COVID-19 vaccines for people with HIV

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Key points

  • COVID-19 vaccination is recommended for people living with HIV and they are a priority group in vaccination programmes.
  • There is no evidence that people with HIV have a higher rate of side effects after vaccination or unusual side effects.
  • COVID-19 vaccines stimulate strong antibody responses in people with HIV with higher CD4 counts, although vaccine protection may dwindle faster in people with CD4 counts below 200.
  • People with HIV are priority groups for third doses and booster doses.

Vaccines work by stimulating two arms of the immune system to provide protection. The humoral response produces antibodies, which are the first line of defence against COVID-19 and other infections. The cellular response produces T-cells that recognise and kill the virus. The T-cell response may be especially important for avoiding serious COVID-19 illness.

It’s well established that older people and immunosuppressed people have weaker responses to vaccines and these responses tend to dwindle faster than in younger people.

Studies show that people with immunosuppression caused by HIV, as indicated by a low CD4 count, have weaker responses to COVID-19 vaccines. A CD4 count below 200 appears to raise the risk of a weaker response or no response to vaccination, although this has only been established for the Pfizer and Moderna mRNA vaccines.

Several types of vaccines are in use to protect against COVID-19. All these vaccines are highly effective in preventing severe COVID-19 but somewhat less effective in preventing infection with SARS-CoV-2, the virus that causes COVID-19 illness.

The vaccines use either modified virus proteins to stimulate an immune response (the Oxford/AstraZeneca, the Johnson & Johnson and the Novavax vaccines) or viral mRNA, which instructs cells to make a non-infectious fragment of the virus so that the immune system can react to it (the Pfizer and Moderna vaccines).

The vaccines do not introduce infectious virus into the body and do not cause changes to human genes. They are broken down shortly after administration and do not stay in the body.

The Pfizer and Moderna vaccines in people with HIV

Registration studies of the Pfizer and Moderna mRNA vaccines in use in Europe and North America did not report on vaccine safety and effectiveness in the small numbers of people with HIV who took part in those trials, but subsequent studies have reported on responses to vaccination in larger groups of people with HIV.

Israeli clinicians have reported results in 143 people living with HIV who received the Pfizer vaccine. All were taking HIV treatment, 95% had an undetectable viral load and the average CD4 cell count was 700. Two doses of the vaccine were able to trigger the production of antibodies in 98% of participants, including in the small number (12) of people with CD4 cell counts below 350. Side effects were generally mild.

An Italian study compared responses to the Pfizer and Moderna vaccines after the first and second dose in 166 people with HIV and a control group of HIV-negative health careworkers. The study showed that people with CD4 counts above 500 had strong antibody responses to vaccination and these responses were just as strong as those of HIV-negative healthcare workers. People with CD4 counts between 200 and 500 had somewhat weaker responses and people with CD4 counts below 200 had much weaker antibody and T-cell responses.

Another Italian study looked at side-effects of the Moderna vaccine in 453 people with HIV. 51% reported at least one symptom after the first dose and 73% after the second dose. No serious adverse events were reported. The local and systemic reactions to vaccination were consistent with clinical trials; pain, swelling and redness at the injections site, and muscle pains, headaches, chills and fevers. Younger people were more likely to experience moderate or severe symptoms after each dose, while women and people with viral load above 50 copies/ml were more likely to experience moderate or severe symptoms after the first dose.

Glossary

vaccine

A substance that contains antigenic components from an infectious organism. By stimulating an immune response (but not disease), it protects against subsequent infection by that organism, or may direct an immune response against an established infection or cancer.

 

antibody

A protein substance (immunoglobulin) produced by the immune system in response to a foreign organism. Many diagnostic tests for HIV detect the presence of antibodies to HIV in blood.

boosting agent

Booster drugs are used to ‘boost’ the effects of protease inhibitors and some other antiretrovirals. Adding a small dose of a booster drug to an antiretroviral makes the liver break down the primary drug more slowly, which means that it stays in the body for longer times or at higher levels. Without the boosting agent, the prescribed dose of the primary drug would be ineffective.

CD4 cell count

A test that measures the number of CD4 cells in the blood, thus reflecting the state of the immune system. The CD4 cell count of a person who does not have HIV can be anything between 500 and 1500. When the CD4 count of an adult falls below 200, there is a high risk of opportunistic infections and serious illnesses.

effectiveness

How well something works (in real life conditions). See also 'efficacy'.

A US study of responses to the Pfizer or Moderna vaccines in 100 people with HIV showed that one month after the second dose, antibody responses in people with HIV depended on CD4 count. The higher the CD4 count, the stronger the antibody response. In this study, all seven participants with CD4 counts below 200 failed to generate an adequate antibody response. People who received the Moderna vaccine had stronger antibody responses than people who received the Pfizer vaccine.

Two smaller studies carried out in the United States in which most participants had high CD4 counts showed that people with HIV produced strong antibody responses to the Pfizer or Moderna vaccines after the first and second doses and these responses were similar to those in control groups of HIV-negative people. One of these studies also reported on side-effects. Almost all participants reported pain at the injection site after each vaccination. Systemic symptoms such as fatigue were common, occurring in around 60-70% of participants after each vaccination. Only one of these reactions was considered severe (headache in one participant after the second vaccination).

The Oxford/AstraZeneca vaccine in people with HIV

The Oxford/AstraZeneca vaccine studies recruited 54 people with HIV in the UK and 103 people with HIV in South Africa. Two reports have been published on the HIV-positive participants. They show that the vaccine produced the same strength of immune response in people with HIV and people without HIV. There was no difference between people with HIV and others in the common vaccine side effects of sore injection site, headache, chills, tiredness or muscle and joint pains. People in both studies had high CD4 counts (above 500) and were on antiretroviral treatment. You can read about one HIV-positive study participant’s experience here.

The Johnson & Johnson vaccine in people with HIV

The Janssen (Johnson & Johnson) vaccine study has involved the largest number of people with HIV so far: 1218 people or 2.8% of all participants. The study was conducted in the United States, South Africa and six Latin American countries. There were two cases of COVID-19 in people with HIV receiving the vaccine and four in people with HIV receiving the placebo. However, due to the small numbers of cases, this difference is not statistically significant and we cannot draw any conclusions about efficacy specifically in people with HIV.

Other vaccines in people with HIV

The Novavax vaccine is awaiting approval. Novavax recruited 201 people with HIV for one of the studies into its COVID-19 vaccine in South Africa (6% of all participants No difference in side-effects between HIV-positive and HIV-negative participants was reported. Overall efficacy of the vaccine was 49.4% (95% confidence interval 6.1-72.8), with a higher efficacy when the HIV-positive participants were excluded (60%, 95% confidence interval 19.9-80.1). The very wide confidence intervals indicate that these results should be treated with caution.

There is no information on the effectiveness of other WHO-approved vaccines (Coronavac, Covaxin or the Sinopharm VeroCells vaccine) in people with HIV.

Third vaccine doses and booster doses for people with HIV

Doctors draw a distinction between a third vaccine dose and a booster dose.

A third vaccine dose is needed if you are less likely than other people to have had a satisfactory response to the recommended two-dose course. This is regarded as part of the standard vaccination course for people at higher risk of sub-optimal vaccine responses.

In the United Kingdom, you should be offered a third dose at least eight weeks after your second dose if you have:

  • A CD4 count below 200
  • HIV-related symptoms or active tuberculosis, regardless of CD4 count
  • A detectable viral load after being on HIV treatment for at least a year
  • No current antiretroviral treatment

A booster dose protects against the gradual loss of vaccine protection that typically occurs. It is taken after a person’s first vaccine course has been completed.

A booster dose may be needed six months after the second dose by people who had a satisfactory response to the standard two-dose course. UK authorities have not yet issued guidance on booster doses for people who have completed a three-dose course.

In the UK, you should be offered a booster dose if you are living with HIV and do not meet any of the criteria for a third dose.

Even if you previously had the Oxford/AstraZeneca vaccine, the third dose or booster dose should be of the Pfizer or Moderna vaccine. (In limited circumstances, the Oxford/AstraZeneca vaccine may be given to people who have received this vaccine previously). Using different types of vaccine may improve the immune response; this is quite a common practice when giving vaccinations.

In the United States, the Centers for Disease Control and Prevention have recommended that people with advanced HIV (CD4 count below 200) or unsuppressed HIV should have an additional vaccine dose at least 28 days after their previous vaccination. If they had the Pfizer or Moderna vaccine, this will be a third dose. The first course of the Johnson & Johnson vaccine only has one dose, so recipients will have a second dose.

Concerning booster doses, people with HIV with CD4 counts above 200 can receive a booster at least six months after the second dose of the Pfizer or Moderna vaccine or two months after receiving the Johnson & Johnson vaccine.

The HIV Medicine Association has produced a briefing on US guidance regarding COVID-19 vaccines for people with HIV.

Summary

  • Vaccines against COVID-19 are highly effective in preventing serious illness. COVID-19 vaccination is recommended for people living with HIV and people with HIV are a priority group for COVID-19 vaccination.
  • COVID-19 vaccines are safe in people with HIV. There is no evidence that people with HIV have a higher rate of side-effects after vaccination or unusual side-effects. There is no evidence that any COVID-19 vaccine interacts with HIV treatment or causes HIV viral load to increase.
  • COVID-19 vaccines are effective in most people with HIV. They stimulate strong antibody responses in people with HIV with higher CD4 counts. People with lower CD4 counts (below 200) have weaker responses to vaccination and their antibody responses after vaccination may dwindle faster than those of people with higher CD4 counts.
  • People with lower CD4 counts who have already received two vaccine doses are advised to have a third dose of a COVID-19 vaccine at least eight weeks after their second dose. A third dose should improve immune responses.
  • People with any HIV-related symptoms should also have a third dose, regardless of CD4 count, as should anyone with unsuppressed viral load.
  • In the United Kingdom, a booster dose is recommended for people with HIV on treatment with CD4 counts above 200 at least six months after the second dose.
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