Stay armed against influenza

Every year we fight new battles against influenza, an old yet rejuvenated virus. Antigenic variations, deviation from vaccine composition and antiviral resistance spice up our coexistence and force us to keep abreast. I propose you follow three quick steps before you enjoy some hot chocolate and a good movie in this cold winter.

1. Know your enemy

Thank you flu, for being smart and keeping us occupied. How do you know if influenza virus is picking up? First, check within your own local community: your hospital, your regional virology laboratory and your colleagues. Second, monitor the weekly flu surveillance website at the CDC. The first two columns of the surveillance table on their website indicate activity per region. Although it may lag some days behind your local sources, it should be good for your needs.

2. Know how to fight it

Schematically, we have two groups of viruses and two main groups of antivirals. In addition, you need to know two things:
a) Adamantanes (amantadine, rimantadine), that inhibit the M2 ion channel protein, work only against influenza A.
b) Neuraminidase inhibitors (oseltamivir, zanamivir) that inhibit the neuraminidase protein are in theory active against both influenza groups A and B.

BUT

The tested flu A strains H1N1 so far are RESISTANT to oseltamivir. This was noted one year ago in Norway. A nice editorial to a related study can be found in the February 15 issue of Clinical Infectious Diseases.

The tested flu A strains H3N2 so far are RESISTANT to adamantanes.

All flu B strains are SUSCEPTIBLE to neuraminidase inhibitors.

Find the right doses here! You are welcome.

Remember that zanamivir, which is delivered by inhalation, is licensed only for use in children without underlying respiratory or cardiac disease.

3. Prevent it. Heard that before?!

Why are only 40% of health care workers immunized?? What’s wrong with you people?!

I’m sick of hearing individuals involved in patient care complaining about side effects (selfish), futility ("the vaccine doesn’t work"), ignorance, irrelevance ("I can deal with the flu by myself"), or laziness ("too far away to get the shot"). First, do no harm. If you are in this list, you are vaccine deficient until proven otherwise.

Children aged 6 months to 18 years need this vaccine; children younger than age 8 may need two doses.

On Aug. 5, 2008, the FDA approved the following vaccine composition for the 2008-2009 influenza season in the United States:

an A/Brisbane/59/2007 (H1N1)-like virus;

an A/Brisbane/10/2007 (H3N2)-like virus; and

a B/Florida/4/2006-like virus.

The A/Brisbane/10/2007 is a current southern hemisphere vaccine virus. B/Florida/4/2006 and B/Brisbane/3/2007 (a B/Florida/4/2006-like virus) are current southern hemisphere vaccine viruses. It may be a little early to say confidently how the vaccine matched with the circulating strains.

I hope these short reminders are helpful. By the way, I received the vaccine. It is never too late!