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Tuesday, July 1, 2014

Vaccine Safety

Margaret A. Maglione and colleagues have an article in Pediatrics titled "Safety of Vaccines Used for Routine Immunization of US Children: A Systematic Review."

The abstract [links and emphasis added]:
BACKGROUND: Concerns about vaccine safety have led some parents to decline recommended vaccination of their children, leading to the resurgence of diseases. Reassurance of vaccine safety remains critical for population health. This study systematically reviewed the literature on the safety of routine vaccines recommended for children in the United States.

METHODS: Data sources included PubMed, Advisory Committee on Immunization Practices statements, package inserts, existing reviews, manufacturer information packets, and the 2011 Institute of Medicine consensus report on vaccine safety. We augmented the Institute of Medicine report with more recent studies and increased the scope to include more vaccines. Only studies that used active surveillance and had a control mechanism were included. Formulations not used in the United States were excluded. Adverse events and patient and vaccine characteristics were abstracted. Adverse event collection and reporting was evaluated by using the McHarm scale. We were unable to pool results. Strength of evidence was rated as high, moderate, low, or insufficient.

RESULTS: Of 20 478 titles identified, 67 were included. Strength of evidence was high for measles/mumps/rubella (MMR) vaccine and febrile seizures; the varicella vaccine was associated with complications in immunodeficient individuals. There is strong evidence that MMR vaccine is not associated with autism. There is moderate evidence that rotavirus vaccines are associated with intussusception. Limitations of the study include that the majority of studies did not investigate or identify risk factors for AEs; and the severity of AEs was inconsistently reported.

CONCLUSIONS: We found evidence that some vaccines are associated with serious AEs; however, these events are extremely rare and must be weighed against the protective benefits that vaccines provide.
In the same issue, Carrie Byington writes:
The relationship between parents of young children and their medical providers is powerful. Parents trust their child’s doctor over government officials, family members, or celebrities as the best source of information on vaccine safety.16,17 Furthermore, there is concordance between the beliefs of parents and the beliefs of their child’s health provider about vaccine  safety.18  Importantly, data also demonstrate that for parents who are hesitant to immunize their children but who ultimately do so, it is the physician’s recommendation that is most often cited as the reason they chose to vaccinate. Clinicians can examine the nonbiased data presented in the IOM report and the report by Maglione et al to increase their own confidence in vaccine safety and their advocacy for vaccines. Ideally, provider confidence in vaccine safety will increase the confidence of the families they serve and increase vaccination rates for children, safeguarding the health of the nation.
16. Freed GL, Clark SJ, Butchart AT, Singer DC, Davis MM. Sources and perceived credibility of vaccine-safety information for parents. Pediatrics. 2011;127(suppl 1):S107–S112
17. McCauley MM, Kennedy A, Basket M, Sheedy K. Exploring the choice to refuse or delay vaccines: a national survey of parents of 6-through 23-month-olds. Acad Pediatr. 2012; 12(5):375–383
18. Mergler MJ, Omer SB, Pan WK, et al. Association of vaccine-related attitudes and beliefs between parents and health care providers. Vaccine. 2013;31(41):4591–4595