Vaccines and immunizations Archive

A 2026 study suggested that getting a high-dose flu shot may reduce older adults' risk of developing Alzheimer's disease compared with a standard-dose flu shot.

Breastfeeding moms often worry about vaccines and their babies' safety. Explore how flu shots and nasal spray immunizations fit into postpartum protection.

Mild sinus or ear infections don't necessarily mean delaying vaccination. Learn when to wait on your flu shot and how fast protection builds.

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.

Learn how certain asthma medication affect your choices for the flu shot.

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.

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.