The first doses of a COVID-19 vaccine are expected to arrive in Connecticut in about 10 days.

Gov. Ned Lamont said Thursday that the state is expecting to receive its first shipment of the Pfizer vaccine, an anticipated 31,000 doses, on Dec. 14, and another 63,000 or so doses of the Moderna vaccine on Dec. 21. That timeline and the total number of doses is subject to change, he said.

The announcement came as many towns in southeastern Connecticut saw their greatest single-day spike in cases in months.

The U.S. Food and Drug Administration is expected to begin its review of the Pfizer vaccine on Dec. 10 and its review of the Moderna vaccine on Dec. 17. Those reviews are expected to take several days and if a vaccine is authorized by the federal government, it will begin shipping doses to the states, which will then distribute the vaccine to residents.

Pfizer now expects to ship half of the COVID-19 vaccines it originally planned for this year because “scaling up the raw material supply chain took longer than expected,” a company spokeswoman told the Wall Street Journal. The spokeswoman also said the outcome of the company’s clinical trial was later than originally projected.

Lamont said he’d learned of the Pfizer issues just before starting his 4 p.m. news briefing Thursday and was not sure whether they would affect the number of vaccine doses the state is expecting to receive later this month.

Who gets vaccinated first?

In Connecticut, the current plan is to administer the first doses of the vaccine to health care workers, including employees in long-term care facilities, as well as nursing home residents and emergency medical responders.

Lamont said the state is following the Centers for Disease Control and Prevention recommendations on who should get vaccinated first, dubbed “Phase 1a” in Connecticut. By the end of January, the “overwhelming majority” of those included in Phase 1a are expected to receive the first and second doses of the vaccine. Receiving two or three doses is typical for building immunity against many illnesses.

“Phase 1b” includes essential workers, those in congregate settings such as group homes and correctional facilities, which like nursing homes, are places where the virus has shown to quickly spread, Lamont said.

Adults aged 65 and older and those who are under the age of 65 and defined as “high risk” also are included in Phase 1b and are expected to get the vaccine between mid-January and late May.

When will it be available to the general population?

Connecticut residents under the age of 18 and those over the age of 18 who are not included in the previous phases, populations generally believed to be at lower risk of severe cases of COVID-19, will receive the vaccine during Phase 2, starting in early June.

The vaccines will be available to everyone, even those without health insurance, for no cost, said Deidre Gifford, acting commissioner of the state Department of Public Health and co-chair of the state’s vaccine advisory group.

By early fall 2021, everyone who wants to get vaccinated should be able to, she said.

State’s positivity rate hits 7.13%

Lamont reported Thursday that the state’s daily positivity rate was 7.13% the highest its been during the pandemic. He said the spike could be attributed to those traveling or gathering around the Thanksgiving holiday. Though it could be too early to tell if that led to the increase in cases officials warned about if people continued to gather and travel as usual.

The number of people hospitalized in the state due to COVID-19 decreased by 11 from a day earlier to 1,191, and the number of coronavirus-linked deaths increased by 20 to 5,111, state data shows.

Spikes seen in many southeastern Connecticut towns

Cases continue to rise in southeastern Connecticut, where several towns are experiencing the greatest single-day count of new cases in months.

Groton new cases: 39, the most since March

Montville new cases: 22, the most since June

New London new cases: 62, the most since early October, when the city had 77

Stonington new cases: 21, most since March

Submarine builder Electric Boat, which has remained open throughout the pandemic, reported 85 new confirmed COVID-19 cases this week among its employees. Confirmed cases at the company, including employees in Connecticut, Rhode Island and other locations, now stand at 608 since the pandemic began.

Outbreak at York

Nearly two dozen inmates at York Correctional Institution in East Lyme have tested positive for the coronavirus, prompting a partial lockdown there, the Associated Press reported Thursday.

That included 14 inmates with symptoms and another nine who tested positive but did not have any symptoms, Department of Correction spokeswoman Karen Martucci told the AP. She said all of those infected were in medical isolation. The facility, which has about 500 inmates, was undergoing a deep cleaning, officials said.

Martucci told the AP that free video conferencing has been made available, as the lockdown includes restrictions on prisoners’ movement and a temporary suspension of in-person, no-contact social visits.

Statewide, more than 290 inmates and nearly 140 DOC employees have COVID-19. Since the pandemic began, nearly 1,750 state inmates have tested positive for the virus and eight have died, according to the latest DOC data.

j.bergman@theday.com