By Louisa Moller

BOSTON (CBS) — Among the bucolic lighthouses and rolling bluffs, there’s something fishy happening on Martha’s Vineyard. Just days before Massachusetts dropped all COVID-19 restrictions, the island reported a small coronavirus surge of sorts that started earlier in the spring.

“Week ending April 3rd, we had the most cases we’ve had since the beginning of the pandemic,” said Maura Valley, the health agent for Tisbury.

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According to the state’s COVID-19 dashboard released on May 27, Dukes and Nantucket counties were the only counties that reported COVID positivity rates higher than the previous two weeks at 5.28%. That rate is more than five times higher than the state’s average of 1.03%.

“It seems to be younger people but that’s probably because a larger number of them are not vaccinated,” Valley said.

The trend is puzzling as Dukes County has a high percentage of residents fully vaccinated, 68% according to state data.

(WBZ-TV Graphic)

Dr. Michael Stoto, an epidemiologist and public health researcher at Georgetown University and the Harvard T. Chan School of Public Health, said the Vineyard may simply be detecting more cases of the virus than regions where COVID testing has waned.

“And the reason is because there’s been a very effective testing infrastructure and contact tracing infrastructure,” said Stoto, who is also a Vineyard summer resident.

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What the data demonstrates is that the virus can continue to exist even among small pockets of unvaccinated people. The same holds true in Hampden County which has the lowest number of fully vaccinated residents in the state at 37%. There, the COVID-19 positivity rate is 2.19%, a number lower than the previous two weeks.

The numbers are similar in Bristol County, where the percentage of the population fully vaccinated stands at 41%. The COVID-19 positivity rate is 2.39% and falling.

Dr. Dani Hackner, the physician in chief for Southcoast Health, said he believes demographics have something to do with Bristol’s low vaccination rate.

“You think that folks who have chronic illnesses and social vulnerability would be more likely to get vaccinated but that’s not always the case,” he said.

Even as numbers drop, Hackner said unvaccinated individuals continue to get the virus and face hospitalization.

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“We have seen some very sad cases of people who did not want to get vaccinated and it led to very severe illness.”

Louisa Moller