The public’s concern about adverse events, especially death, immediately or soon after vaccinations is very disruptive to vaccine uptake, leading to increased morbidity and mortality of vaccine-preventable diseases. For example, a 2009 Japanese study that showed 107 deaths following H1N1 influenza A vaccination, assumed a causality between the vaccine and the deaths without any evaluation of background rates of of deaths, which would help indicate whether there was any significance to the death rate or even if its related to the vaccination. Vaccine mortality is one of the most abused terms in discussions about vaccines.
It has been demonstrated that passively reported data, that is, data that isn’t actively investigated by trained researchers, cannot be used to assess causality. In an active investigation, it was found that only 2 of the 107 deaths had an autopsy performed, and most of the others had other underlying diseases and conditions that were causally related to the mortality events. Furthermore, 15 million people were vaccinated with the H1N1 seasonal vaccine, and it would be expected that there would be >8000 deaths during the 20 days after vaccination using a crude mortality rate in Japan. Though it would still be a misuse of statistics, there really is more evidence that the H1N1 vaccination lowered the background death rate from 8000 to 107 post vaccination. Continue reading “Properly evaluating vaccine mortality – let’s not abuse VAERS”