Coronavirus Watch: A 4th vaccine shot?

Adults with pre-existing medical conditions who have already received three shots of the Moderna or Pfizer-BioNTech vaccines will be able to get a fourth shot, federal health officials say.

"People who are moderately and severely immunocompromised may receive a total of four COVID-19 vaccine doses," the CDC said in its guidelines updated Tuesday.

The CDC authorized a third dose for immunocompromised people 18 and older in August, as some medical conditions and treatments can make it difficult for immunocompromised people to build and retain immunity.

The fourth shot should be received at least six months after the third, the CDC said.

It's Wednesday, and this is Coronavirus Watch from the USA TODAY Network. Here's more news to know:

• An FDA advisory panel voted Tuesday to authorize the Pfizer-BioNTech vaccine for kids 5 to 11. Before kids can actually get shots in arms, the FDA will have to sign off on the recommendation, an independent CDC advisory panel will review the data, and then the CDC director would have to give her clearance.
• Pharmaceutical giant Merck announced a licensing agreement to provide "affordable" global access to its COVID-19 antiviral treatment, molnupiravir. 
• Ocugen Inc., maker of the COVAXIN vaccine, is hoping to enter the U.S. market, this time with a traditional type of shot that has already been delivered more than 100 million times in India.
• Brazilian President Jair Bolsonaroshould face a series of criminal indictments for his handling of the COVID-19 pandemic, a Brazilian Senate committee said Tuesday.
• Double-vaccinated Australians will be allowed to travel abroad and/or return home starting Monday, the nation's health minister announced. Many families have been split apart by the tight border closure that went into effect in March 2020.

Today's numbers: The U.S. has reported more than 45.6 million COVID-19 cases and 738,000 deaths, according to data from Johns Hopkins University. Worldwide, there have been more than 244.7 million cases and more than 4.9 million deaths. About 66% of people in the U.S. have received at least one vaccine shot, and about 57% are fully vaccinated, according to the CDC. Among U.S. adults, 80% have received at least one shot, and about 69% are fully vaccinated.

Tracking the pandemic: See the numbers in your area here. See where cases are rising here. See vaccination rates here. And here, compare vaccinations rates worldwide and see which countries are using which vaccines.

– Grace Hauck, USA TODAY breaking news reporter, @grace_hauck