Influenza Vaccine Overrated?

Study reignites vaccine, antiviral controversy

Debate to mandate the (flu) shot or not for healthcare workers in the United States continues as additional data suggests seasonal influenza vaccine may not be all its cracked up to be.

Canadian healthcare workers are getting two differing opinions on mandated flu vaccine according to a report published by Public Health Ontario/Canadian Medical Association. Some Canadian researches continue to endorse the mandated flu vaccine policy for healthcare workers citing an 86% effectiveness when the vaccine is well matched to circulating virus. Researchers also claim that flu vaccination of healthcare workers in long-term care facilities (LTCF) may decrease resident flu mortality by 5-20%. The Canadian report, published in CIDRAP, the Public Health Ontario editorial indicates that flu strains that may produce Guillian-Barre Syndrome (GBS) are avoided in vaccine production. Its not clear how, exactly, GBS causing strains of influenza are kept out of vaccine production.

In the United States many healthcare systems and some sates are mandating participation in a flu vaccination program, according to the Centers for Disease Control and Prevention (CDC). “Participation” may include mandated vaccine, vaccine or singing a declination form, or mandated to don a mask.

Adding to the vaccine mandate controversy is a report from the Center for Infectious Disease Research and Policy at the University of Minnesota. This report proposes that seasonal influenza vaccine offers little protection to otherwise healthy young and middle-age individuals. They also believe that the benefit may be even less for those greater than 65 years of age. The New York Times recently printed an editorial on this topic.

While the vaccine debate continues, use of the antiviral drug Tamiflu is drawing concern. You may recall that Tamiflu (oseltamivir), and a class of medications known as Neuraminidase (NA) inhibitors, has been used to treat influenza. These medications are also on the CDC list for the treatment of seasonal influenza. However, reports have suggested that influenza has become (or is becoming) resistant to Tamiflu. One report from the CDC (9 Jan 09) states early data from a limited number of states indicating that a high proportion of influenza A (H1N1) viruses are resistant to the influenza antiviral medication oseltamivir (Tamiflu®). An article in Medscape highlights Tamiflu concerns brought on by researchers in the British Medical Journal. If you'd like to read in scientific detail about Tamiflu resistance, check out this post from the Virology Blog.

What’s the answer?
We have to remember that season influenza A continues to change every year. Some years the vaccine is well matched to the circulating strain, while other years it may not be. Its important to have an understanding of the terminology, types and impact of influenza (see 3 things to know about seasonal flu MJ 11/10). You should also brush up on the non-pharmaceutical interventions of hand hygiene, respiratory etiquette, and (appropriate) social distancing.