2009 Pandemic H1N1 Influenza A: Where Do We Stand Now?

Extreme Thinkover Guest Article

By Dr. John Bogen, MD

Updated November 8, 2009

What is the current status of the pandemic in the U.S?

The CDC reported that for Week 43 (ended October 31, 2009), both hospitalizations and deaths from influenza dipped slightly. A total of 18 pediatric deaths were reported for the week. Virologic surveillance of 14,151 specimens sent to U.S. labs for testing revealed that 37.2% tested positive for influenza, a slight decrease. Of those that tested positive, 0.3% were influenza B, and 99.7% were influenza A. Of the influenza A strains subtyped, 99.9% were the pandemic strain, and only 0.1% were strains associated with strains seen in prior seasons. http://www.cdc.gov/flu/weekly/

What do these data mean for the average patient? The seasonal influenza vaccine has so far had little use, since almost all the influenza currently circulating is the new pandemic strain. The pandemic vaccine has just now begun to be distributed and given to patients. We are still in the heart of the flu season. It is too early to tell from the data if the country itself has “peaked” in terms of the number of cases. There are also regional and local differences – some areas have already been hit hard, as evidenced by school closures. Other areas have not yet peaked. It is also too early to tell if the pandemic vaccine has made any difference in the overall numbers.

In usual “non-pandemic” influenza seasons, an estimated 36,000 deaths occur directly or indirectly from influenza in the U.S., with 90% of these in the elderly or in those with weakened immune systems. One piece of good news this season is that the elderly population seems to have some immunity to the pandemic H1N1 strain, probably due to different H1N1 strains that were in circulation until the 1957 H2N2 pandemic, at which time H2N2 replaced H1N1 as the seasonal strain. So, we are seeing far fewer total deaths, just over 1,000 (but perhaps as high as 3,000, according to other CDC data not currently publicized) since the pandemic started.

The bad news is that we are seeing more than the usual number of deaths in younger people (under age 65). People with weakened immune systems are still dying disproportionately, and we are seeing more than the usual number of deaths in previously healthy individuals including children and pregnant women.

Data on vaccine safety are difficult to obtain at this time, since distribution of the vaccine has just begun. Several highly publicized anecdotes of serious reactions have appeared in the lay press. Most of these were with the seasonal vaccine. Ongoing clinical testing of the pandemic vaccine has continued to show good short-term safety. One must keep in mind that a temporal association between vaccine and symptom does not imply causality, but patients with serious reactions (e.g. anything more than local muscle soreness from the shot and the common few days of general malaise following the shot) can and should be reported to VAERS. It is quite obvious that, worst case scenario, that deaths from pandemic influenza greatly exceed the number of serious reactions from the vaccine.

The next few weeks will be critical.

Between vaccine being distributed / administered and the pandemic running its course through communities, one would hope to see a downward trend in hospitalizations and deaths. The vast majority of unvaccinated patients who get pandemic influenza will be fine after a few days of misery. Similarly, patients who get the vaccine prior to getting sick from pandemic influenza will not have a serious reaction to the vaccine and also will not get ill or die from the virus. If we see fewer deaths this season from influenza, that would be a good thing, but hardly a consolation to the families and friends of people who died from the pandemic.

If I may offer my educated opinion, I predict we will see fewer than 10,000 deaths in the U.S. this flu season.

The overall mortality rate will “only” be approximately 0.01% (1 in 10,000). The pandemic strain will continue to be the dominant strain of influenza in the community. Next year’s seasonal influenza vaccine will include the current pandemic H1N1 strain (or a mutated version thereof that exists next spring), and influenza B. With luck, subsequent seasons will be mild because so many would have already gotten ill and developed immunity to the novel H1N1. The elderly will continue to have some natural immunity, and the vaccine and herd immunity will protect most of the rest of the population.

H1N1 Flu Vaccine: The CDC Gets it Right

You and I, right now, are living in the middle of a pandemic.   It’s in the news, but unless you are paying close attention above the noise coming out of Washington, D.C. on the East Coast, the media frenzy over Michael Jackson’s death on the West, or you folks in the middle of the country dodging humongous thunder storms, it may not be much on your personal radar.

But it should be.  Not at a Hollywood plague & panic mode, by any means, but H1N1 is a nasty virus.  As a chaplain, I have worked with several patients and their families who are being treated for H1N1.  Two were in our intensive care unit.  Both of these patients had developed pneumonia, and one was a pregnant woman (who had to be delivered early to save both her life and the baby’s).

In my 13 years as a chaplain, and having seen hundreds of cases of pneumonia, I was astonished–and I truly mean astonished–at how sick those two patients were (they both continue to recover. The infant did not have the virus.).   I can also say, that our patients generally match the age distribution and other physical conditions of those the Centers for Disease Control say are most at risk.

So, what’s a body to do?  First, go to http://www.flu.gov and check out the most current recommendations.  What prompted this post was this week’s announcemnt by the CDC of the priority list for who should get the vaccine when it becomes available.  Here is the list:

On July 29, 2009, the Advisory Committee on Immunization Practices (ACIP)—an advisory committee to CDC—recommended that novel H1N1 flu vaccine be made available first to the following five groups (News Release):

Pregnant women

Health care workers and emergency medical responders

People caring for infants under 6 months of age

Children and young adults from 6 months to 24 years

People aged 25 to 64 years with underlying medical conditions (e.g. asthma, diabetes)

Combined, these groups would equal approximately 159 million individuals.

You’ll see this is not the typical order for vaccination priorities, which is the elderly, people with certain other conditions that make them more susceptible, etc.  The reason for the change is very straightforward:  H1N1 infects a different set of demographics than the usual winter time influenzas.

This is where you need to pay attention.  H1N1 has idiosyncrises that we are not used to.   And the way it is spreading is one of those.  The CDC has provided a map so you can look at where the flu is having the most impact:

US Map H1N1 Flu Distribution 31Jul09.  Source: CDC

US Map H1N1 Flu Distribution 31Jul09. Source: CDC

Here is how to recognize possible H1N1 symptoms, from the CDC’s Website:

Emergency Warning Signs

If you become ill and experience any of the following warning signs, seek emergency medical care.

In children, emergency warning signs that need urgent medical attention include:

* Fast breathing or trouble breathing

* Bluish or gray skin color

* Not drinking enough fluids

* Severe or persistent vomiting

* Not waking up or not interacting

* Being so irritable that the child does not want to be held

* Flu-like symptoms improve but then return with fever and worse cough

In adults, emergency warning signs that need urgent medical attention include:

* Difficulty breathing or shortness of breath

* Pain or pressure in the chest or abdomen

* Sudden dizziness

* Confusion

* Severe or persistent vomiting

* Flu-like symptoms improve but then return with fever and worse cough

Protect Yourself, Your Family, and Community

* Stay informed. Health officials will provide additional information as it becomes available. Visit the CDC H1N1 Flu website.

* Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.

* Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hand cleaners are also effective.

* Avoid touching your eyes, nose and mouth. Germs spread this way.

* Try to avoid close contact with sick people.

* If you are sick with a flu-like illness, stay home for 7 days after your symptoms begin or until you have been symptom-free for 24 hours, whichever is longer, except to seek medical care or for other necessities. Keep away from other household members as much as possible. This is to keep you from infecting others and spreading the virus further.

* If you are sick and sharing a common space with other household members in your home, wear a facemask, if available and tolerable, to help prevent spreading the virus to others. For more information, see the Interim Recommendations for Facemask and Respirator Use.

* Learn more about how to take care of someone who is ill in “Taking Care of a Sick Person in Your Home”

* Follow public health advice regarding school closures, avoiding crowds, and other social distancing measures.

* If you don’t have one yet, consider developing a family emergency plan as a precaution. This should include storing a supply of extra food, medicines, and other essential supplies. Further information can be found in the “Flu Planning ChecklistExternal Web Site Policy.

Related Media: YouTube: Symptoms of H1N1 (Swine Flu)

http://www.youtube.com/watch?v=0wK1127fHQ4&feature=channel_page

(Sorry, I couldn’t seem to get this video to embed.  Just click on the link to view it.)

The take home on this is simple: if you are in one of the groups designated as high risk for H1N1, get vaccinated as soon as possible when the shots become available.  If you aren’t in those first groups, don’t get your dander up.  The people who are in the high risk categories really are in danger of getting critically ill if they contract H1N1.  There will be vaccine available for you, too.

But keep in mind, even if you fall into the usual categories a for seasonal flu shot, the H1N2 vaccine will not replace your yearly dose.  For most of us, we’re going to be getting poked twice, just not all at the same time.

One last thing.  Go wash your hands.

Wash 'em Hand Washing Image: CDC

Wash 'em Hand Washing Image: CDC