A medical journal study published Wednesday found California's laws limiting vaccine exemption restrictions has increased the number of vaccinated kindergartners.

The number of unvaccinated students entering kindergarten decreased by nearly 5 percent between 2013 and 2017, after the state cracked down on restrictions, according to the study published in the Journal of Medical Association.

California lawmakers sought to modify exemptions after a 2013 measles outbreak.

California had seen an uptick from 7.8 percent of unvaccinated students in 2000 to 9.84 percent in 2013, according to the study.

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The state passed bills limiting "personal belief exemptions" and launched an educational campaign surrounding vaccinations.

The results are pertinent in 2019, as the Centers for Disease Control and Prevention is reporting its the country's worst measles outbreak in more than 25 years.

There have been 1,022 cases confirmed as of June 6 across 28 states.

The Sacramento Bee, which wrote about the study's results, reported California is looking to tighten the state's rules on vaccination even further.

Gov. Gavin Newsom Gavin NewsomOVERNIGHT ENERGY: California seeks to sell only electric cars by 2035 | EPA threatens to close New York City office after Trump threats to 'anarchist' cities | House energy package sparks criticism from left and right California seeks to sell only electric cars by 2035 EPA head questions connection of climate change to natural disasters MORE (D) is expected to sign a bill that would more strictly monitor doctors who approve a high number of exemptions, the paper reported.

New York Gov. Andrew Cuomo (D) signed legislation in June ending religious exemptions for vaccines, after the state saw unusually high numbers of measles cases.

New York City reported at least 588 cases of measles, and the New York Department of Health reported at least 336 confirmed cases elsewhere in the state.

Maine also recently voted to eliminate religious exemptions, but similar exemptions still reportedly exist in 46 states.