- COVID-19 vaccines are highly effective at preventing serious disease and hospitalization in HIV-negative people
- Reports of the immunological effects of these vaccines on HIV-positive people are scarce
- A study with 54 HIV-positive people found that the AstraZeneca vaccine is safe and promising
Large pivotal clinical trials of COVID-19 vaccines have been done with tens of thousands of HIV-negative people. However, little information about the effect of these vaccines on HIV-positive people is available.
A team of researchers in London, England, along with other researchers at the University of Oxford have cooperated and carried out a study with 54 HIV-positive adults. The participants received two doses of the AstraZeneca COVID-19 vaccine.
Prior to entering the study, all participants were taking HIV treatment (ART) and had an undetectable level of HIV in their blood (viral load) and relatively high CD4+ cell counts. Participants were monitored for almost two months. Data from a group of 50 HIV-negative adults who were also vaccinated with the AstraZeneca vaccine were used for purposes of comparison.
The researchers found that side effects after vaccination were similar in both groups of participants. Furthermore, no serious side effects were reported.
Levels of antibodies against SARS-CoV-2 rose after vaccination and were detectable to the end of the study. The ability of T-cells to respond to SARS-CoV-2 also increased after vaccination and were detectable to the end of the study. There were no significant differences in antibody levels or T-cell responses between HIV-positive and HIV-negative participants arising from vaccination.
This small study has found that the AstraZeneca vaccine is safe and causes the immune system to develop and maintain antibodies and T-cells that can attack SARS-CoV-2 in HIV-positive people who are healthy and on ART.
Study details
Participants were part of a large phase II/III clinical trial of the AstraZeneca COVID-19 vaccine. They were enrolled in November 2020 and received two doses of the vaccine four to six weeks apart.
The average profile of the HIV-positive people (all were men) at the start of the study was as follows:
- age – 43 years
- major ethno-racial groups – 85% white; 7% mixed, 4% Asian
- CD4+ count – 700 cells/mm3
- HIV viral load – less than 50 copies/mL
For purposes of comparison, the researchers used data from 50 HIV-negative adults (26 men and 24 women) with an average age of about 39.
Results
There were no severe side effects; most were of mild or moderate intensity in participants in both groups.
Common systemic side effects after the first dose of vaccination among HIV-positive people were as follows:
- fatigue – 49%
- headache – 49%
- muscle aches – 36%
- feeling generally unwell – 34%
- chills – 23%
- joint pain – 9%
HIV-negative people reported a similar range and intensity of side effects after the first and second doses. However, among HIV-positive people, side effects seemed to be lessened after their second dose.
Vaccines – training the immune system
Vaccines train the immune system to recognize and identify an invading germ—in this case, the virus called SARS-CoV-2. There are generally two broad responses to vaccination:
- antibodies are created that help the immune system identify SARS-CoV-2 and, in some cases, prevent SARS-CoV-2 from causing infection
- certain cells of the immune system—T-cells and natural killer cells—learn to recognize and attack SARS-CoV-2-infected cells
Focus on antibodies
Analyses of blood samples from HIV-positive participants found that levels of antibodies against SARS-CoV-2 peaked 14 days after the second dose of the vaccine. After this time, antibody levels were maintained over the course of the study. There were no significant differences in antibody levels between HIV-positive and HIV-negative people.
Among HIV-positive people, CD4+ cell counts ranged from about 300 cells/mm3 to 1,100 cells/mm3 during the study. There was no impact of the vaccine on CD4+ cell counts. Antibody responses after vaccination were similar regardless of a person’s CD4+ cell count.
In a subset of 15 HIV-positive people, researchers analyzed the ability of the antibodies generated by vaccination to stop SARS-CoV-2 from infecting cells. After vaccination, levels of antibodies that could block SARS-CoV-2 infection were detected in 13 out of 15 people and increased over the course of the study.
Focus on T-cells
The researchers used different techniques to assess the ability of T-cells to detect and respond to SARS-CoV-2. They found that antiviral responses peaked between days 14 and 28—after the first dose of the vaccine. After this time, the ability of T-cells to respond to the virus decreased but continued to be detectable over the course of the study. There were no significant differences in T-cell responses between HIV-positive and HIV-negative people.
Excess immune activation
People with chronic HIV infection develop persistent immunological activation. The levels of immunological activation are higher in HIV-positive people than in healthy HIV-negative people. Initiating ART and achieving and maintaining an undetectable level of HIV in the blood greatly reduces but does not normalize excess immunological activation. Many HIV researchers think that excess immune activation fuels inflammation, which likely contributes to slowly degrading organ-systems in HIV-positive people.
Therefore, it is important to assess interventions such as COVID-19 vaccines for any impact on the functioning of the immune system. The good news is that the AstraZeneca COVID-19 vaccine did not increase the activation of the immune system. The vaccine was also effective regardless of pre-vaccination levels of inflammation in HIV-positive people.
Bear in mind
Although the present study was small, it found that the AstraZeneca COVID-19 vaccine was generally safe and caused the immune system of HIV-positive people to respond appropriately. The British researchers performed extensive immunological analyses. Their immunological investigations should stimulate other researchers to do the same with other COVID-19 vaccines in HIV-positive people.
The present study was not designed to assess the disease-preventing effects of the vaccine. However, the British researchers noted the following: The immune responses of HIV-positive people arising from vaccination were similar to those reported in larger studies of HIV-negative people where vaccines did reduce the risk of SARS-CoV-2 infection and COVID-19. The British researchers are therefore encouraged by the present small study’s findings.
For the future
Participants in the present study were healthy and well and had CD4+ counts of 350 cells/mm3 and higher. Some HIV-positive people can have lower levels of CD4+ cells even with good adherence to ART and an undetectable viral load. Studies should be done to explore the effect of COVID-19 vaccines on people with lower CD4+ cell counts and/or who have other underlying issues such as the following:
- cancer
- organ transplantation
- taking powerful anti-inflammatory drugs for rheumatoid arthritis, intestinal inflammation (such as Crohn’s disease, colitis), psoriasis and other conditions
The British researchers plan to continue to collect and assess data at six and 12 months after vaccination in this group of people. Note that the data we reported on from the UK have been submitted to the journal Lancet HIV but have not yet been peer-reviewed. Therefore, this study’s findings should be considered promising but preliminary.
—Sean R. Hosein
Resources
Encouraging results from the Pfizer-BioNTech COVID-19 vaccine in HIV-positive people – CATIE News
New York State assesses the impact of COVID-19 on HIV-positive people – CATIE News
HIV and COVID-19 – TreatmentUpdate 238
Frequently asked questions about vaccines for the prevention of COVID-19 – CATIE
COVID-19 Vaccines – National Advisory Committee on Immunizations
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