ALBANY COUNTY — Well over a third of the county residents infected with COVID-19 between Aug. 2 and 6 were vaccinated against the virus.

On Tuesday, Albany County Executive Daniel McCoy released the first numbers detailing how vaccination status has affected infection rates.

In those four days, 107 of the 260 county residents who tested positive for COVID-19 had been vaccinated while more than half — 142 — had not. Eleven didn’t have a known vaccination status.

McCoy also said that the “vast majority” of the vaccinated cases were young adults: 31 were in their twenties and 19 were in their thirties.

“Six vaccinated infections were from the 10- to 19-year-old age range,” said McCoy in a release. Vaccine is not authorized for anyone under age 12.

The county numbers are not surprising.

A study conducted in Barnstable County in Massachusetts, posted to the CDC website on July 30, shows a large number of “breakthrough infections” — people who were vaccinated testing positive for COVID-19 — associated with public gatherings in Provincetown in July.

Nearly three-quarters (74 percent) of the 469 infected people in the Barnstable study were vaccinated and 79 percent of them had symptoms, with the most common being a cough, headache, sore throat, myalgia, and fever.

The vaccine was effective in that only a handful of the people infected with COVID-19 were hospitalized and none died.

Testing identified the Delta variant in 90 percent of specimens from 133 patients.

Findings from the Barnstable County “suggest that even jurisdictions without substantial or high COVID-19 transmission might consider expanding prevention strategies, including masking in indoor public settings regardless of vaccination status, given the potential risk of infection during attendance at large public gatherings that include travelers from many areas with differing levels of transmission,” the study said.

McCoy’s advice on Tuesday echoed those thoughts.

“This confirms what health experts have been saying — the Delta variant is able to be contracted and spread by the vaccinated, which is why we need people to wear masks while at indoor public spaces,” said McCoy. “We also know that the vaccine dramatically reduces your chances of getting seriously ill and hospitalized, so I continue to urge people to get the shot if they haven’t already.”

As of Tuesday, 67.4 percent of Albany County’s 307,117 residents have received at least one shot, according to the state’s vaccine tracker, while 78.2 percent of county residents 18 and older have.

Statewide, 57.8 percent of New Yorkers have completed a vaccine series.

According to the Centers for Disease Control and Prevention, New York State  and Albany County both continue on Tuesday to have a high rate of transmission, the top of four categories, based on a seven-day average. A rating of “substantial” or “high” — with over 50 cases of COVID-19 per 100,000 in populations — triggers CDC guidance to wear a mask indoors in public regardless of vaccination status.

The Capital Region, of the state’s 10 regions, continues to have the highest rate of infection at 4.4 percent. Albany County’s rate, as of Monday, based on a seven-day average, was 5.1 percent, according to the state’s dashboard. Statewide, the infection rate is 3.0 percent.

On Tuesday, McCoy announced 44 new COVID-19 cases in the county: 26 did not have clear sources of infection identified, 14 had close contact with someone infected with the disease, and four reported traveling out of state.

There are now 326 active cases in the county, up from 317 on Monday. The number of Albany County residents under quarantine increased to 599 from 566.

Seventeen county residents are currently hospitalized with COVID-19, with three in intensive-care units.

Albany County’s COVID-19 death toll remains at 388.