Prevention of viral infections

Definition

A viral infection is an infection caused by a virus, an intracellular parasitic organism that infects the cells of other organisms. Common viral infections include the common cold, influenza (the flu), chickenpox, and human immunodeficiency virus (HIV) infection.

Types of Viral Infection

The common cold is an infection of the upper respiratory tract. It can be caused by several different types of viruses. Influenza is an upper respiratory tract infection that is caused by ribonucleic acid (RNA) viruses. Chickenpox is an infection that results in a skin rash. It is caused by the varicella-zoster virus. Acquired immunodeficiency syndrome (AIDS) is a chronic condition that is caused by HIV, a virus that attacks the immune system.

Prevention

Common cold. The common cold is spread through droplets in the air or by direct contact with infected surfaces. No vaccine exists to prevent the common cold. The best method of preventing the common cold is frequent handwashing, particularly before eating or preparing food.

Another way to prevent the common cold is to periodically clean with antibacterial wipes common shared surfaces, such as telephones, computer keyboards, refrigerator handles, doorknobs, and toys. A third method for preventing the common cold is to teach children to drink from their own, rather than a shared, drinking glass or cup. A fourth method of prevention is to avoid close contact with people who have a cold or other respiratory tract infection.

Influenza. Influenza is spread through droplets in the air or by direct contact with infected surfaces. The best way to prevent the flu is to get a flu shot (influenza vaccination). The flu vaccine protects against the most common types of flu viruses: seasonal influenza and the H1N1 virus (swine flu). The Centers for Disease Control and Prevention (CDC) recommends that everyone who is six months of age or older be vaccinated, although there are some exceptions.

The following persons should not get a flu vaccine without first consulting a physician: those who are allergic to eggs, have had a previous allergic reaction to the flu vaccine, have Guillain-Barré syndrome, are younger than age six months, and are already sick and who have a fever. (Vaccination is okay after the person is no longer sick.)

In addition to being vaccinated, other preventive steps include frequent handwashing, using a tissue to cover the nose or mouth when coughing or sneezing, periodically cleaning shared surfaces, avoiding close contact with people who have symptoms of a cold or flu, not sharing drinking glasses, and not going to work when sick.

Chickenpox. The best method for preventing chickenpox is getting the varicella (chickenpox) vaccine. The CDC recommends that all children and adults who do not have evidence of immunity to varicella be vaccinated. The CDC defines “evidence of immunity” as any of the following: documentation of two doses of varicella vaccine, blood tests that show immunity, laboratory confirmation of prior varicella disease, a diagnosis of chickenpox or verification of a history of chickenpox from a qualified healthcare provider, or a diagnosis of herpes zoster (shingles) or verification of a history of herpes zoster (shingles) from a qualified healthcare provider.

Some people are given the chickenpox vaccine after exposure to help prevent them from contracting the disease. According to the CDC, the chickenpox vaccine is not recommended for persons who are allergic to gelatin, who have a moderate or serious illness (vaccination is okay after the illness), who are pregnant, who are immunocompromised because of illness (such as HIV infection) or treatment (such as chemotherapy) of an illness, who have received blood or blood products within the previous three to eleven months, or who have a family history of immune deficiency.

HIV. HIV is a sexually transmitted disease, but it also can be spread through contact with infected blood or from woman to fetus during childbirth. There is no vaccination for the prevention of HIV, but pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP) improved significantly in the twenty-first century, decreasing new HIV infections. To prevent HIV, one should avoid exposure to blood or body fluids of people who are or may be infected by washing hands before and after eating, after using the toilet, and after contact with another person’s blood or body fluids; wear disposable gloves when touching anything that may have come in contact with blood or body fluids, including wound dressings; avoid sharing personal items such as razors or toothbrushes; avoid sharing drug needles; and use latex condoms during sex. Healthcare workers should use universal precautions to avoid exposure to blood or body fluids. Individuals who contract HIV should take their prescribed antiretroviral therapy medications to reduce their risk of transmitting the infection to others.

Impact

According to the National Institutes of Health, more than one billion cases of the common cold occur in the United States each year. The World Health Organization (WHO) estimates that there are between 3 million and 5 million cases of severe influenza illness each year during seasonal epidemics, resulting in 200,000 to 400,000 deaths.

According to the CDC, before the varicella vaccine was developed in 1995, about 4 million cases of chickenpox occurred each year in the United States, averaging 10,600 hospitalizations and between 100 and 150 deaths. From 1995 to 2005, the United States saw a 90 percent decline overall in the incidence of chickenpox. Between 1995 and 2002, hospitalizations from chickenpox decreased by 88 percent. Death rates dropped 66 percent from 1990 to 2001, and by the 2020s, fewer than fifty people died from chickenpox each year.

WHO estimated that around 40 million people worldwide were living with HIV infection in the mid-2020s. In 2000, 3.8 million people were newly infected with HIV, compared to 2.1 million in 2010 and 1.3 million in 2023.

Bibliography

“Chickenpox.” MedlinePlus, 8 May 2023, medlineplus.gov/ency/article/001592.htm. Accessed 24 Dec. 2024.

“Common Cold.” Mayo Clinic, 24 May 2023, www.mayoclinic.org/diseases-conditions/common-cold/symptoms-causes/syc-20351605. Accessed 24 Dec. 2024.

“Flu: What to Do if You Get Sick.” Centers for Disease Control and Prevention, 30 Aug. 2024, www.cdc.gov/flu/takingcare/index.html. Accessed 24 Dec. 2024.

“HIV/AIDS.” Mayo Clinic, 9 Feb. 2024, www.mayoclinic.org/diseases-conditions/hiv-aids/symptoms-causes/syc-20373524.

Kane, Melissa, and Tatyana Golovkina. “Common Threads in Persistent Viral Infections.” Journal of Virology, vol. 84, no. 9, 2010, pp. 4116–23, doi.org/10.1128/JVI.01905-09. Accessed 24 Dec. 2024.

Shen, Bairong. Translational Informatics: Prevention and Treatment of Viral Infections. Springer, 2022.