Thursday, 9 July 2015

Vaccine safety in the face of narcolepsy

Last week in Science Translational Medicine their was an interesting article that showed how the H1N1 vaccine Pandemrix manufactured by GlaxoSmithKline in 2009 may have caused narcolepsy in some people that received the vaccine. The reason that this is believed to have happened is due to some people being susceptible to an auto-immune response (when you immune system attacks your own body) which got triggered by the vaccine. This trigger in the vaccine was caused by the inclusion of a nucleoprotein in the vaccine. I should point out that the researchers do say they need a larger data set to confirm this finding, however I think they are probably on the right track with their analysis due to other findings discussed below.

Now while this side-effect is certainly very sad, it is important to realize that the data still shows the extreme safety of vaccines in general. Of the 30 million people in Europe that received the vaccine, only 1300 people developed narcolepsy. This is a side effect ratio of 0.003 % which is not bad for a medical preventative when you consider the side effects that are associated with simple drugs like Ibuprofen that get used everyday. Additionally, this means that researchers have garnered important information to make vaccines even safer. This was a perchance discovery as the vaccine Focetria produced by Novartis, which was also produced to fight H1N1 in 2009, did not have this side effect as it did not include the nucleoprotein which caused this auto-immune response. Additionally, the
Arepanrix vaccine developed by GlaxoSmithKline as a H1N1 vaccine included less nucleoprotein and had a much smaller chance of a narcoleptic side effect.

So there you have it, just more evidence that vaccines are safe even in the face of a very serious side effect. What happened was sad, but it is no reason to not protect yourself after all the effect of getting the flu virus is a death rate which can be as high as 5% when pneumonia is included in the mortality rate.