The most important thing is to get vaccinated no matter the circumstances, doctors say.

Pfizer announced Thursday that its vaccine candidate for respiratory syncytial virus was 85.7% effective in preventing lower respiratory tract illness in older adults.

Public health experts tell ABC News which vaccine is used to protect against polio and why most Americans are unlikely to be infected with the disease.

Children in London are being offered polio vaccine boosters after sewage samples with the virus were found in multiple areas across the city.

New York health officials said a patient was infected with vaccine-derived polio. Here's what that means.

The vaccine will mainly be available to healthcare workers and lab personnel.

An independent CDC advisory panel will vote Tuesday on whether to recommend Pfizer's COVID-19 vaccine for children ages 5 to 11 in the U.S.

The vaccination rate nationwide is down to the lowest level since January.

The CDC found a more than 80% decline in HPV infections nationally.

The Pfizer and Moderna vaccines are safe and effective in pregnant and lactating women and those women are able to pass protective antibodies to their newborns.

Clinical studies showed that the one-shot vaccine provides strong protection against COVID-19, including 85% effectiveness against severe illness and preventing 100% of hospitalizations and death.

The British government will begin a new trial to test mixing different types of COVID-19 vaccines, in which participants will receive one dose followed by a second booster shot of a different vaccine.

One-third of parents are delaying immunization

An Illinois pediatrician who died by suicide last year may have forged patient's vaccination medical records, according to investigators.