- Carrat et al, Epidemiology and Infection 2006 (France): “…long-term consequences of repeated influenza vaccination are unknown.”
- Ohmit, et al; Clin. Infect Dis., 2013 (University of Michigan): getting flu shot 2 years in a row may lower protection.
- Nayak, et al; Journal of Immunology, 2013 (University of Rochester): “unexpected deleterious consequences” of “periodic natural infections with influenza and the yearly administration of inactivated influenza vaccines containing internal virion proteins.”
- Janjua, et al; Clin Infect Dis., 2010 (British Colombia Centers for Disease Control): “unexpected association between receipt of TIV and pH1N1 illness.” These observations led to 5 additional studies through the summer 2009 in Canada, each of which corroborated their initial findings.
- As early as 1999, Variable efficacy of repeated annual influenza vaccination had been modeled. (Smith, et al; Proc Natl Acad Sci U S A, 1999).
- In 2014, data were presented from a CDC study that analyzed vaccine efficacy over years of repeated vaccination. Using 5 years of historical vaccination data, the researchers reported that their data “suggested a significant difference in current-season VE among frequent vaccinees compared with nonvaccinees.” (McLean, CID 2014).
RELATED NEWS REPORTS:
- 1/18/2015 CBC News Flu vaccine paradox adds to public health debate: “Canadian problem” an example of odd effects of prior vaccination.