just in case...

I have been told I have seemed anti-vaccine as I have blogged about the mandatory H1N1 and flu vaccines for health care workers (HCWs). I did pause over the notion that something like this could be mandatory for half a million people, many of whom explicitly stated they did not want it, for me the central issue was not rights, but efficacy. To me, if the two vaccines had been proven to be very effective in preventing transmission of the flu, it would be justified to require health care workers to get them. Similar logic has been applied to the MMR vaccine, which is mandatory for NYS HCWs, despite challenges in court. However, if the efficacy was low or even not well established, I thought requiring it would be wrong

The logic of the mandate was that HCWs who got the vaccine would be less likely to transmit flu to their patients than non-vaccinated HCWs because their immune systems would be better equipped to fight off the infection. I was unable to find any studies addressing this point explicitly. However, I did find an article in the September issue of the New England Journal of Medicine addressing the overall effectiveness of the flu vaccine. The article was especially interesting because the objection I have head most to the flu is, "how well does it work in young, healthy people?", and participants in this study were all between 18 and 49 years of age. In fact, the mean age of participants was 23.3 with a standard deviation of 7.4 years. That said, no one was excluded from the study on the basis of health unless they had a condition for which the flu vaccine was contraindicated.

The study's intention was to compare the efficacy of the inactivated virus vaccine to the live virus vaccine. The 1952 subjects, all eligible to receive either vaccine, were randomized into two groups. Within these groups, 5 out of every six people received a vaccine, the sixth received a placebo. INTERESTINGLY, each of the vaccines contained three strains of flu, two type As and one type B. One of the type As was H1N1. Subjects were told to follow up if they had a respiratory symptom (stuffy nose, cough) combined with a "constitutional symptom" (fever, malaise). If and when they did, the organism infecting them was cultured.

In the end, 119 participants came down with the flu. One had H1N1, and the others were infected with either the other A strain contained in the vaccine, H3N2, or a B strain that was not in the vaccine. The efficacy of the vaccine with inactive virus when compared to the efficacy of placebo was 73%, the efficacy of the active virus compared to placebo was 51%. Obviously, the inactive vaccine was the more effective of the two.

So there you have it. If you get the inactive flu vaccine, even if you're young and probably healthy, there's a significantly smaller chance you'll get the flu than if you don't. To what extent this translates to a diminished likelihood of transmitting it to someone else is still unclear, although the inference that it would lead to a significantly diminished transmissions is more plausible in light of this rate of efficacy. Frankly, the results were more dramatic than I anticipated, and while I'm still not sure I agree with mandating the flu shot, I am more sympathetic to the idea than I was before seeing these results.