Long Island's positivity rate for coronavirus topped 1% Tuesday, the highest since May.

One doctor says the positivity rate may be rising because people are socializing both outdoors and indoors at larger gatherings, like graduation parties and weddings -- events where people may be eating, without a mask, and not social distancing without knowing everyone's vaccine status.

Dr. Sharon Nachman, chief of Pediatric Infectious Disease at Stony Brook Hospital, says she is very concerned about the rising number of people testing positive for coronavirus on Long Island.

"The delta variant is so highly contagious, and people have taken in the message of, 'You don't need to wear masks outside.' They're not wearing masks indoors, they are getting infected, perhaps because they have not been vaccinated and that's causing spread within our communities," Dr. Nachman said.

Nassau County Executive Laura Curran says since the county is not doing the same amount of testing, like for events and school sports, the numbers reflect the smaller pool of people being tested.

"The percentage is higher, but it's a smaller pool of people who are getting tested," Curran said.

Dr. Nachman says most of the positive cases that result in people getting sick with severe symptoms or being hospitalized are in people who are unvaccinated.

Her advice for what people should do to drive the numbers back down is to wear a mask in public places, and to reconsider getting a vaccine if unvaccinated.