Immune and infectious diseases Archive

Over-the-counter cold remedies can be helpful, but they must be carefully considered before use. They contain drugs that can cause serious side effects, interact with other medications, and worsen certain health conditions. For example, decongestants can help ease a stuffy nose but also can increase blood pressure and heart rate. And cough suppressants can help someone stop coughing, but taking too much can cause dizziness, confusion, or even changes in mood or thinking.

A 2025 study of 250 people found that the brain can tell the immune system to prepare for impending infection even before a microbe enters the body. Scientists asked volunteers to don virtual reality headsets that showed various virtual people approaching them. Some of those approaching appeared to be healthy and others appeared to be sick. Brain scans and blood tests showed that participants' brains activated their immune systems when a virtual sick person simply came near them.

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.

In a 2025 study of nearly a million people with diabetes, those who took GLP-1 drugs had a reduction of 10% to 20% in heart failure, cardiac arrest, lung failure and pneumonia, and dementia, compared with people who took other diabetes medications.

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.

Eating a variety of flavonoid-rich foods may offer greater protection against cardiovascular disease and cancer than eating only a few high-flavonoid foods, according to a 2025 study.

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.

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.

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.