A couple of weeks ago the autism-hating, anti-vaccine blog Age of Autism ran a story of vaccines killing and hospitalising several infants in Chiapas, Mexico during a routine immunisation programme. As of this writing only one commenter linked to a news story of possible bacterial contamination and the author of the blog post hasn't even bothered to issue a correction.
However, Orac in his usual Respectful Insolence style correctly urged patience for the investigation to conclude and that bacterial contamination was a more likely explanation. Well that investigation has concluded and it was a bacterial source but not from the vaccines themselves but rather externally during handling and administration:
- Although no hypothesis is not rejected, the only vaccine given in common to all children affected was that of Hepatitis B, so the research focused on the biological.
- The batch of the vaccine was properly certified.
- No adverse events were recorded after 100,000 doses were administered in various parts of the country since Oct. 2014.
- Results of blood cultures at that time showed the presence of the local external contamination, outside the biological vaccine, in particular bacteria, which was consistent with the clinical pictures of hospitalized children. Microbiology studies conducted on children reported the finding of Staphylococcus hominis, a type of bacterium commonly found in the skin of people. These findings rule out other bacteria, such as those found in the gastrointestinal tract and airways. Molecular studies demonstrated that isolated Staphylococcus hominis in different patients was the same, namely that the bacteria came from a single source of contamination.
- In conclusion, the Federal Commission for Protection Against Health Risks (COFEPRIS) analysis found that the vaccine was not defective and remained in temperature. Therefore, bacterial contamination occurred during the procedure of handling and application of the vaccine.