
been using the longest is Oseltamivir, which
is also called Tamiflu. And this is a drug that
can be given by mouth, and it can be used
both to treat flu and to prevent flu in
household contacts. And it’s approved for
use in any age group, even in very young
children and in infants. And for treatment, we give
it twice a day for five days, and it’s highly effective. There’s another drug that’s
also been around for a while, called Zanamivir,
also known as Relenza. Unlike Oseltamivir, this
drug is very poorly absorbed. So it has to be
given as an inhaler, and that makes
its administration a little bit more complicated. It can also be used to
treat or prevent flu, but it can’t be used in
children younger than age five, mostly because they have
difficulty really using the inhaler correctly. And it’s not suitable
for people who have certain kinds of
respiratory conditions, like chronic obstructive
lung disease or asthma, because the aerosol can
irritate the airways and cause wheezing and
coughing and so forth. So if someone already has that
as an underlying condition, you wouldn’t want
to exacerbate that by administering the drug
through an inhaled route. And then Peramivir, which has
been available more recently, is a drug that can be
given intravenously. For most people, there’s really
not a reason to use Peramivir. The one advantage
is it requires only a single intravenous
administration, but we do use it in the
hospital if somebody is too ill to be given oral medication. It’s very helpful to have the
injectable form available. Now, this fall,
a fourth drug was approved for the treatment
of influenza, Baloxavir, which is also called Xofluza. And this drug is
the first new flu drug to hit the shelves
in several years, and it’s a really
exciting development, although exactly where it fits
in is not yet entirely clear. One of the reasons
it’s so exciting is it works by a completely
different mechanism than the three drugs
I just mentioned. And so, if the virus
were to become resistant to Oseltamivir or to
Zanamivir, Baloxavir would still be effective. In the clinical trials
that were done– and they were published in the
New England Journal of Medicine just at the end of September,
and the drug was approved in early October– Baloxavir of here was just
as effective as Oseltamivir. It requires only a
single oral dose. So that’s an advantage
over Oseltamivir potentially, although
Oseltamivir is now generic, and so likely
to be a lot less expensive than Baloxavir
will probably be. Baloxavir is also
active, as I mentioned, against not only
Oseltamivir-resistant flu, but also against
other kinds of flu, so-called avian
or bird flu, that has circulated occasionally. And so, one of the reasons
to have developed this drug was to have it on
hand in case we have a pandemic or epidemic
bird flu or other flus that we don’t see as often. But as I said, because
this is such a new drug, it hasn’t made it into
the CDC guidelines for treatment of influenza
for the current season. And we’ll have to see exactly
what place this drug has, except in settings where we know
that Oseltamivir resistance may be circulating. So let me end the formal
part of this session by summarizing that flu is a
seasonal respiratory illness caused by the influenza virus. The symptoms usually include
abrupt onset of fever, headache, muscle aches,
along with cough. The complications of
flu, such as pneumonia, are most common
in elderly persons and in people with
lung and heart disease. Influenza vaccine is
safe and effective, and everybody should
get vaccinated now if they haven’t already been. If you get the flu, stay home,
rest, drink plenty of fluids, and antiviral medication
such as Oseltamivir, Zanamivir, and now
potentially Baloxavir, can shorten the
duration of illness and should be started within 48
hours of the onset of symptoms. So with that, let me thank
you for your attention, and I’ll be happy
to answer questions. [APPLAUSE] Yeah, sure. [INAUDIBLE] Well, why don’t I start
off with a question that came from Facebook, and
this is from somebody in Egypt. Are there ways to naturally
stimulate the immune system to respond effectively to flu? That’s a great question. People have tried for many,
many years to find ways of non-specifically boosting
immunity to see whether it helps to protect against flu,
whether it’s through the use of vitamin C or– what it was it,
Acacia, or I forget. There are some natural
remedies people have thought of using, zinc tablets. And nothing really has
been shown rigorously to improve
influenza-specific immunity except for the
influenza vaccine. So while people continue
to search for approaches to boosting immunity
more generally, there really isn’t anything
that can be recommended now as being effective. Let’s see if there are any
questions here in the audience. Yes, please. Do you need a prescription
to stock up on the new one and have it at home just
in case you get sick, or do you have to get sick
and then get a prescription? Yeah, so all four of the
flu drugs that I mentioned are by prescription only. Oseltamivir has become
generic, not over-the-counter. It’s an interesting question
because of how people get flu in the
short time window, if there were enough
long-term safety experience with
Oseltamivir, in my opinion, it would make
great sense to make that available over-the-counter,
because people could then get treated right away. Of course, you’d want to
make sure people are treating the right thing right
away, which is a concern, but these drugs are
all by prescription. Yeah, sure. Do we know if the
vaccine administered here at the School of
Public Health was the– I have the word. Trivalent or quadrivalent? Yeah, quadrivalent or trivalent? Somebody knows. I don’t know, because
I work at the Brigham and not at the School
of Public Health. I’m sure the people
at health services know which one they were
administering, but I’m not– I don’t know off the top of
my head which one was used. And as I said, there’s
really no evidence that it makes a difference
which one you get, which is why the CDC hasn’t
come out strongly in favor. If they thought that the
quadrivalent was better, there’d be no good reason to
keep making the trivalent. And interestingly, the high
dose that’s used in older people is only available
as the trivalent. So it’s kind of
an odd situation. Let’s take another question from
the web, this one from Mexico. Now, if I have already had the
flu this year, should I still get the vaccine? Yes, you should. Because, as I mentioned, there
are several strains of flu that circulate at the same time. And if you already
had flu this year, it’s possible that you had flu
from one type of influenza A, but by getting the vaccine
you would still be protected against the other
influenza A type and against influenza B, or
possibly two types of influenza B if you get the quadrivalent. So there’s still a good
reason to get the vaccine even if you’ve already
had the flu this season. Yes. It sounds like the H and
the N number designations are only for influenza
A, not for B. And so, I’m wondering if there
are similar designations for B, and if so, why we
never hear of them. Is there more variation
in the A than the B? There is more variation in
A than B, but they all– H and N both stand
for proteins that are present on the
surface of the virus. The H is the hemagglutinin and
the N is the neuraminidase. And these two proteins are
the proteins against which the vaccine is directed. The vaccine induces
antibody formation, and these antibodies then
neutralize the virus by binding to those two proteins. It’s exactly the same
for B as it is for A. But you’re right, there are
many more varieties of A than B. And so we tend to
categorize them more according to the H and N types. I see. Thank you. Just there, you mentioned
that antibiotics play no role in the flu cure. So I want to know if the
infection of a flu virus would make people
more susceptible to the bacterial infect. Yes, it can. So the question is–
does influenza virus make you more susceptible
to bacterial infections? And absolutely. In fact, when people develop
pneumonia from influenza, one of the things
we worry about is that even if they start with
a pneumonia that’s due to flu, that their lungs can then become
super infected, that is, on top of the influenza
pneumonia, they can now develop a bacterial pneumonia,
and that can be quite severe. And it’s thought that in
the flu pandemic of 1918 that caused millions of deaths,
that a lot of the deaths were due to the occurrence
of bacterial pneumonia, either pneumococcal pneumonia
or staphylococcal pneumonia that was superimposed on
top of influenza pneumonia. But that’s not a reason to
start taking antibiotics. So you would only
take antibiotics if it was shown that you had
developed a bacterial pneumonia on top of your influenza. Wait for the microphone so the
people listening in on the web can hear. Aren’t the symptoms of
pneumonia and flu similar? So how would you know
if you have pneumonia? So that’s a great question. So they are somewhat similar,
and typically, the way to know is that a doctor
would get a chest X-ray after doing an exam. So the thing is– so
what’s common is cough, but shortness of breath
with flu is not so common. And chest pain, especially
pain taking a deep breath, or bringing up a lot
of phlegm, especially rusty-colored phlegm,
which is classic for pneumococcal pneumonia,
is not typical of the flu. So there are some signs,
but really, the way to diagnose that it’s actually
pneumonia and not just flu is by chest X-ray. Yeah. So why do people
with kidney disease have a risk for complication? That’s a great question. So the question was– why do
people with kidney disease– So many times, people who have
kidney disease, especially if they have advanced
kidney disease, where they are on dialysis, will
have other additional medical conditions like heart
disease and diabetes. And they’re generally
more susceptible to various infections
because they are in a generally
debilitated state, and their immune systems may not
be functioning quite as well. I mean, there’s a broad range,
of course, of kidney disease, and so not everybody
with mild kidney disease is going to be as affected. Let me take a couple of
questions from the web, and then we’ll go back
to the audience here. So a question from Nigeria is– how long does a single
flu vaccine protect for? So the vaccine
protects for a season. So if you get it in– in the northern hemisphere,
if you got the flu vaccine in October, you would
be reasonably protected through the end of April or May. The reason you wouldn’t be
protected the following year is because the viruses that are
in circulation in the next year may be different. There has recently been a
little bit of concern about if you get vaccinated
too early in the season, might the immunity have waned
by the very end of the season. So if you got
immunized in August, is that too soon to keep
you protected through April? But there aren’t clear
data on that yet. I’m going to take one
more from the web, and then we’ll get to
your question there. This one from here in Boston. If you have the flu, how do
you know when to see a doctor or be hospitalized? That’s a great question,
and really very important. It really has to do with
the severity of symptoms. And so you have to judge for
yourself just how sick you are. If you have fever and aches and
pains, you just feel miserable, but you’re not short
of breath, you’re able to get up out of bed
to go to the bathroom, you’re able to keep
things down in terms of drinking fluids and
having a little bit to eat, and if you take some
acetaminophen or ibuprofen and you begin to feel
better for a little while, it’s probably OK not to have
to go in to see the doctor. On the other hand, if you
have really high fevers, if you’re feeling really awful
and you just can’t get yourself out of bed, you
have a cough that is now making you
short of breath, and you’re beginning
to bring up phlegm, you’re having
shaking chills, those might be reasons to
go to the doctor, and particularly if
your symptoms don’t seem to be getting better. So why don’t we go ahead
with your question. [INAUDIBLE] Oh, OK. Thanks. What should you do if you
experience flu-like symptoms after receiving the vaccine? This is from someone
in California. So it’s not uncommon
to have a low grade temperature and a sore arm, and
maybe even some muscle aches. And the best thing to
do in that situation is just take some acetaminophen
or some ibuprofen, and the symptoms will
go away in a day or two. You don’t need to seek
any medical attention. But it is certainly
possible, if you are getting vaccinated
later in the season, that you get the
vaccine on Monday, and Monday night you
get sick with flu because you are
already incubating flu, and it was just bad
luck that you happened to have gotten the shot the day
that you came down with the flu because you’re in the
middle of flu season. In that situation, if you really
think that you’re coming down with flu, then you
should call your doctor and discuss with them what
the best steps would be. Another one from Colorado. Do you have any predictions
about how widespread flu will be this year? I don’t. If I did, I would probably be
in the stock trading business. So no, we really don’t know. It’s hard to predict
from year to year exactly how severe the
season is going to be. All I can say is everybody
hopes it won’t be as severe as it was last year. Sure. So if a person gets
the flu shot, what is the peak immunity, like
two weeks or three weeks after the vaccine, when a
person is optimally immunized, or is it shorter than that? No, it takes about two to three
weeks to have protection, yeah. I’ll take the question
up in the back there. Do we ever have to worry
about antibiotic resistance like with virals, like
antiviral resistance? Is that a thing? Yeah, that’s a great question. So the question is, do we
have to worry about resistance to our flu drugs? Absolutely. So we used to use drugs like
amantadine and rimantadine, which are a completely different
class of drug for treatment and prevention of flu. They were never
as terrific drugs as the ones we currently
have, because they also had some side effects. And now, all of influenza
A that circulates is resistant to those drugs. So we don’t use them anymore. Several years ago, the
H1N1 strain that circulated was Oseltamivir-resistant. And so for people who
developed severe flu, we were using either as
Zanamivir or Peramivir if they were hospitalized. And that’s one of the great
things about seeing a new drug with a different mechanism. So now that we have Baloxavir,
if it became apparent that the flu that
was circulating was resistant to Oseltamivir,
we’d have a fallback drug. Let’s see, another
question here. Should we be concerned
about a new flu pandemic? Well, I think epidemiologists
and public health officials are always concerned about
the possibility of a new flu pandemic. We live in an era
of globalization with international
travel, and something that breaks out in
one part of the world can very rapidly spread to
other parts of the world. I don’t think it’s something
we have to be nervous about. It’s just something we
have to be watchful about. And we would approach
a pandemic flu in much the same way that we
approach the annual epidemic flu, that is, make sure
everybody gets vaccinated, use antiviral medications
to treat people who are sick to help decrease the
period during which they’re shedding infectious virus,
isolate people who are infected by having people stay
home when they’re sick, and that would help curtail
the spread of an epidemic. Let’s see. Is it possible or conceivable
to develop vaccines without using eggs? Yes. And this was a question
from the Chan School here across the way. Yes– The Harvard T.H. Chan
School of Public Health. Yes, it is, and
there are, in fact, vaccines that are
flu vaccines that don’t require growth in eggs. There’s a cell
culture-based vaccine and there’s also a
recombinant vaccine. Those are sort of boutique
or designer vaccines, and the real question is– is there actually a
role for those vaccines? In somebody who has a
really severe egg allergy you might consider using
them, but again, the CDC recommends that
there’s no reason even people with egg allergy
can’t get the standard flu vaccine. And there are many
other vaccines outside of influenza that are developed
without the use of eggs, the measles vaccine, hepatitis
vaccine, for examples, is a recombinant vaccine. And then, lastly,
what should you do if you experience
flu like symptoms after– oh wait, no, I’m sorry. I answered that one already. I got them shuffled. [INAUDIBLE] One more question. Yeah, sure. Do you know why the flu
occurs during the months that it does every year? Well, that is a great question. And we see a lot
of illnesses that are seasonal in various ways. And the best arguments for
why flu occurs when it does is that although flu is
spread person to person, it’s not the most highly
contagious virus that we have. It’s not like a measles
virus, for example, which is incredibly contagious. So when people are in closed
settings, more indoors, not outside as much,
there’s more opportunity for person-to-person
transmission. So it’s not just influenza,
but a lot of other things we see more commonly in the
wintertime than in the summer, and they generally involve
person-to-person transmission like that. There’s some thought that
maybe the general stress of cold weather might have some
adverse effect on immunity, broadly speaking, and that could
make people more susceptible. Or, as you know, if
it’s a really cold day and you go outside, your
nose starts running. So the normal
clearance mechanisms that protect the respiratory
tree from pathogens may also not be functioning
as well in the cold as they do when it’s warmer out. But you can see epidemic
flu in the summertime. Several years ago, we did
have an atypical season, where there was a late
flu that occurred. It was most prominent in young
people, especially adolescents and young adults. And that happened in
June, July, and August. So we don’t know
really why, but we can come up with some
pretty good explanations for why it might be. Hi. How do they determine
the incidence of flu since so many people do
not go to the hospital? Are those estimates or
are they actual numbers and the actual incidence
is far greater? Right. So that’s a great question. So influenza isolates are
portable to the local health departments. So if somebody gets a
flu test done in a lab and it’s diagnosed,
then that’s supposed to be reported to the
Department of Health, and they keep a tally, and the
CDC collates those numbers. And the data I showed you
were for actual isolates, not cases of illness. But in addition, the
CDC has sentinel sites around the country where
they collect information on what they call
influenza-like illness, or ILI as they abbreviate
it, and really, they are estimating what the
actual total number of cases of influenza was in any
year based on reports of influenza-like illness
from these sentinel centers, and from state and territorial
health departments that report to them. Thank you so much. You’re very welcome. Thank you. [APPLAUSE]

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