In Alaska’s Covid Crisis, Doctors Must Decide Who Lives and Who Dies

Amid the nation’s worst Covid-19 outbreak, patients are trapped in remote communities and doctors are prioritizing treatment based on who is most likely to survive.

Is the Coronavirus Getting Better at Airborne Transmission?

The Alpha variant traveled more efficiently in small droplets, two new studies found. The Delta variant may have continued this evolution.

U.S. Coronavirus Death Toll Surpasses 700,000 Despite Wide Availability of Vaccines

The latest Covid-19 deaths were concentrated in the South, and included more younger people than before. Every age group under 55 saw its highest death toll of the pandemic this August.

In Portugal, There Is Virtually No One Left to Vaccinate

Portugal is among the most highly vaccinated countries in the world. Vice Adm. Henrique Gouveia e Melo, who led the campaign, said there was a key to his success: Keep politics out of it.

How Accurate Are At-Home Covid Tests?

When used correctly, many at-home rapid tests are good at detecting people carrying high levels of the virus.

Does My Mask Protect Me if Nobody Else Is Wearing One?

Masks work best when everyone in the room has one on, but you’ll still benefit from masking up even when those around you aren’t.

Federal Panel Recommends Booster Shots, Opening New Campaign Against the Virus

Scientific advisers to the C.D.C. endorsed additional doses of the Pfizer-BioNTech vaccine for older Americans but not for health care workers, in a possible rift with regulators.

Has Covid Cost Australia Its Love for Freedom?

Half the country is locked down, and its borders remain closed. But most Australians are willing to make these sacrifices in pursuit of a collective freedom from fear of the virus.

At Covid Summit, Biden Sets Ambitious Goals for Vaccinating the World

But his plans face a tough road as pressure grows for big pharmaceutical companies to share their vaccine technologies with poorer nations.

‘I Just Cry All the Time’: Non-Covid Patients Despair Over Delayed Care

In areas inundated with coronavirus patients, hospitals have postponed treatments and surgeries for people with other serious conditions.

Does My Mask Protect Me if Nobody Else Is Wearing One?

Masks work best when everyone in the room has one on, but you’ll still benefit from masking up even when those around you aren’t.

Covid Vaccine Prompts Strong Immune Response in Younger Children, Pfizer Says

Vaccinated kids aged 5 to 11 showed evidence of protection against the virus, the company said. The data must be reviewed by the F.D.A. before children can be inoculated.

Covid Vaccine Prompts Strong Immune Response in Younger Children, Pfizer Says

Vaccinated kids aged 5 to 11 showed evidence of protection against the virus, the company said. The data must be reviewed by the F.D.A. before children can be inoculated.

Covid Vaccine Prompts Strong Immune Response in Younger Children, Pfizer Says

Vaccinated kids aged 5 to 11 showed evidence of protection against the virus, the company said. The data must be reviewed by the F.D.A. before children can be inoculated.

Opinion | Rich Countries Worry About Booster Shots. They Should Be Worried About Africa.

Just 20 percent of people in low- and lower-middle-income countries have had a Covid-19 vaccine dose — versus 80 percent in richer countries.

U.S. Booster Policy Is in Flux as Studies Add to Dissent

A week before President Biden’s plan is to roll out, scientists are at odds about whether extra coronavirus shots are needed and for whom.

New Study of Covid Booster Shots Fans Debate Over Benefits

Independent experts, including government scientists, were skeptical of the research from Israel, which included limited data over a short period.

As India’s Lethal Covid Wave Neared, Politics Overrode Science

The country’s top science agency tailored its findings to fit Prime Minister Narendra Modi’s optimistic narrative despite a looming crisis, researchers say.

N.Y.C. Virus Cases Appear to Plateau. Could an Uptick Lie Ahead?

As students head back to school, experts say that the city’s third coronavirus wave may be ebbing.

Biden’s Sweeping Vaccine Mandates Infuriate Republican Governors

Some employers and business groups welcomed the new coronavirus requirements, but many G.O.P. leaders issued outright condemnations.