The Novel H1N1 Vaccine

"Swine flu" or the novel H1N1 influenza this year has created an interesting mix of reactions. Since the first outbreak in March/April of this year to the declaration of a pandemic in June to the development of a vaccine, some have become terrified of this disease and others have become terrified of the vaccine. Should we vaccinate? Is the lack of widespread equitable distribution of the vaccine a failure on the part of the government?

The vaccine is created similarly to seasonal influenza vaccine, and side effects are expected to be similar. Several trials looking at dosing of vaccine and antibody titer response have shown that getting the vaccine effectively induces an immune response against those antigens. The hope is that this will prevent transmission of the influenza virus from an infected host to an immunized individual.

However, we don't have any data that this works. The theory is sound, but there are no studies on whether the H1N1 vaccine prevents infection. Indeed, it'd be hard to design a study; you'd have to randomize people to getting vaccine and placebo and see if they make it through the flu season without getting sick. So do you believe in evidence based medicine? If you do, you have to concede that all this hullabaloo over vaccination can't really be supported by numbers. We think it works, but we simply don't know.

I fully support getting the H1N1 vaccine; I believe in the biology and immunology, and I think it works. But not having numbers bothers me. What if the vaccine isn't all that good and only prevents 10% of infections? Are we spending our money wisely? Are we rationally weighing risks and benefits? That being said, there is a study modeling the cost-effectiveness of vaccination that suggests that vaccinating 40% of a large U.S. city with a 75% effective vaccine would avert 1468 deaths and save $302 million. This would require 3.3 million vaccine doses (if one dose is effective for an adult). I'm always iffy about modeling studies, but that's the best evidence we have so far.