The recent announcement of Pennsylvania’s first measles-related deaths in decades has ignited a public feud among politicians and health officials who disagree over the role of the contagious disease in the fatalities.

The biggest obstacles to President Donald Trump’s order on vaccines may be the logistical challenges it poses for parents, health providers and drugmakers in the United States.

Doctors worry that President Donald Trump’s new executive order on vaccines will stoke fear and confusion among parents at a time when measles is raging, immunization rates are falling and children are heading back to school.

Measles outbreaks are raising new concerns in schools across the United States as the CDC reports the highest annual number of cases in more than three decades.

Gunfire aimed at the U.S. Centers for Disease Control and Prevention by a man authorities say was angry over COVID-19 vaccines is the latest in a string of violence and harassment directed at health care workers amid hostility lingering from the pandemic.

Health Secretary Robert F.

U.S. Health Secretary Robert F.

U.S. Health Secretary Robert F.

U.S. Health Secretary Robert F.

Federal health officials will no longer routinely approve annual COVID-19 shots for younger adults and children who are healthy.

There’s new uncertainty about updated COVID-19 shots this fall after the Trump administration’s handling of a shot from Novavax.

A video shows a Texas doctor, who has been treating children in a measles outbreak, with a measles rash on his face in a clinic while caring for patients a week before he met with Health Secretary Robert F.

The top vaccine official with the Food and Drug Administration has resigned and criticized the nation's top health official for allowing “misinformation and lies” to guide his thinking behind the safety of vaccinations.

Robert F.

Food and Drug Administration nominee Dr. Marty Makary is known for his contrarian views and fiery criticism of traditional medical institutions.

Newly installed Health and Human Services Secretary Robert F.

The U.S. is poised to make COVID-19 vaccinations more like a yearly flu shot.

A federally funded study has found a possible link between aluminum in some childhood vaccines and persistent asthma, but experts say the study has several shortcomings.

A new government report shows Pfizer’s COVID-19 vaccine gave children 5 and older strong protection against hospitalization and death even during the omicron surge.

What comes next in the COVID pandemic? The simple truth is that we don’t know yet.

The omicron-fueled surge that is sending COVID-19 cases rocketing in the U.S. is putting children in the hospital in record numbers.

The outside panel of experts voted unanimously in favor of offering booster doses of the Johnson & Johnson vaccine at least two months after the first dose.

A panel of U.S. health advisers has endorsed booster doses of Johnson & Johnson’s single-shot COVID-19 vaccine.

President Joe Biden’s administration drew up a strategy to contain one coronavirus strain, then another showed up that’s much more contagious.

The world’s leading COVID-19 vaccines may offer lasting protection that diminishes the need for frequent booster shots.

FILE - This September 2020, file photo provided by Johnson & Johnson shows a pharmacist preparing to give an experimental COVID-19 vaccine. (Johnson & Johnson via AP, File)WASHINGTON – U.S. health advisers endorsed a one-dose COVID-19 vaccine from Johnson & Johnson on Friday, putting the nation on the cusp of adding an easier-to-use option to fight the pandemic. One challenge in rolling out the new vaccine will be explaining how protective the J&J shot is after the astounding success of the first U.S. vaccines. One dose of the J&J vaccine was 85% protective against the most severe COVID-19. On Sunday, a CDC panel is expected to meet to recommend how to best prioritize use of the J&J vaccine.

FILE - This Dec. 2, 2020 photo provided by Johnson & Johnson shows vials of the Janssen COVID-19 vaccine in the United States. Still, he was encouraged that one dose of the J&J vaccine appears as good at preventing serious illness as its two-dose competitors. Across all countries, the analysis of the J&J vaccine showed protection began to emerge about 14 days after vaccination. Like other COVID-19 vaccines, the main side effects of the J&J shot are pain at the injection site and flu-like fever, fatigue and headache. If the FDA clears the J&J shot for U.S. use, it will not boost vaccine supplies significantly right away.

FILE - This Dec. 2, 2020 photo provided by Johnson & Johnson shows vials of the Janssen COVID-19 vaccine in the United States. “I was reassured” that despite different variants, the J&J shot still protected against serious illness, said Dr. Jesse Goodman of Georgetown University, a former FDA vaccine chief. Across all countries, the analysis of the J&J vaccine showed protection began to emerge about 14 days after vaccination. Like other COVID-19 vaccines, the main side effects of the J&J shot are pain at the injection site and flu-like fever, fatigue and headache. AdIf the FDA clears the J&J shot for U.S. use, it will not boost vaccine supplies significantly right away.

The U.S. is considering a second vaccine, made by Moderna Inc., that could roll out in another week. Friday, Sanofi and GSK announced a months-long delay after early tests showed their vaccine didn’t work well enough in older adults. About 3 million doses of the Pfizer-BioNTech vaccine are expected in the first shipments around the country, according to officials with Operation Warp Speed, the Trump administration’s vaccine development program. Expected to follow health workers and nursing homes are other essential workers, older adults and people at high risk because of other health problems. If emergency use of Moderna’s vaccine also is authorized, the U.S. expects to vaccinate 20 million people by the end of December.

Trucks will roll out Sunday morning as shipping companies UPS and FedEx begin delivering Pfizer’s vaccine to nearly 150 distribution centers across the states, said Army Gen. Gustave Perna of Operation Warp Speed, the Trump administration’s vaccine development program. Initially, about 3 million doses were expected to be shipped nationwide. Perna compared the vaccine distribution effort to D-Day, the U.S.-led military offensive that turned the tide in World War II. The vaccine was timed to arrive Monday so health workers could receive the shots and begin giving them, Perna said. The announcement came after revelations that the White House opted not to lock in an additional 100 million doses of Pfizer’s vaccine for delivery in the second quarter of 2021.

Documents created by Pfizer for the meeting with the Food and Drug Administration advisory panel, as Pfizer seeks approval for emergency use of their COVID-19 vaccine, are seen on Thursday, Dec. 10, 2020. Pfizer has said it will have about 25 million doses of the two-shot vaccine for the U.S. by the end of December. Next week, the FDA will review a second vaccine, from Moderna and the National Institutes of Health, that appears about as protective as Pfizer-BioNTech’s shot. The company proposed gradually moving those patients to the vaccine group, with priority based on age, health conditions and other factors. Pfizer must still show whether the vaccine works in children younger than 16 and in pregnant women.

Pfizer announced Wednesday, Nov. 18, 2020, more results in its ongoing coronavirus vaccine study that suggest the shots are 95% effective a month after the first dose. The companies also have begun “rolling submissions” for the vaccine with regulators in Europe, the U.K. and Canada and soon will add this new data. Pfizer and BioNTech had initially estimated the vaccine was more than 90% effective after counting a group of the earliest infections that occurred in its final-stage testing. Pfizer would handle shipping of its own doses; the warp speed program will help with support and distributing additional companies' vaccines if and when they become available. Pfizer and BioNTech said they expect to produce up to 50 million vaccine doses globally in 2020 and up to 1.3 billion doses in 2021.

University of Hong Kong scientists claim to have the first evidence of someone being reinfected with the virus that causes COVID-19. The man had mild symptoms the first time and none the second time; his more recent infection was detected through screening and testing at the Hong Kong airport. It shows that some people do not have lifelong immunity to the virus if they've already had it, To said. If there is a reinfection, it suggests the possibility there was residual immunity ... that helped protect the patient from getting sick again, Goodman said. ___The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institutes Department of Science Education.