The number of New Jersey children whose families are claiming religious exemptions from state regulations on required vaccinations jumped nearly 53% in the last five years, according to a new analysis from a major state hospital group.

The study by the Center for Health Analytics, Research and Transformation (CHART) at the New Jersey Hospital Association found that the percentage of children who claimed religious exemption rose to 2.6% in the 2018-19 school year from 1.7% in 2013-14.

That rise came amid a local and national resurgence of measles, an illness that until recently was considered wiped out in this country. The potentially fatal disease is also spreading globally, reflecting slipping vaccination rates. This week, the World Health Organization (WHO) said the United Kingdom, Albania, the Czech Republic, and Greece can no longer be considered countries where measles has been eradicated. Europe has already had about 90,000 measles cases this year, compared with 84,000 last year.

The group behind the new Garden State study says it hopes to draw attention to immunization and its health benefits.

“Our data study explored the rise in vaccine-preventable illness to better understand the factors that impact the health of the people of New Jersey,” said Sean Hopkins, senior vice president of CHART. “We respect the religious exemptions provided by the State of New Jersey. There remains, however, room for dialogue on the growing distrust of vaccine safety and the impact that it has on the health of our population.”

The vast majority of religions allow vaccinations. And major health organizations nationally and globally urge immunization. UNICEF estimates that vaccines save up to three million lives a year, and the WHO has hailed them as one of the greatest innovations in public health.

However, there has been a rise in vocal immunization opponents who believe vaccines pose health threats, and say parents are not adequately informed about potential risks. Most health experts say that the opponents’ fears aren’t backed by scientific evidence, and that depriving children of vaccines threatens their health and that of children who cannot be vaccinated because they are too young or due to other health problems.

Some opponents have expressed concern about the power of pharmaceutical companies to affect the information parents receive. Others insist that previous generations survived diseases like measles, and that immunity acquired “naturally” is better. Yet about 10% of measles cases this year have required hospitalization, according to the Centers for Disease Control and Prevention. And in the decade before the measles-mumps-rubella (MMR) vaccine was introduced in 1963, from 400 to 500 people died each year of measles.

Most parents get their children vaccinated. But people on both sides of the debate have increasingly — and passionately — turned to social media to share their views.

Even with the rise in exemptions in New Jersey, the state’s vaccination rate is still within the range that most experts consider to confer what’s known as “herd immunity,” meaning that enough people are vaccinated to stop a contagious disease from becoming widespread. The rate of vaccination needed to enable resistance to the spread of measles is often quoted as at least 90% to preferably 95%.

Yet New Jersey and Pennsylvania are part of the U.S. rise in measles cases. This year, through mid-August, there were 1,203 confirmed individual measles cases in 30 states. That includes 18 in New Jersey and 13 in Pennsylvania.

In all of 2018, there were 372 cases nationally, with 10% — or 37 — of them in New Jersey. The vast majority of those cases — 30 — were in Ocean County.

New Jersey allows exemptions for religious and medical reasons. In 2018-19, the state’s overall vaccination rate for schoolchildren was 94%. In the most recent period measured, medical exemptions amounted to 0.2% of children. A medical exemption can be sought for a child who has a condition that prevents vaccination or if a health professional attests vaccination could be detrimental to the child’s health.

The state Health Department “recognizes the importance of promoting vaccination across the lifespan, which is why we undertake educational and awareness campaigns to educate the public and providers how vital vaccines are in reducing these preventable diseases,” said spokesperson Dawn Thomas.

Among those efforts is the Vaccines for Children program, which provides vaccines for uninsured or underinsured youngsters, as well as incentive programs for child care centers, colleges and universities, and other institutions to encourage vaccination.

Pennsylvania allows schoolchildren to get vaccination exemptions on religious, medical and, unlike New Jersey, philosophical grounds, which can be sought if vaccination would violate the child’s or family’s personal or moral beliefs.

While the commonwealth had only two cases of measles in 2018, state health officials say there have been 13 so far this year. Pennsylvania was also one of the states that saw outbreaks of mumps, including more than 150 cases at Temple University.

Two years ago, the state instituted a more stringent vaccination policy in an effort to get more children immunized by the start of school. Unlike the old eight-month grace period for getting required vaccinations, the new rules allow children to be granted a waiver of only five days to get a mandated vaccine or risk not being allowed to attend school.

According to information from the Pennsylvania Department of Health, the exemption rates for children in 2017-18 were 1.7% philosophical, 1.3% religious, and 0.6% medical, up from 1.3% for philosophical exemptions, 1.0% religious, and 0.5% medical in 2015-2016.

In both states’ legislatures, bills have been proposed to limit vaccination exemptions.