Overview of Viral Infections

A viral infection is a sickness caused by a virus.

• Viruses can get into your body through breathing air (for example, the virus that causes COVID-19), having sex, touching something with viruses on it, or being bitten by a bug such as a mosquito or tick

• Viruses usually infect only one type of cell—for example, the virus that causes the common cold infects only cells in your nose, mouth, and throat

• When you get a virus, your white blood cells attack it—these cells also remember how to fight it if the same virus gets into your body again

• Many viruses make you sick shortly after you get them and then go away

• Some viruses don't go away and can make you sick a long time after you get them (for example, HIV and herpesvirus)

• Antibiotics, which treat bacterial infections, can’t treat viral infections

Certain viruses change how your cells work, which can lead to cancer. For example, the hepatitis B and C viruses can lead to liver cancer. HPV (human papillomavirus) can lead to cervical cancer.

Doctors can tell if you have certain common viral infections based on your symptoms. They may also do:

• Blood tests

• Cultures (when doctors take a sample from your body and try to grow germs from it in a lab)

Doctors can’t usually do much to treat many viruses. They’ll mainly suggest medicines to treat your symptoms and help you feel better. For example, if you have a stuffy nose, doctors may tell you to take a decongestant.

For some viruses, doctors can give you an antiviral medicine. Antiviral medicines are used for only a few viruses, including:

• COVID-19

• Hepatitis viruses

• Herpesviruses

• HIV

• Influenza (flu)

Antibiotics are drugs that kill bacteria. Antibiotics do not kill viruses.

• Take good care of your health—for example, wash your hands often with soap and water and practice safe sex

• Get recommended vaccines

Vaccines are shots that teach your immune system how to fight off certain infections. You usually get vaccines before you're exposed to an infection.

For some viruses, you can get a shot after you're exposed to it. These shots contain antibodies (immunoglobulins) that help fight off the virus. For example, there are immunoglobulin shots for:

• Hepatitis

• Rabies