A doctor loads a dose of Pfizer COVID-19 vaccine into a syringe in a Dec. 2, 2021, file photo at a mobile vaccination clinic in Worcester, Mass. (AP Photo / Steven Senne, File)

The Centers for Disease Control and Prevention's advisers voted that a booster was safe for younger teens and should be offered to them once enough time — five months — has passed since their last shot.

Dr. Anthony Fauci, White House Chief Medical Advisor and Director of the NIAID, and Dr. Rochelle Walensky, Director of the Centers for Disease Control and Prevention, arrive to participate in the White House COVID-19 Response Team’s regular call with the National Governors Association in the South Court Auditorium in the Eisenhower Executive Office Building on the White House Campus, Dec. 27, 2021, in Washington. (AP Photo / Carolyn Kaster, File)

The decision to keep the initial definition, established more than a year ago when the vaccines first rolled out, means that federal vaccination mandates for travel or employment won’t require a booster dose.

A health worker administers a dose of a Moderna COVID-19 vaccine during a vaccination clinic at the Norristown Public Health Center in Norristown, Pa., Tuesday, Dec. 7, 2021. (AP Photo / Matt Rourke, File)

Worried that a new COVID-19 wave could overwhelm understaffed U.S. hospitals, federal officials on Thursday loosened rules that call on health care workers to stay out of work for 10 days if they test positive.

Travelers wait for a shuttle but to arrive at the Los Angeles International Airport in Los Angeles, Monday, Dec. 20, 2021. The Los Angeles County Department of Public Health reported more than 3,500 new cases of COVID-19 on Sunday as the number of daily new cases tripled over the week. (AP Photo / Jae C. Hong)

The Centers for Disease Control and Prevention numbers showed nearly a six-fold increase in omicron’s share of infections in only one week.

Katie Lucey administers a COVID-19 test on her son Maguire at a PCR and Rapid Antigen COVID-19 coronavirus test pop up on Wall Street in New York on Thursday, Dec. 16, 2021. (AP Photo / Ted Shaffrey)
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The Centers for Disease Control and Prevention decided to more firmly embrace the approach, already used by many school districts, after research of such policies in the Chicago and Los Angeles areas found COVID-19 infections did not increase when using the approach.

A member of the Philadelphia Fire Department prepares a dose of the Johnson & Johnson COVID-19 vaccine at a vaccination site setup in Philadelphia, on March 26, 2021. (AP Photo / Matt Rourke, File)

Most Americans should be given the Pfizer or Moderna vaccines instead of the Johnson & Johnson shot that can cause rare but serious blood clots, U.S. health officials said Thursday.

A medical staff member prepares the Pfizer-BioNTech COVID-19 vaccine at Tudor Ranch in Mecca, Calif. on Jan. 21, 2021 (AP Photo / Jae C. Hong, File)

The U.S. and many other nations already were urging adults to get booster shots to pump up immunity that can wane months after vaccination, calls that intensified with the discovery of the worrisome new omicron variant.

A syringe is prepared with the Pfizer COVID-19 vaccine at a clinic at the Reading Area Community College in Reading, Pa., on Sept. 14, 2021. (AP Photo / Matt Rourke, File)

The Centers for Disease Control and Prevention must agree to expand Pfizer and Moderna boosters to even healthy young adults. Its scientific advisers were set to debate later Friday.

This Wednesday, March 31, 2021 file photo shows empty vials of Johnson & Johnson’s one-dose COVID-19 vaccine at a mobile vaccination site in Uniondale, N.Y. (AP Photo / Mary Altaffer)

Millions more Americans can get a COVID-19 booster and choose a different company’s vaccine for that next shot, federal health officials said Thursday.

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More than 650 people have been infected with salmonella oranienburg nationwide, including 37 people in Illinois, according to federal health officials. 

(AP Illustration / Peter Hamlin)

When COVID-19 vaccines were first rolling out in the U.S., the Centers for Disease Control and Prevention recommended waiting 14 days between the shots and other immunizations as a precaution. But the agency has since revised its guidelines and says the wait is unnecessary.

(Andrew Lichtenstein / Corbis News / Getty Images)

Provisional data from the CDC’s National Center for Health Statistics, released early Wednesday, suggest the homicide rate for the United States rose 30% between 2019 and 2020. 

In this Jan. 8, 2021, file photo, a pharmacist prepares a syringe of the Pfizer vaccine for COVID-19, at Queen Anne Healthcare, a skilled nursing and rehabilitation facility in Seattle. (AP Photo / Ted S. Warren, File)

The Centers for Disease Control and Prevention on Thursday endorsed booster shots for millions of older or otherwise vulnerable Americans, opening a major new phase in the U.S vaccination drive against COVID-19.

The University of Chicago reported a COVID-19 outbreak at the beginning of April. (WTTW News)
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Students at an unidentified Chicago university who traveled over spring break sparked an outbreak of COVID-19 that sickened 158 people, according to a report from the Centers for Disease Control and Prevention released Thursday.

(Credit: Joe Raedle / Getty Images)

Due to the surge of COVID-19 cases, the director of the U.S. Centers for Disease Control and Prevention is asking unvaccinated Americans not to travel during the Labor Day holiday weekend.

In this Aug. 4, 2021, file photo, housing advocates protest the eviction moratorium in New York. (AP Photo / Brittainy Newman, File)

Tenant advocates and court officials were gearing up Friday for what some fear will be a wave of evictions and others predict will be just a growing trickle after a U.S. Supreme Court action allowing lockouts to resume.