AMHERST — An analysis of policy research on nearly 50 years of school vaccine mandates has found that while vaccine requirements are commonly considered to have made a major, if not essential, contribution to vaccine coverage in the United States, the causal relations between mandates and population vaccination remains unclear.
The findings in the report, “Impact of school vaccination mandates on pediatric vaccination coverage: a systematic review,” were published by the Canadian Medical Association Journal’s CMAJ Open.
The team of researchers, led by Devon Greyson, assistant professor of communication at the University of Massachusetts Amherst, investigated the findings of 20 studies that looked at two forms of mandates, school-entry mandates (from 1970-2017) and adolescent, or “middle school,” mandates from the 1990s to 2015. Eighteen of the studies, including all of the adolescent mandate research, were set in the U.S., and two school-entry mandate studies were set in Italy and Australia, respectively.
They found that while adding well-accepted vaccines to an existing mandate is usually associated with increased vaccination, it is unclear to what extent such increases are due to the compulsory nature of the policies or to co-interventions that increase access and awareness.
“Vaccines are an important tool for keeping the community healthy,” Greyson said. “For most diseases, we need almost everyone to receive the vaccine in order to protect vulnerable community members such as babies and people with compromised immune systems. One approach to encouraging community vaccine coverage is to require that school children show proof of vaccination, with policies commonly called mandates.
“There are hints in the evidence that context and details matter a lot to how a vaccination mandate works out, though,” she cautions. “This means there’s not one universal answer to this question — what works in one place and time may backfire in another. There are theoretical risks to mandate policies, such as clustering of unvaccinated children, for example in private or home schooling, or in geographic areas where mandates don’t exist or aren’t enforced, which could lead to outbreaks even if exemptions are low and overall population coverage is high. Luckily, some newer studies are currently starting to investigate these important questions.”