The city of Boston placed more than 800 unvaccinated workers on unpaid leave Tuesday, tightening enforcement of a mandate put in place by acting Mayor Kim Janey.

City officials last week warned approximately 1,400 workers they were out of compliance with the requirement, according to the mayor's office. By Tuesday, 812 people were handed their leave.

In a written statement, a spokesperson said the city was "leading by example with a phased-in vaccination or regular testing mandate."

Drugmaker Merck asked U.S. regulators Monday to authorize its pill against COVID-19 in what would add an entirely new and easy-to-use weapon to the world's arsenal against the pandemic.

If cleared by the Food and Drug Administration — a decision that could come in a matter of weeks — it would be the first pill shown to treat COVID-19. All other FDA-backed treatments against the disease require an IV or injection.

An antiviral pill that people could take at home to reduce their symptoms and speed recovery could prove groundbreaking, easing the crushing caseload on U.S. hospitals and helping to curb outbreaks in poorer countries with weak health care systems. It would also bolster the two-pronged approach to the pandemic: treatment, by way of medication, and prevention, primarily through vaccinations.

The COVID-19 vaccine may have helped prevent hundreds of deaths and thousands of infections among Massachusetts seniors in a five-month span, federal health officials said Tuesday.

In a new report, the U.S. Department of Health and Human Services projected that the immunization may have shielded 900 Bay Staters who are enrolled in Medicare from death, prevented another 2,500 from hospitalization and helped 6,000 avoid contracting the highly infectious virus between January and May.

Nationally, researchers estimated that the vaccine rollout was linked to the prevention of 265,000 infections, 107,000 hospitalizations and 39,000 deaths among Medicare beneficiaries during the first five months of 2021.

It's tough to be a school nurse right now.

Concerns about COVID dominate their days. This year, all students are back in the classroom, so there's almost no physical distancing. That's even though the highly contagious delta variant continues to spread.

Drugmaker Merck said Friday that its experimental COVID-19 pill reduced hospitalizations and deaths by half in people recently infected with the coronavirus and that it would soon ask health officials in the U.S. and around the world to authorize its use.

If cleared, the drug would be the first pill shown to treat COVID-19, a potentially major advance in efforts to fight the pandemic. All COVID-19 therapies now authorized in the U.S. require an IV or injection.

Merck and its partner Ridgeback Biotherapeutics said early results showed patients who received the drug, called molnupiravir, within five days of COVID-19 symptoms had about half the rate of hospitalization and death as patients who received a dummy pill. The study tracked 775 adults with mild-to-moderate COVID-19 who were considered higher risk for severe disease due to health problems such as obesity, diabetes or heart disease.

A day before the state's COVID-19 emergency paid sick leave program was set to expire, Gov. Charlie Baker on Wednesday approved an extension of the program until April 1.

The Legislature sent the extension bill (H 4127) to Baker's desk on Monday. The program was first authorized under a law passed in May with the intention of giving workers time to quarantine, recover, get vaccinated, or help a family member dealing with the coronavirus. It was set to expire Sept. 30.

The May law created a new $75 million emergency COVID-19 sick leave program offering workers up to one week of paid leave, capped at $850. Senate President Karen Spilka and House Speaker Ronald Mariano said this week that an extension would "help Massachusetts continue its progress towards full recovery."

The union representing 4,000 Massachusetts correction officers has filed a federal complaint to try to block Gov. Charlie Baker's coronavirus vaccine mandate.

The Massachusetts Correction Officers Federated Union filed the 19-page complaint Wednesday, saying the governor's mandate violates their collective bargaining agreement (CBA).

"The mandate imposes an unreasonable, coercive condition on employees covered by the CBA: they must choose between a) exercising their constitutional right to decline unwanted medical treatment but thereby lose their reasonably-expected employment security, or b) forfeiting their right to decline unwanted medical treatment in order to retain their constitutionally-protected employment security," attorneys wrote in the complaint.

Among other things, the complaint argues that being vaccinated does not fully protect the correction officers or others from the virus because there are "breakthrough cases" where those fully vaccinated have become infected. It also argues that prisoners are not required to get the shot.

"Requiring that DOC employees receive the vaccine thus does not guarantee that employees do not get sick and die from the virus, and it does not insure or guarantee that inmates or fellow employees will not become infected through contact with DOC employees," the complaint reads.

The complaint names Baker and Massachusetts Correction Commissioner Carol Mici as defendants.

Under Baker's mandate,  state workers must get vaccinated or seek an exemption by Oct. 17. If they don't, they could face discipline, including termination.

Massachusetts State Police recently lost their legal challenge to the state vaccine mandate in Superior Court. They were seeking to delay the mandate so they could negotiate the terms and potentially allow those who did not want to be vaccinated to instead wear masks and be tested regularly. The judge ruled that the union's interest is "outweighed" by the state's interest in protecting the health and safety of its workforce and the general public.

Representatives from the union, the governor's office or Department of Correction have not responded to requests for comment.