Vaccines and immunizations Archive

In the US, widespread vaccination halted the ongoing spread of measles more than 20 years ago, but recent outbreaks have flared in over 20 US states, leading to hospitalizations and at least two deaths. Measles is highly preventable - here's what you need to know.

Science has made astonishing progress in the past 60 years in many areas. Examples include the ability to repair certain defective genes, use stem cells to treat certain diseases, detect and fight many cancers, fight viruses with medications, make organ transplants work, and prevent disease with vaccines and lifestyle changes. Thanks to technological advances, doctors can also see clearly inside the body and use artificial intelligence to speed the development of new medications.

A 2025 study suggests that respiratory syncytial virus (RSV) can lead to heart-related complications, such as a heart attack, chronic heart failure, or an irregular heartbeat-even in people without a previous heart condition.

A 2025 study found that people who had received a shingles vaccination had lower risks for stroke and various types of heart disease, including heart failure and heart attacks, compared with people who didn't receive a shingles vaccine.

Getting vaccinated against influenza (flu), COVID-19, and pneumonia is especially important for people who have cardiovascular disease. The coughing and congestion that commonly occur with respiratory infections can make breathing more difficult, and the potential drop in oxygen puts added stress on the heart. Serious infections sometimes trigger sepsis, which happens when the immune system is overwhelmed or goes into overdrive, causing symptoms such as a rapid heart rate, very fast breathing, and low blood pressure. These complications can lead to a heart attack.

With influenza virus, a new vaccine must be developed each year to adapt to the virus's changing structure.

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.

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.

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