Author: Karen Weintraub and Elizabeth Weise, USA TODAY

The omicron variant is substantially more contagious and reduces the effectiveness of COVID-19 vaccines, according to a new South Africa study.

CDC experts find the benefits of Pfizer’s COVID-19 vaccine for kids 5 -11 outweigh risks. Children could begin getting shots as soon as this week.

The CDC still needs to sign off before booster shots of the Moderna and Johnson and Johnson vaccines become available.

The CDC endorsed booster shots for millions of older and high-risk Americans, opening a major new phase in the U.S vaccination drive against COVID-19.

A new report does not answer whether the SARS-CoV-2 virus jumped directly from animals to people or was accidently leaked from a Chinese research lab.

News analysis: The largest public vaccination effort ever was quickly tarnished. Even people leading the effort are at a loss to explain how and why.

Each COVID-19 infection increases the risk of a mutation that could make it more infectious, deadlier, or different enough to make vaccines not work.

Experts are concerned some won’t trust the COVID vaccine and are wary of production problems that could delay getting it to millions of Americans.

Could a vaccine arrive before the election? Nine vaccine developers are pledging to fully vet their COVID-19 candidate vaccines before asking for FDA approval.

Hydroxychloroquine fails another test against COVID-19. It doesn’t prevent serious infection, study found, though it does have annoying side effects.