Immunizations (vaccines) expose the immune system to a potential future threat in order to “train” it to respond strongly later on. Vaccines contain small amounts or inactivated versions of common illnesses. Getting vaccinated may help us avoid getting certain conditions entirely. Or we may experience a much milder version of the illness if we do get exposed.1
How do vaccines work?
When a person receives a vaccine, their body mounts an immune response. The body creates proteins or immune cells designed to target whatever illness the vaccine is training the body to fight. Later on, if a person comes in contact with that same illness in the real world, their body is prepared to combat the infection before getting very sick.1,2
Vaccines require an active, healthy immune system to train. So those with a weakened immune system (such as people with HIV) may not have as strong a response to vaccines. Some people may even have a bad reaction to certain vaccines if their immune system is too weak.2
Most people living with HIV, including adults and children, can receive the same routine vaccines that the general population gets. Exceptions are if the person with HIV has a very low CD4 count (number of white blood cells that fight infection) or another barrier to vaccination.2
Vaccines as part of HIV care
Getting vaccinated is important in HIV care. When your immune system is weakened, common illnesses like flu (influenza) or pneumonia may become life-threatening. Getting vaccinated to prevent these illnesses from happening in the first place can greatly impact your overall health if you have HIV.2,3
What vaccines are not recommended?
Vaccines come in several forms. They may be injected via a shot under the skin or into a muscle, given by mouth, or sprayed into the nose. Different vaccines have different methods of administration. They also have different timelines for when they should be given.1
Some vaccines are inactivated versions of the illness they are designed to protect against. For a person living with HIV, there is not much risk in getting these. The main concerns with an inactivated vaccine are infections at the injection site or a weakened response to the vaccine due to a weakened immune system.2,3
Attenuated vaccines
Other vaccines are live, attenuated vaccines. These vaccines may not be recommended for a person living with HIV if that person's CD4 count is too low.1
Live, attenuated vaccines contain weakened forms of the illnesses they are designed to protect against. In a person with a healthy immune system, these weakened illnesses may have no impact at all. In some cases, they may cause a mild form of the illness. But the illness is much less severe than if the person was to get it on their own.1
For most people, getting a mild form of the illness is not a problem. But a person with HIV who has a low CD4 count could get very sick. This is why some live vaccines may not be recommended for those with a CD4 count less than 200 cells/microliter. These live vaccines include the:2-6
- Measles, mumps, and rubella vaccine
- Varicella (chickenpox) vaccine
- Zoster (shingles) vaccine
- Live attenuated influenza vaccine
If you are unsure whether you should receive a particular vaccine, ask your doctor.1
What vaccines should a person living with HIV receive?
As mentioned, as long as a person with HIV has a relatively high CD4 count and/or is taking ART (antiretroviral therapy, drugs used to treat HIV) to keep counts high, they should not have a problem getting the vaccines recommended to the general public. These include:2-5,7
- COVID-19 vaccine
- Flu vaccine, such as Fluarix®
- Tetanus, diphtheria, and pertussis vaccine, such as Adacel®
- Human papillomavirus vaccine (Gardasil® 9)
- Hepatitis B vaccine, such as Heplisav-B®
- Shingles vaccine (Shingrix®)
Other vaccines may be recommended in specific situations, or if someone may be exposed to a less common illness.3
When to get vaccinated
The best time for a person with HIV to get a vaccine is when their immune system is relatively strong. This occurs when their CD4 counts are high or when they are regularly taking and responding to ART. However, it may be beneficial to give some vaccines regardless of CD4 count, such as the yearly flu vaccine, to help protect them as much as possible.2-5
If a vaccine is given during a time when the immune system is weaker, the body’s response to the vaccine may not be strong. That means the person getting the vaccine may not have achieved full immunity. In that case, the vaccine may need to be repeated at a later time when the immune system is better prepared.1,2
Is there a vaccine for HIV?
At this time, there is not a vaccine that prevents HIV. However, scientists are investigating ways to develop one. Vaccines that help the immune system make more HIV-fighting proteins are currently being researched.2,8
In addition, vaccines that help strengthen the human immune system response to HIV are also being studied. These vaccines may help our bodies better fight off HIV. But further research is needed.2,8