Weekly H1N1 flu update

As an internist and primary care provider, I expect to be on the front lines during the upcoming flu season...whatever it may bring. Here's my first weekly flu report; stay tuned for future updates concerning the H1N1 vaccine, the latest in H1N1 research, and ways that you, your family, your friends, and co-workers can stay healthy through the fall and beyond!

A few words about seasonal flu

Influenza viruses are identified by their surface proteins that allow the little buggers to 1) stick to the cells of your throat and 2) thrive and multiply in your airway. H is for hemagluttinin, a protein that hooks the virus up to you, and N is for neuraminidase, a protein that promotes the release of newly made flu virus particles from the infected cell to its uninfected neighbors.

The reason that flu is such an ongoing nightmare is that the virus remakes itself every year with novel H and N proteins so that many people, even those who have previously had flu, aren't immune to the new variety. Every year we try to anticipate what this slippery little devil is going to do with respect to H's and N's and then develop a shot to promote immunity in all vaccinated persons. We particularly target those who are very young, very old, or otherwise affected with a chronic disease which would make them more susceptible to a complicated and dangerous case of the flu.

What's all the fuss about H1N1?

This past spring (late in the flu season) a new strain of flu emerged--first identified in Mexico--with novel H and N proteins. The strain was first traced to pigs--new influenza strains often start in pigs--thus the original name 'swine flu'. This name was dropped after pigs were unfairly targeted as the infectious source of the disease, but now we know of course that you cannot get H1N1 flu from eating pork.

The scary things about this new flu were that 1) it showed up in the Northern Hemisphere at a time when flu should be winding down, and 2) it appeared to be particularly severe or lethal in healthy, young adults, a group generally not at risk for flu complications or death. We are concerned, of course, that this H1N1 flu could cause another worldwide, devastating pandemic like the outbreak of 1918 which was also caused by an H1N1 type of influenza. Bird flu,incidentally, is typed as H5N1.

Lots of research is being done on this new strain, but the findings of flu expert Dr. Peter Palese and his team at Mount Sinai School of Medicine in New York are reassuring. They agree with CDC data that estimate only 10% of household contacts of patients with H1N1 will become infected which suggests that this bad actor is not as tough or transmissible as we originally feared.