ROCHESTER, N.Y. — Summer is nearing its end, and illnesses are top of mind as kids prepare to go back to school. Upstate New York has seen an uptick in measles cases, growing to more than 20 confirmed cases in a matter of weeks.

“The reason we’re so concerned about measles, as is the state health department, as is the CDC and federal folks, is that it’s very highly contagious. It’s one of the most contagious illnesses that we deal with in public health,” said Seneca County Public Health Director Scott King. “To put that into layman’s terms, if a contagious person is in a room with other unvaccinated individuals, there’s about a 90% chance that those unvaccinated individuals are going to catch measles then and walk out the door with that illness. That’s how contagious it is.”

Seneca County has three lab-confirmed cases of measles, and King says they’re anticipating two additional lab results to add to that list. King explains symptoms can look many ways, from cold or flu symptoms, fever or red and watery eyes, and a distinct rash that begins on someone’s hairline. He says symptoms could start four days before they show.

“You could develop measles and as far out as 21 days following an exposure. That’s a very long time,” King said. “Let’s also take into account that we know there are many more cases behind those official cases, because for every person who has measles and is infectious, if they’re interacting with other unvaccinated individuals, the science tells us the epidemiology tells us that those contagious individuals will infect an average of 12 to 18 others.”

Seneca County is similar to several others across upstate dealing with measles exposures. Allegheny County has confirmed at least four cases, but Supervising Public Health Educator Rob Matasich says there are more than a dozen other presumed positive cases. Matasich says the county has vaccinated 131 individuals for measles since the beginning of the month.

“They were primarily coming to us as word spread. You know, we would get a phone call and then … I believe actually, most of these were administered when our nursing staff would go out and provide the vaccines on site. And that way, we’re not … bearing the risk of exposing other individuals by having them travel,” Matasich said.

“Vaccination is the single best way to prevent getting measles. A single dose of the vaccine imparts immunity to about 90% of people who get that first dose. And then, to be fully vaccinated, you get a second dose that gives immunity to about 97% of people,” King added.

New York State Health Commissioner Dr. James McDonald agrees that vaccines are the best form of preventing the spread of the measles virus. He recalls an outbreak of measles in New York years ago that he says vaccines have prevented a recurrence of.

“We had the outbreak in New York City in 2018, 2019. That was well over 600 cases. But I think what you’re seeing is we’re seeing an increase in New York State. What I want to do is make sure people know there is a way to prevent this, and that’s to make sure you’re up to date on your measles, mumps and rubella vaccine,” McDonald said.

“We’re not here to force vaccination on anyone. We’re here to give them the information to empower them so that hopefully they can make decisions that are best for them and hope that those decisions will have benefit to the wider community. More folks that get vaccinated, the better off we all are,” King added.

Health officials say that most people who were born before 1957 are likely to have natural immunity since they probably had measles before. While health officials all agreed that vaccination is the best form of prevention, they understood the method doesn’t work perfectly the same on every individual. Someone who’s immunocompromised, going through chemotherapy, is pregnant, or children younger than 2 who have not had the chance to be vaccinated are all at higher risk.

New York does have requirements for the measles vaccination for children going to public school.