World Health Day

Just a quick post for world health day:

Flu Hits 90 Million Children Under 5 Each Year

Global tally also includes 20 million kids with flu who develop potentially deadly pneumonia

FRIDAY, Nov. 11 (HealthDay News) -- Although it can be prevented with a vaccine, roughly 90 million children worlwide who are younger than 5 get the flu each year, resulting in about 1 million hospital admissions, a new study indicates.

Published in the Nov. 11 online edition of The Lancet, the research also revealed that flu-related pneumonia claimed the lives of up to 111,500 children in 2008. According to the report, 99 percent of these deaths occurred in developing countries.

CLICK HERE TO READ REST OF STORY.
Rather depressing, isn't it?

Medical News Today: Flu Vaccine Protects Pregnant Woman's Baby And Does Not Cause Miscarriage

I would suppose that this should go in the "Well, of course" column to rational people grounded in reality, however there has been some legitimately confusing studies that should be addressed.  I for one am glad they they were studied in a rigorous and methodical manner instead of whatever quackery and woo woo the anti-vax pro-disease nutters seem intent on.

Apart from protecting a newborn infant from flu for four months, the flu vaccine does not raise the risk of miscarriage, Kathleen Neuzil, MD, member of the Infectious Disease Society of America's Pandemic Influenza Task Force explained at their 49th Annual Meeting. Various presentations at the meeting are showing that pregnant mothers are getting the message not only about the flu shot's importance, but also its safety.

A newborn whose mother was not vaccinated is particularly vulnerable to flu because he/she is more likely not to be born with protective immunity and cannot be vaccinated for at least six months. A newborn who becomes infected with influenza is at a higher risk of complications, and even death, compared to older humans.

Dr. Neuzil, MD, who is also clinical professor in the School of Medicine at the University of Washington, Seattle, said:

"Pregnant women are understandably concerned about protecting their unborn babies, which makes it all the more important for them to understand that getting a flu shot during pregnancy is an important way to protect the baby, as well as themselves. These new data on the safety and effectiveness of these vaccines is reassuring, and the increasing number of pregnant women receiving the vaccine affirms that women are hearing the message about the vaccine's benefits."

CLICK HERE TO READ REST OF ARTICLE.

Harpocrates Speaks: Speaking of Flu

So yesterday I made a post about a CDC re-evaluation of their flu model.  It seems that Harpocrates Speaks also covered this story.  But as usual, Todd went into a bit more detail, and I wanted to get that info out there (although I find it funny that both he and I keyed on very similar ideas in that post.  Almost as if the anti-vax pro-disease nutters are predictable in their lies).  From his post on this, if you scroll down a bit, he starts:

Speaking of the Flu

While we're on the subject, as temperatures drop, the air becomes drier and people start to congregate indoors more frequently, flu season starts to ramp up. Conditions are becoming ripe for transmission of the virus, and hospitals are places where we really cannot afford to spread the flu. There are a lot of individuals whose immune systems are less able to cope with infection, so even illnesses that might be mild in a healthy individual may become life-threatening. Whether the patients are walk-ins or in for long term care, children, adults or the elderly, it is vital for hospital employees to be vaccinated against the flu.

I'm not just talking about the doctors and nurses, here. I mean everyone that works in the hospital. At the very least, anyone who spends any amount of time in a patient area (waiting room, exam room, elevators, hallways, stairwells, lobbies) should be immunized if they have no medical reasons to the contrary. Hospitals and their employees should take steps to protect the health and well-being of their patients, and that includes taking measures to reduce the risk of infection.

I decided to take a look online to see if I could find any recent reports of vaccine rates among hospital employees and stumbled upon a survey of Maryland Hospital Healthcare Worker Influenza Vaccination (PDF). This was a self-reported, web-based survey of Maryland hospitals looking at total number of employees who received a vaccine, number that exempted out for medical reasons, number that exempted out for religious reasons and number that declined immunization but did not provide a reason, compared to the total number of employees at the hospital. Some hospitals had mandatory immunization policies with consequences for non-compliance (such as loss of privileges or even being fired), some had mandatory policies but no consequences for non-compliance and still others had no vaccination policy.

READ THE REST OF THE POST HERE!
Good charts, graphs, and actual data there as opposed to simple assertions.

CDC Actually Follows Scientific Methods

The CDC has released a correction to one of their reports.  Granted, it is a post hoc release, but the thing about it is that the CDC has actually revised the estimate because they realized their mistake, and they are honest about it.  This is really the greatest strength of science.  To refine things and get better results as information, methods, and knowledge evolves (see what I did there?).  I have never seen an anti-vax pro-disease nutter actually re-evaluate their position, no matter how much data is actually presented to them.

So here is the CDC Press release (emphasis mine):

Notice to Readers: Revised Estimates of the Public Health Impact of 2009 Pandemic Influenza A (H1N1) Vaccination

In the May 20, 2011, report, "Ten Great Public Health Achievements --- United States, 2001--2010," on page 621, preliminary estimates of the impact of public health interventions during the 2009 H1N1 pandemic were presented as follows: "These public health interventions prevented an estimated 5--10 million cases, 30,000 hospitalizations, and 1,500 deaths (1)." These estimates were derived using combined data from two sources: 1) an unpublished CDC model for estimating the impact of the 2009 H1N1 pandemic influenza vaccine on averting cases, hospitalizations, and deaths during the 2009--10 influenza season and 2) a model for estimating the impact of antiviral treatment in averting hospitalizations and deaths during the 2009--10 season (2). As a result of a programming error, the model used to estimate the impact of vaccination did not adequately adjust for the decreasing risk for disease as the pandemic progressed, and thus the impact of vaccination was overestimated.

The corrected estimates for the combined impact from vaccine and antiviral treatment are as follows: 713,000 to 1.5 million cases, 12,300 to 23,000 hospitalizations, and 620 to 1,160 deaths averted. Of these, 713,000 to 1.5 million cases, 3,900 to 10,400 hospitalizations, and 200 to 520 deaths were averted as a result of the vaccination campaign (CDC, unpublished data, 2011), whereas the use of influenza antiviral medications is estimated to have prevented another 8,400 to 12,600 hospitalizations and another 420 to 640 deaths (2).

It is important to note that the error does not involve nor pertain to the effectiveness of the 2009 H1N1 vaccine, nor to estimates of the burden of the 2009 H1N1 pandemic, which resulted in approximately 43 million to 89 million cases, 195,000 to 403,000 hospitalizations, and 8,900 to 18,300 deaths, including 910 to 1,880 deaths among children aged <18 years, during April 2009--April 2010 (3). CDC-supported evaluations have shown that the vaccine was effective in preventing influenza medical visits during the pandemic (4). However, because there was early widespread circulation of the 2009 H1N1 virus, many persons in the United States became ill before vaccine was available.

CDC continues to work on developing and evaluating statistical models for estimating the impact of influenza vaccination in order to develop better programs and ways to monitor the impact of those programs. CDC expects this work might lead to future publications that provide additional impact estimates.

References

1. CDC. Ten great public health achievements---United States, 2001--2010, MMWR 2011;60:619--23.
2. Atkins CY, Patel A, Taylor TH Jr, et al. Estimating effect of antiviral drug use during pandemic (H1N1) 2009 outbreak, United States. Emerg Infect Dis 2011;17:1591--8.
3. Shrestha SS, Swerdlow DL, Borse RH, et al. Estimating the burden of 2009 pandemic influenza A (H1N1) in the United States (April 2009---April, 2010). Clin Infect Dis 2011;52:S75--82.
4. Griffin MR, Monto AS, Belongia EA, et al. Effectiveness of non-adjuvanted pandemic influenza A vaccines for preventing pandemic influenza acute respiratory illness visits in 4 U.S. communities. PLoS One 2011;6:e23085.

It's refreshing to see that there is a scientific method being adhered to.  If nothing else, that should be a reason for you to actually listen  to the CDC over the dogmatic denialists of the anti-vax pro-disease movement.

The Vaccine Times: Universal Flu Vaccine Another Step Closer, But Still Far

This is exciting news, even though we still have a long way to go.  I suppose that even though this aligns with one of the goals of the anti-vax pro-disease nutters (i.e. fewer vaccines), I bet they will still find a fault in this line of research as well.  One of the hallmarks of their irrational thinking and poor logic is that nothing will ever make them happy.  I think one of the cool things about this research is that our understanding of molecular level evolution led us down this path.  Here we consistently hit on two of the most irrational denialisms on the planet in one post!

On the Apr-Jun 2011 issue of  The Vaccine Times we reported on a new flu shot being tested which could do away with our need for yearly flu shots.  The vaccine candidate, called VAX102 is based on an antibody called F16 which can target a common protein shared by all Influenza A viruses which are the most virulent and the most prone to mutation influenza viruses.

Recently U.S. scientists are reporting the finding of a new antibody which can tackle 30 of the 36 known strains of H1N1 (a virus of the A type) flu virus. The newly discovered antibody, called CH65, can stick to the surface part of the flu virus known as hemagglutinin which mutates every season, forcing the formulation of a new vaccine every year.

CLICK HERE TO READ THE REST OF THE ARTICLE.

Vaccine Times: Flu kills 602 Britons in 2010

Just a straight copy/paste from Vaccine Times.  I have highlighted the item of interest though.  Again, this is not some ignored nation in Africa, but one that is supposedly modern!

The 2010 flu season has left quite a mark in the United Kingdom. The UKs Health Protection Agency (HPA) reports that 602 Britons have died of it this past season. That makes it deadlier than the 2009 swine flu pandemic which claimed the lives of 474 Britons. However, the swine flu claimed the most lives this year as well, with a total of 562 deaths due to it. That lead to the majority of victims (415) being in the age group of 15-64. Forty-five of those that died were children under 14, and 9 were pregnant women.

Information on vaccination history was available for about half of the fatal cases and almost 75 % (229/307) had not received the flu vaccine this year. Among children, there were 25 reported deaths in those aged five to 14 years, 16 in children aged between one and four and nine in children less than a year old. A further 91 probable cases are still under investigation to confirm flu as the cause of death.

Hopefully you and your loved ones will keep in mind all these individuals as you have an opportunity to get a flu vaccine this year.

Universal Flu Vaccine?

The Guardian is reporting a new flu vaccine that could be a great boon.  When I first saw this story, I was quite excited about it.  Now that excitement is quite a bit more reserved.  I read the article, and it seems like the media is at its headline grabbing tricks again.  While this study shows promise, I think it is much too early to make any definitive proclamations about this vaccine.

Vaccine Times covered it quite well:

Nevertheless, I must advise caution with this news. First, a red flag must always go up whenever we encounter “science by press release”. The author has sent her results to a scientific journal; the paper hasn’t even been peer reviewed and published yet, but they are already giving interviews to the media. That is worrisome to me; not a deal-killer in and of itself, but a red flag nonetheless.

Second, the study is tiny, only 22 participants, and the control group didn’t even receive a placebo, or a regular flu shot for comparison; I don’t see how randomization can be properly achieved with such small numbers either. Also, the supposed benefits are not clearly quantified. We are being told that “fewer” vaccine recipients got the flu than non-vaccinated people. Exactly how many “fewer” are we talking about? How much variance can be chalked up to pure chance when the sample size is so small? We are also told that the vaccinated people had “more” T-cells and that they were “more activated”. The same questions apply here; what does “more” mean exactly and how does that relate to actual flu infection rates? We’re not told, thus another red flag.

CLICK HERE TO READ THE WHOLE ARTICLE.

Vaccine Times: 3 dead of the flu in Los Angeles County

And it starts.  Now, these are still small numbers of people, and there were some underlying health concerns, but it still doesn't lessen the impact of someone's death.  I just want to reiterate that you should get your vaccine for this strain.  It's available, and poses minimal risks (less than the disease itself, which is the entire point!).

3 dead of the flu in Los Angeles County

On January 14, 2011, in ALL POSTS, Influenza (Seasonal), VACCINE PREVENTABLE SUFFERING, by Leart Shaka 

 

Los Angeles county has just reported its first 3 flu related deaths of the 2010-2011 flu season, including a 4-year-old boy, a 28-year-old woman and a 48-year-old man. All three died from a vaccine preventable strain of the virus, although it is no immediately clear if they were vaccinated. The adults were both obese, putting them in one of the at-risk groups along with the very young, elderly etc. On average LA county records about 1,000 deaths per flu season.

It is not too late to get the flu shot given that the flu season can last as long as May. According to the CDC recommendations, every person over 6 months of age should protect themselves via the annual flu shot. Get yours today.

Vaccine Times: 4-year old NY boy dead of flu-related pneumonia

Again, if the anti-vax pro-disease nutters had any empathy, they would be at every single one of these funerals...  Instead, folks like us who know what real science says about vaccines mourn the unnecessary loss of life.

4-year old NY boy dead of flu-related pneumonia

A 4-year old New Rochelle boy has died of a flu-related pneumonia infection, according to the Westchester County Health Department. The boy fell ill in November; he was previously healthy and had not not received the flu vaccine this year.

“Any death is tragic, especially in one so young,” said Dr. Cheryl Archbald, acting commissioner of health. “The best protection we have against influenza is the annual flu shot, which is recommended for individuals six months of age and older.”

The flu sounds innocuous however, in some instances it can lead to life-threatening complications, pneumonia being one of them. Vaccination is the best protection we have against the flu. Please refer to the CDC website about the flu, or my previous FAQ blog entry about it.

Our hearts and thoughts go to the family of the little boy; we are very sorry for your loss.

Vaccine Central: Flu vaccine safe to administer to those with egg allergies

The excuses for not getting your flu vaccine are getting fewer and fewer.  Just get the shot, and prevent suffering for yourself and those around you!

Flu vaccine safe to administer to those with egg allergies

New guidelines by the American Academy of Allergy Asthma & Immunology say that individuals with egg allergies can safely receive the flu vaccine, without a skin test being performed first. Flu vaccines are grown in chicken eggs, which raised concerns about possible allergic reactions to residual egg protein. Up to now, precautionary steps were taken, which included vaccine skin testing, administration via a 2-step graded dose challenging (10%, followed by 90% of the age appropriate dose after a brief observation period), or stepwise desensitization.
This latest AAAAI paper  ”offers guidance in how to evaluate and treat the patient with egg allergy who desires influenza vaccination, and outlines the latest evidence based approaches to successfully administer the vaccine.” According to the position paper:

Conclusion There has been tremendous growth over the past year in demonstrating that TIV (and H1N1) are safe for egg allergic individuals to receive. While a few concepts bear further study, such as the safety of these vaccines in individuals with severe allergy to egg, it appears that most egg allergic patients can safely receive influenza vaccination if desired. While no particular approach to administering the vaccine has been shown to be the safest and most effective, several methods for providing this service exist. Providers should no longer withhold the vaccine on account of a patient’s egg allergy, and should feel comfortable selecting one of two strategies we outline for administering the influenza

Vaccine Central: Everything you ought to know about the flu

It's always good to be informed about the disease you are trying to prevent.

Everything you ought to know about the flu

Well, not exactly everything, but a lot.


What is “the flu”?
Influenza, or “the flu” is an extremely contagious respiratory illness caused by influenza A or B viruses. Flu appears most frequently in winter and early spring. The flu virus attacks the body by spreading through the upper and/or lower respiratory tract. There are 3 types of flu viruses, A, B and C which can cause the flu, and new strains (especially the A type) evolve every few years.
Type A viruses are responsible for major flu epidemics every few years. Type B is less common and generally results in milder cases of flu. However, major flu epidemics can occur with type B every three to five years. There is a third type of virus, C, which also can infect but does not produce flu symptoms.
What are the symptoms/effects of the flu?
Besides generally making one feel miserable, here is a list of some of the most typical flu symptoms/effects.

• Headaches
• Severe aches and pains in the joints and muscles and around the eyes
• Cough
• Respiratory congestion
• Fever
• Chills
• Fatigue & exhaustion
• Severe flu can lead to pneumonia
• Sore throat and watery discharge from your nose
  

Are there any complications that can arise from the flu?
The most common flu complications include viral or bacterial pneumonia, muscle inflammation, and infections of the central nervous system or the sac around the heart. Other flu complications may include ear infections, sinus infections, dehydration, and worsening of chronic medical conditions, such as congestive heart failure, asthma, or diabetes.
Those at highest risk for flu complications include adults over 50, children ages 6 months to 4 years, nursing home residents, adults and children with heart or lung disease, people with compromised immune systems (including people with HIV/AIDS), and pregnant women.
How does flu spread?
The flu is spread from person to person through respiratory secretions and typically sweeps through large groups of people who spend time in close contact, such as in daycare facilities, school classrooms, college dormitories, military barracks, offices, and nursing homes.
Flu is spread when a person inhales droplets in the air that contain the flu virus, make direct contact with respiratory secretions through sharing drinks or utensils, or handle items contaminated by an infected person. In the latter case, the flu virus on your skin infects you when you touch or rub your eyes, nose, or mouth. That’s why frequent and thorough hand washing is a key way to limit the spread of influenza. Flu symptoms start to develop from one to four days after infection with the virus.
Will one catch the flu if one goes out in the cold or gets wet by cold rain?
No. The flu is a viral infection; you need to come in contact with the flu virus to get infected. Feeling cold or being wet does not give you the flu. It might give you a runny nose though and other symptoms that may be reminiscent of the flu, but it does not cause a flu infection.
What are the symptoms/effects of the flu vaccine?
The most common side effects of the flu vaccine (both inactivated and LAIV) include mild:

• Swelling at the site of the injection (inactivated only)
• Headache
• Cough
• Body ache
• Fever

When should one get the flu vaccine?
As soon as it is available.
How many types of flu vaccines are there?
There are two types of flu vaccine. Inactivated and LAIV. The inactivated vaccine is given as a shot, generally in the arm, while the LAIV version is a nasal spray. The main difference between the two is that the inactivated, or the shot, contains dead viruses, whereas the LAIV version contains alive, but extremely weakened, viruses. Because of that, the spray is expected to be more effective in inducing an immune reaction than the shot.

Why is the flu vaccine different every year?
Two of the three flu viruses are responsible for causing flu, type A and type B. Type A has 16 subtypes, while Type B is not categorized by subtypes.  They both can mutate, especially type A which results in new strains every few years. Every given year, any combination of various strains of the various subtypes of A and of Type B can be in circulation and causing flu.
Every given year, both the LAIV and Inactivated vaccine contain three strains of influenza virus that are chosen each year based on what scientists predict will be the circulating viruses for the flu season. Given the long production times, it is impossible to know for sure which strains will be prevalent in the upcoming season, so every year scientists have to do their best to predict what they think will be the prevalent strains. Usually this process is done months ahead of the actual flu season. This is why the flu vaccine is different each year, and why we have to get re-vaccinated each year.
Which strains does the 2010 vaccine protect against?
Every year, the flu vaccine, protects against 3 specific strains of viruses that cause flu. The 2010 vaccine protects against two A viruses and one B virus. This year the vaccine protects against these 3 strains:

• an A/California/7/2009 (H1N1)–like virus (Swine Flu)
• an A/Perth/16/2009 (H3N2)–like virus
• and a B/Brisbane/60/2008–like virus

Can you get the flu from the flu vaccine?
No! You cannot get the flu from the flu vaccine. You may, however, experience some flu-like symptoms, which can be experienced from any vaccine in some cases and doesn’t have anything to do with the actual disease you’re being inoculated against.
How effective is the flu vaccine?
The effectiveness of the flu vaccine depends on the strains in circulation and the strains the vaccine prevents from. When the vaccine viruses and circulating viruses are well-matched, the vaccine can reduce the chances of getting the flu by 70% to 90% in healthy adults.
Can you get the flu, even if you get vaccinated?
Yes. Firstly, as we already saw, the 3 strains in the flu vaccine have to be guessed in advance of the flu season. If there is a good match between the predicted strains and the actual strains in circulation, the vaccine will provide good protection. On the other hand, even if there is a perfect match, no vaccine is 100% effective, so even then a person who got vaccinated may still develop the flu. However, in general, people who are vaccinated experience milder symptoms than the non-vaccinated ones.
Who should get the flu vaccine?
Except for high risk groups that are advised to skip the vaccine, it is recommended that everyone over 6 months of age should get the flu vaccine.

Who should not get the flu vaccine?
Anyone with a severe allergy to eggs or egg products should not get a flu shot. Other people who should not get a flu shot include:

• Infants under 6 months old.
• Anyone who has had a severe reaction to a past flu shot or nasal spray.
• Someone with Guillain-Barre syndrome.
• People with moderate to severe illness with a fever; they should be vaccinated after they have recovered.
  

How Long Am I Contagious After I Get the Flu?
You are contagious for up to seven days after the onset of the flu, although the flu virus can be detected in secretions up to 24 hours before the onset of symptoms. This means you might transmit the flu virus a full day before your flu symptoms begin.
In young children, the flu virus can still be spread in the secretions even into the second week of illness.
How Can I Prevent the Flu?
To prevent the flu, be sure to keep your hands clean — making sure to wash them frequently to remove germs — and get a flu shot. The CDC develops a flu vaccine based on the type A strain that they believe will be most prevalent in the coming flu season. This is the vaccine you get with the annual flu shot or FluMist nasal spray.
Give me some statistics please?
-Every year during flu season, 1 in 20 Americans will contract the disease. Some years incidence can be as high as 1/5.
-Annually there are about 200,000 hospitalizations and an average of 23,600 annual deaths from the flu  in the US alone.



Sources
WebMD
Flu.gov

CDC Flu Website
World Health Organization Influenza Page

Why the epidemiology of swine flu matters

From ScienceBlogs:

If you are hesitating to be vaccinated for swine flu this year, perhaps this post will help you make up your mind. If it does, I hope it pushes you to get vaccinated, but whatever persuasion we attempt here will only be from a recital of what we know of the epidemiology of this pandemic. Because it is the different epidemiology that is the main feature, not the clinical characteristics or the virulence of the virus. So far this looks pretty much like a standard influenza A virus -- except for the epidemiology. Since I'm an epidemiologist, you might expect me to think this is important, and I do. Epidemiology is the public health science that studies the patterns of illness in populations. One kind of pattern we study is who is getting sick. And it is a change in this pattern that is one of the big differences between a pandemic strain and a seasonal strain.

Pandemic strains have a greater tendency to infect and make sicker much younger victims. In seasonal influenza it is the over 65 age group that contributes most of the serious illness and deaths, but with pandemic strains (not just the current one), lack of immunity in the population makes those under age 65 a bigger target and they sicken and die proportionately more than in a non-pandemic season. And that's exactly what we are seeing this year. The story that made the headlines on Friday was that 19 more pediatric deaths were added to the pediatric death toll in week 39, although not all of these children died in that week. The dates of death for the 19 stretched between July 19 and October 3 because of the way the tally is done. Starting in the 2003 - 2004 flu season deaths from influenza in people below the age of 18 became a nationally notifiable disease, reported to CDC through state epidemiologists. Each state has its own way of ascertaining the number. Some states are more complete and more timely than others, so notifications that come in a particular week can, and do, represent deaths that occurred over varying time periods, as in the instance of the 19 added this week. Still, it is clear that the young population is being hit particularly hard in comparison to the last three years for which we have data. 76 have died from swine flu since it made its first appearance in April, and 29 of those deaths have come since August 30, i.e., 29 in 5 weeks and those 5 weeks are extremely early in the flu season. In fact they occurred before the official administrative flu season even started (week 40).

The pattern of pediatric deaths and its difference from previous years is dramatically shown in this graph from CDC's weekly flu report:

The green bars are pediatric deaths from seasonal flu. You can see that in green bar terms, this flu season, which was not as bad as the previous year, was pretty typical. But this year, unlike previous years, there was a second flu season that started just as the usual one was finishing (the middle hump). We remarked on this back in July. Then there was a lull (we don't know why) and now we are into flu season and we see a third set of bars.

If you aren't in the pediatric population, here are some more patterns that may help convince you that getting vaccinated is a good idea. This comes from the Emerging Infections Program (EIP), another part of the multicomponent CDC flu surveillance system. These are lab confirmed influenza related hospitalizations in 60 counties in 12 metro areas of 10 states (San Francisco CA, Denver CO, New Haven CT, Atlanta GA, Baltimore MD, Minneapolis/St. Paul MN, Albuquerque NM, Las Cruces, NM, Albany NY, Rochester NY, Portland OR, and Nashville TN). It's a passive surveillance system where the data are obtained by record review of lab and hospital admissions databases and infection control logs. Each panel is an age group, with the top being babies and toddlers and the bottom one people over age 65 (you can see the original here if this is too small).

These are cumulative incidence rates. Think of them, at each week (the horizontal axis), as the chance that you will have gotten the flu by that time this year, i.e., if you look at week 37 the height of the curve reflects the probability that by week 37 you would have gotten flu at sometime before that (not necessarily that week). Obviously the curve can only go up, since it is cumulating (adding onto the pile of previously lab diagnosed hospitalized cases that have occurred up to that week). If you wonder how high it "should" go, based on the average of the last three flu seasons (October to April of each year) that level is the dashed horizontal line in each panel (NB: the scales are different for the top and bottom panels, because those are the age groups, the very young and the old, that usually have the highest risks so the curves wouldn't fit if the vertical scales of the other age groups was used). What this means for interpreting the curves is that if this year behaved like the average of the three previous years, the curve would slowly move upward until it reached the dashed line by the end of the flu season in April or May. Obviously this year is very different.

You once again see the altered age pattern, this time very dramatic when comparing the youngest age group with the oldest. For those of us in the over 65 age group, the seasonal has barely begun. We are just inching our way up from typical summer levels. There's a long way to go before we get to where we would usually be by the end of flu season. My age group looks pretty normal for this time of year. But if you look at the other panels you see that several have already exceeded, in the first week of the official flu season, the level of season risk we would have expected by the end of the season. Babies and toddlers are two thirds of the way there already (remember the scale is different for them so the same height is a higher risk than compared to the 2 to 4 year olds). The 2 to 4 year olds are already there and everyone between 5 and 49 years old has already exceeded their year end risk at a time when the season is usually just starting. The 50-44 year old group is already at seasonal average and then there's the over 65 age group, the exception that proves the rule: this is a pandemic strain.

Where and when it will peak we don't know but there's a long, long way until whatever causes flu to be seasonal is ended (usually sometime in April or May). Swine flu could burn itself out before then (but not before taking more children and adults with it); or it could keep going for the whole flu season; or it could co-circulate with the seasonal flu H1N1 and H3N2 strains. The assumption that swine flu will completely crowd out seasonal flu strains is premature and we could have a normal seasonal flu pattern in the over 65 age group appearing later. Or not. We still don't understand flu well enough to predict with any confidence what is going to happen.

The seasonal and swine flu vaccines are not intrinsically different except for the flu strains they contain. We change flu strains every couple of years routinely and these vaccines are made in the same way as we have been making them for many years. The only difference is a strain change, which is routine. This means that we have had extensive experience with the swine flu vaccine already, extending over years and hundreds of millions of delivered doses. It is not untested. Far from it.

The most rational thing to do at this moment, given what we know and don't know, is to get vaccinated with both seasonal flu and swine flu vaccines. That's what I'm going to do. I already got my seasonal flu shot and I'll wait in line for my turn for the swine flu vaccine and get it as soon as I can. You not only protect yourself but you help prevent spread of flu to others.

H1N1 Mortality Rates

A quick study about the virulence of H1N1 is out, and I wanted to share this, as well as a few other thoughts. First, understand the three main ways that the flu can kill you:

Influenza lethality is due to three main causes: First, direct viral origin, leading to viral pneumonia of high severity, with an acute respiratory distress syndrom (ARDS), associated with 30 to 50% lethality in intensive Care Unit (ICU) [1]; Second, bacterial surinfection, due to pneumococal, staphylococal, streptococal, or meningococal pneumonia, usely curable with appropriate antibiotics, provided they are administered early enough; and Third, decompensation of severe underlying conditions, often in elderly people or in vulnerable chronic patients.

What is of concern from the article is this passage:

New Caledonia and Mauritius figures are consistant to a rough estimate of about 1 death from ARDS due to H1N1pdm per 10,000 infections, i.e. a virulence of an order of magnitude of 100 times that observed for seasonal strains.

Now this is very important to understand. This is the ARDS related deaths, not the ones that are attributed to flu that strikes down people in numbers of about 30,000+ in the US each year. We probably will not see 3,000,000+ flu deaths in the US because of these numbers. First of all, as reported, the 30,000+ number is sketchy reporting in the media, and are not all ARDS related. Secondly, we actually do have a vaccine for this strain, and that should help a great deal.

HOWEVER, one of the things that this virus has shown is a greater effect on the young and healthy. Much like the 1918 flu pandemic. So those of you who say, "I never get sick." or "I have a strong immune system." or something along those lines, you may need to be extra careful this flu season. In layman terms, this virus can cause your immune system to go into overdrive, and afflict you with ARDS. Your strong immune system may be your biggest weakness and liability this year. Please take all the prcations that you can. If you feel ill, do not go out in public. Wash your hands often. Cover your nose and mouth when you cough and sneeze. AND GET VACCINATED! If not to save yourself, to save those around you. Who knows, you could end up saving the life of a loved one even.