More than 730,000 Americans have died from COVID-19 while over 4.9 million people have died from the disease worldwide, according to real-time data compiled by the Center for Systems Science and Engineering at Johns Hopkins University.

Just 66.8% of Americans ages 12 and up are fully vaccinated against COVID-19, according to data from the CDC.

The FDA authorized booster shots for the Moderna and Johnson & Johnson vaccines for some populations Wednesday.

Moderna's vaccine can be administered at least six months after the second dose for people ages 65 and up and those ages 18 through 64 who either are at high risk of severe COVID-19 infection or have occupational exposure to the virus, the FDA said.

The J&J booster can be administered at least two months after the single-dose shot to those ages 18 and up, the agency said.

The FDA, which authorized Pfizer's booster dose last month, also said it will allow people to mix booster doses.