What Are Vaccines?
Vaccines protect people from diseases such as chicken pox, influenza (flu), and polio. Vaccines are given by needle injection (a shot), by mouth, or sprayed into the nose. The process of getting a vaccine is called vaccination or immunization.
When a person gets a vaccine, the body responds by mounting an immune response against the particular disease. (An immune response includes all the actions of the immune system to defend the body against the disease.) In this way, the immune system learns to defend the body if the person is later exposed to the disease. Most vaccines are designed so that a person never gets a particular disease or only gets a mild case of the disease.
Vaccines not only protect individuals from disease, they protect communities as well. When most people in a community get immunized against a disease, there is little chance of a disease outbreak.
Is There a Vaccine Against HIV?
Testing is underway on experimental vaccines to prevent and treat HIV, but no HIV vaccines are approved for use outside of clinical trials. For more information about experimental HIV vaccines, read the AIDS_info_ fact sheets What is a Preventive HIV Vaccine? and What is a Therapeutic HIV Vaccine?
Even though there are no vaccines to prevent or cure HIV, people with HIV can benefit from vaccines against other diseases.
Can HIV Infection Affect the Safety and Effectiveness of Vaccines?
Yes. Damage to the immune system due to HIV can reduce the body's immune response to a vaccine. A weakened immune response makes a vaccine less effective. In people with HIV, vaccines generally work best when a person's CD4 count is above 200 copies/mm3.
By stimulating the immune system, vaccines may also cause a person's HIV viral load to increase temporarily.
Because HIV medicines strengthen the immune system and reduce HIV viral load, people with HIV may want to start antiretroviral therapy (ART) before getting vaccinated whenever possible. In some situations, however, immunizations should be given even if ART has not been started. For example, it's important for people with HIV to get vaccinated against the flu at the time of year when the risk of flu is greatest.
Are All Types of Vaccines Safe for People With HIV?
The design of a vaccine depends on several factors, such as how a microbe infects the body and how the immune system responds. For this reason, there are several types of vaccines, including live, attenuated vaccines and inactivated vaccines.
Live, Attenuated Vaccines
A live, attenuated vaccine contains a weakened but live form of a disease-causing microbe. Although the attenuated (weakened) microbe cannot cause the disease (or can cause only mild disease), the vaccine can still trigger an immune response. However, to be safe and avoid even the remote chance of getting a disease from a live, attenuated vaccine, people with HIV who have CD4 counts lower than 200 cells/mm3 or certain symptoms of HIV should not get live, attenuated vaccines.
Inactivated vaccines are made from microbes that have been killed with chemicals, heat, or radiation. There is no chance that an inactivated vaccine can cause the disease it was designed to prevent.
Do Vaccines Cause Side Effects?
Side effects from vaccines are generally minor (for example, soreness at the location of an injection or a low-grade fever) and go away within a few days. Severe reactions to vaccines are rare. Before getting a vaccine, talk to your health care provider about the benefits and risks of the vaccine and possible side effects.
Which Vaccines Are Recommended for People With HIV?
The following vaccines are recommended for people with HIV:
- Hepatitis B
- Human papillomavirus (HPV) (for those up to age 26)
- Influenza (flu)
- Pneumococcal (pneumonia)
- Tetanus, diphtheria, and pertussis (whooping cough). A single vaccine called Tdap protects adolescents and adults against the three diseases. Every 10 years, a repeat vaccine against tetanus and diphtheria (called Td) is recommended.
Additional vaccines may be recommended for a person with HIV based on the person's age, previous vaccinations, risk factors for a particular disease, or certain HIV-related factors. For more details, read this information from the Centers for Disease Control and Prevention (CDC): HIV Infection and Adult Vaccination.
What About Travel and Immunizations?
Regardless of destination, all travelers should be up to date on routine vaccinations. Those traveling to destinations outside the United States may need immunizations against diseases present in other parts of the world, such as cholera or yellow fever.
If you have HIV, talk to your health care provider about any vaccines you may need before you travel.
- If your CD4 count is less than 200 copies/mm3, your health care provider may recommend that you delay travel to give your HIV medicines time to strengthen your immune system.
- If your immune system is strong enough to get a required vaccine, your health care provider may recommend blood tests to confirm that the vaccine was effective.
To prepare for your trip, read information from CDC on Travelers with Weakened Immune Systems.
This fact sheet is based on information from the following sources:
- From CDC, the National Institutes of Health, and the HIV Medicine Association of the Infectious Diseases Society of America: Guidelines for the Prevention and Treatment of Opportunistic Infections in HIV-Infected Adults and Adolescents: Recommended Immunization Schedule for Adults and Adolescents with HIV Infection
- From CDC: CDC Health Information for International Travel: Chapter 8: Advising Travelers with Specific Needs: Immunocompromised Travelers
- From Vaccines.gov: Vaccine Basics
[Note from TheBody: This article was created by AIDSinfo, who last updated it on Feb. 8, 2018. We have cross-posted it with their permission.]