Vaccine Safety Studies

Recent outbreaks of influenza, varicella, pneumococcal disease, measles, and pertussis have all been found to be associated with vaccine refusal [1]. A vast majority of parents of young children are concerned about vaccine safety [1]. However, vaccine safety studies are frequently being conducted and published, and the conclusion is always the same: Vaccines are a safe and effective way to prevent serious disease.

Below are highlights from recent vaccine safety studies:

  • Researchers from the Centers for Disease Control and Prevention (CDC) found no adverse risks associated with the 1.16 million flu vaccines administered in the United States during the 2010-2011 flu season [2].
  • In a case-control study of 1,000 children, researchers found no association between “too many vaccines too soon” and autism [3].
  • In a longitudinal study that followed 1,000 children over 10 years, researchers found no benefit in delaying vaccinations during the first year of life. In fact, children who received timely vaccinations were found to have better developmental outcomes [4].
  • In a cohort study of over 700,000 children who received measles vaccinations, researchers found no statistically significant risk of seizures [5].
  • In a retrospective study of nearly 500,000 children, researchers found no difference in rates of autism between children who were vaccinated with a thiomersal-containing vaccine and children who received a thiomersal-free vaccine. (Thiomersal is a preservative in vaccines to prevent serious adverse effects, such as the Staphylococcus infection.) [6]
  • In a surveillance study of more than 200,000 vaccine recipients, there was no evidence of increased health risks [7].


Works Cited

[1] Atwell JE et al. (2014). Pertussis resurgence and vaccine uptake: Implications for reducing vaccine hesitancy. Pediatrics, 134(3): 602-604.

[2] McCarthy NL et al. (2013). Evaluating the safety of influenza vaccine using a claims-based health system. Vaccine, 31(50): 5975-5982.

[3] DeStefano F et al. (2013). Increasing exposure to antibody-stimulating proteins and polysaccharides in vaccines is not associated with risk of autism. The Journal of Pediatrics, 163(2): 561-567.

[4] Smith MJ et al. (2010). On-time vaccine receipt in the first year does not adversely affect neuropsychological outcomes. Pediatrics, 125(6), 1134-1141.

[5] Klein NP et al. (2012). Measles-containing vaccines and febrile seizures in children age 4 to 6 years. Pediatrics, 129(5): 809-814.

[6] Peltola H et al. (1998). No evidence for measles, mumps, and rubella vaccine-associated inflammatory bowel disease or autism in a 14-year prospective study. The Lancet, 351(9112): 1327-1328.

[7] Daley MF et al. (2014). Safety of diphtheria, tetanus, acellular pertussis and inactivated poliovirus (DTaP–IPV) vaccine. Vaccine, 32(25): 3019-3024.