What can we expect? 

We know that H1N1 flu is quite contagious, easily passed person to person via contaminated secretions from coughs and sneezes, and able to survive on surfaces for up to 8 hours.  While the initial reports from Mexico were quite disturbing with respect to the severity of illness caused by this strain, the illness lately has been acting a lot like seasonal flu. It does disproportionately affect persons under 60 and and can be unusually virulent in those under 25. Per Dr. Jay Butler of the CDC,  "75% of the [H1N1]hospitalizations are in those aged under 49 and 60% of the deaths are in those under age 49." Studies showed that no young adults demonstrated circulating antibodies to H1N1 prior to this pandemic whereas at least 1/3 of older adults apparently encountered a similar influenza variety in the past as they were found to have some immunity to this strain. 

Experts are unable to estimate the community prevalence of H1N1 because many cases are too mild to come to medical attention.  In addition, as H1N1 becomes more prevalent, the CDC no longer recommends that such mild cases be tested to confirm the presence of this specific virus. 

I've mentioned in previously mailings that influenza is a tricky and changeable foe which can mutate rapidly.  Thus far, thankfully, studies of the virus from recent cases in the southern hemisphere demonstrate no significant genetic change from northern cases investigated earlier this year. 

What's the difference between H1N1 and the seasonal flu? 

H1N1 is a novel strain originating in swine (but not caused by consumption of pork!) that developed in North American pigs through the mixing in their respiratory tracts of genetic material from swine, human, and avian flus.  It is antigenically distinct from seasonal flu which means that its proteins and genetic material are completely different than the ordinary influenza types that circulate each winter season. 

Will I need shots for both? 

Absolutely.  Separate shots will be available for seasonal and H1N1 flu.  We do not yet know whether one or two vaccinations for H1N1 will be necessary, so you may need either two or three shots total this year for flu protection.   

The seasonal flu shot and the H1N1 shot can be taken on the same day--but different arms please!  The seasonal shot is already available, however, whereas the first H1N1 vaccines will not be distributed until late October.  While the optimal time to receive the seasonal flu shot is October or November to assure that immunity lasts through the entire season, the CDC currently recommends that persons receive the seasonal vaccine as soon as possible to assure that both flu shots can be administered to the largest number of people. 

How can I get the H1N1 vaccine? 

While the CDC was hopeful that ample vaccine would be available by October, production delays will slow delivery of adequate vaccine until later on in the year.  For this reason, certain groups have been assigned top priority for the first wave of vaccinations, chosen due to their risk for more serious disease.  These include:

• Pregnant women
• Persons who live with or provide care for infants aged <6 months
• Health-care and emergency medical services personnel with direct patient contact
• Children aged 6 months--4 years, and
• Children and teens aged 5--18 years who have high risk medical condition