After California enacted a policy to ban nonmedical vaccination exemptions for school-age children in 2016, the overall coverage for the measles, mumps and rubella vaccine increased by 3.3 percent, a study published in PLOS Medicine shows.
Researchers used publicly available state-level data from the CDC on MMR vaccination coverage, nonmedical exemption and medical exemption among children entering kindergarten in 45 states, including California, from 2011 to 2017. They also used county-level data on overall vaccine coverage and exemptions in 17 states from 2010 to 2017.
They found that at the state level, MMR vaccination coverage in California increased by 3.3 percent after the 2016 exemptions elimination policy was enacted, while nonmedical exemptions decreased by 2.4 percent and medical exemptions increased by 0.4 percent.
At the county level, overall MMR vaccination coverage increased by 4.3 percent, nonmedical exemptions decreased by 3.9 percent and medical exemptions increased by 2.4 percent after the implementation of the 2016 policy.