Researchers have apologized to the Pennsylvania Department of Health for erroneously calling Pittsburgh a “hot spot” for kids going unvaccinated for religious or philosophical reasons.

In the PLOS Medicine article, authors define hot spot as a large metropolitan area where more than 400 kindergarten-aged children have opted out of receiving vaccinations for non-medical reasons. The article initially reported that there were 424 of these students in the Pittsburgh area during the 2015-16 school year, but Allegheny County data show the number is only 236.

Two of the authors sent the apology on Friday, three days after the article was released. Baylor College of Medicine vaccine expert Peter Hotez and Melissa Nolan, an epidemiologist at the University of South Carolina, said they are requesting the journal to publish corrections.

"We are informing the appropriate media sources," said Hotez and Nolan in their apology. "We wholeheartedly apologize to you, the Pennsylvania Department of Health, and the residents of your state for this oversight."

Hotez explained the mistake was due to a calculation error, but even with the corrections, he said some northeastern Pennsylvania counties aren't doing great.

"Going from Potter to Susquehanna County to Wayne County," said Hotez. "In some cases it looks like as many as 4 percent, 5 percent [of kids aren't being vaccinated for non-medical reasons.]"

Allegheny County, in contrast, reported that only 2.1 percent of kids fell into this category for the 2017-18 school year.

In a statement, the county health department said, "Over the last four years, the Health Department saw no significant increase in the rate of non-medical exemptions to vaccination in Allegheny County in kindergarteners."