Immune and infectious diseases Archive

About half of Americans have herpes simplex virus type 1, which causes cold sores that can recur periodically. The virus can't be eliminated, but topical and oral treatments can help. In addition, people can avoid cold sore triggers such as stress or fatigue.

Shingles occurs when the dormant chickenpox virus reactivates, causing tingling, burning, and a painful, blistering rash. Shingles can affect anyone who has had chickenpox, with higher risk after age 50 and in people with weakened immunity. Diagnosis and treatment within three days of the rash appearing can shorten the illness and reduce severity. Most people recover completely from shingles, but there may be complications, such as post-herpetic neuralgia, which is pain that can be severe and long-lasting. Vaccination is the best way to prevent shingles and its complications.

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.

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.

Several factors increase the risk for complications from COVID-19 or influenza and should prompt someone to request an antiviral medication as soon as possible, even if they have been vaccinated or have had the infections before. The risk factors are age (being 65 or older), an impaired immune system, and underlying conditions (especially heart or lung disease). Pregnant women also are at increased risk for severe influenza and COVID, and should consider taking an antiviral.

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.

The flu virus triggers bodywide aches and pain by causing inflammation. People can ease flu aches by staying hydrated; taking warm showers; and using over-the-counter anti-inflammatory drugs such as ibuprofen (Advil, Motrin) or naproxen (Aleve).

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