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As lifesaving as the COVID-19 vaccines have been, the measles vaccine has been an even greater success story. Before the vaccine was developed in 1963, outbreaks that occurred every two to three years were killing 2.6 million people worldwide a year, most of them children. Others developed pneumonia, or suffered brain injury and deafness from measles-associated encephalitis.

It's an incredibly contagious airborne disease. Put a person with measles in a room with 100 other people, and 90 of them will be infected. But the vaccine is even more effective than the disease is transmissible. If all 100 people in that room were vaccinated, only four would be infected.

So it's especially disheartening to observe the new measles cases in Florida — eight and growing at last count. It's not the biggest measles outbreak in recent years, but the ho-hum attitude of the state's top public health official, Surgeon General Joseph Ladapo, is deeply troubling.

Most of the cases so far have been among students at an elementary school in Broward County. But one is a preschooler — an extremely dangerous age for complications — whose connection to the school is unclear. Something like this was bound to happen. Measles is infectious from four days before the telltale rash appears to four days after. That means parents often don't know when their child might be infected and capable of transmitting the virus to others in and out of school.

Florida has a reasonable law requiring vaccination for children to attend private or public school. Unlike California, which allows exemptions only for children with legitimate health reasons, Florida lets parents opt out for religious beliefs, a common loophole throughout the country. And the vaccination rate at the elementary school in question was higher than the national average, at 97%.

The problem in quelling this outbreak, though, is the lackadaisical attitude of Ladapo, who has earned notoriety by promoting COVID-19 vaccine skepticism. Last month, he called for a halt to using mRNA vaccines to fight COVID-19. Still it was shocking that, in the midst of the outbreak, he ignored the public health standard set by the U.S. Centers for Disease Control and Prevention, which calls for isolating unvaccinated people for 21 days after possible exposure, and allowed parents to decide whether to send their unvaccinated kids to school. He didn't even encourage parents of unvaccinated children to get a quick, preventive dose.

It's a reprehensible endangerment of students at the affected school and the broader community, including babies too young to have been vaccinated. Children with compromised immune systems are at particular risk because they cannot safely be vaccinated. That includes children who are undergoing chemotherapy for cancer.

A vaccine effectiveness rate of 96% is superb, but it still means that about 4% of children don't get immunity from their shots. That's why public health officials rely on "herd immunity," meaning enough members of a community have been vaccinated to keep measles at bay.

The reason more unvaccinated children haven't been sickened in this country is because there are enough parents who do the right thing: vaccinate their kids and thus protect the other kids around them. But that may not be the case for long. Vaccine skeptics like Ladapo have been chipping away at Americans' confidence in vaccines in recent years.