It is most unfortunate to read the Andrew Wakefield episode, the physician being demonised for linking MMR vaccines with autism. In my opinion, he has erred on the side of caution, despite lack of appropriate scientific rigor, or accusations of fraud. A quick PubMed search shows that at least 500 articles relate vaccines with autism, with some suggesting that “U.S. male neonates vaccinated with the hepatitis B vaccine prior to 1999 (from vaccination record) had a threefold higher risk for parental report of autism diagnosis compared to boys not vaccinated as neonates during that same time period (Gallagher CM, Goodman MS.J Toxicol Environ Health A. 2010 Jan;73(24):1665-77). Other hypotheses suggest that the “combination measles-mumps-rubella vaccine causes autism by damaging the intestinal lining, which allows the entrance of encephalopathic proteins; (2) thimerosal, an ethylmercury-containing preservative in some vaccines, is toxic to the central nervous system; and (3) the simultaneous administration of multiple vaccines overwhelms or weakens the immune system” (Gerber JS, Offit PA..Clin Infect Dis. 2009 Feb 15;48(4):456-61.Vaccines and autism: a tale of shifting hypotheses)In Canada, researchers estimated the prevalence of pervasive developmental disorder with respect to MMR vaccination in 27,749 children from 55 schools in Quebec (Fombonne E, Zakarian R, Bennett A, Meng L, McLean- Heywood D. Pervasive developmental disorders in Montreal, Quebec, Canada: prevalence and links with immunizations. Pediatrics. 2006;118:e139-50).
Although 20 epidemiologic studies have shown that neither thimerosal nor MMR vaccine causes autism, it is not clear if the vaccine is entirely safe if used in the wrong way (any controlled studies?). And Dr.Wakefield’s publications might have only highlighted the pitfalls associated with abuse of MMR vaccines in particular and vaccines in general. He has erred but only on the side of caution given the myriad biotech and pharmaceutical products out there, not one of which is entirely safe and efficacious. After all, it is a question of risk-benefit analysis, and if in some cases the risk is overhyped or exaggerated, it should not be a cause for concern. It is something to be appreciated, instead, despite all the missed childhood vaccinations!
Competing interests: None declared
Source: BMJ Rapid Response, Medical Journalist Sridhar Nadamuni.
