Vaccines and immunizations Archive

Scientists are trying to create a vaccine that would protect people against all different strains of the influenza (flu) virus. These vaccines are being designed to target parts of the flu virus that don't change regularly and so are consistent across all strains. The perfect vaccine would also prevent symptoms (since current vaccines help prevent hospitalization and death, but not symptoms), and its effects would last for a lifetime. While such a vaccine is still many years away from reality, improved flu vaccines are expected in the meantime.

There are currently nine trials of vaccines for Alzheimer's disease under way. All of them are in people with mild Alzheimer's or with the pre-Alzheimer's condition called mild cognitive impairment. All of the vaccines are designed to encourage the immune system to remove protein deposits from the brain. Most experimental vaccines are given by injection; one being tested at Harvard Medical School uses a nasal spray. It will be several years before we know if any of them will work.

Arm tenderness is the most common side effect after vaccination. The injection stretches muscle fibers and triggers an immune response, causing discomfort. People can counter pain by moving the injected arm afterward and applying a cool compress or ice pack.

A 2025 study suggested that getting the shingles vaccine can significantly reduce the likelihood of developing dementia, especially among women.

A 2025 study found that the shingles vaccine reduced the risk of developing dementia by 20%. The study supports (but doesn't absolutely prove) the theory that infections may be one cause of Alzheimer's disease and possibly other forms of dementia.

Measles have made a comeback, with outbreaks in many states. The infection is extremely contagious and can be deadly. Most people getting measles were not vaccinated against it. Adults should get the vaccine if they were born after 1957 and didn't receive two doses. They should get a booster shot if they received the vaccine between 1963 and 1968, when the vaccine used was not as strong as the one that's been given since 1968.

It's fairly common for a medical treatment to cause side effects - but far more rarely, a side effect provides an unexpected benefit. This might be the case for the shingles vaccine, as evidence is mounting that it might also reduce the risk of dementia.

In October 2024, the CDC lowered the age for healthy adults to receive a pneumococcal vaccine to 50 from 65. It also recommends a second dose of the 2024-25 COVID vaccine for people 65 and older and immunocompromised people six months after their last dose.

Avoiding germs that cause respiratory and gastrointestinal illnesses is especially important during the winter months, when cases are on the rise. Learn which strategies keep you safe.