People Living With HIV and on Retroviral Therapy Have Strong Response to COVID-19 Vaccination: Canadian Study

One of the worries about COVID-19 vaccination was whether people living with HIV would respond as well to the vaccine as people without HIV.

But so far, most of the evidence has allayed those concerns, including results reported by a group of Canadian researchers.

Zabrina Brumme

In fact, corresponding author Zabrina L. Brumme, Ph.D., a professor at Simon Fraser University in British Columbia, Canada, and her colleagues reported that people living with HIV had the same or an even stronger antibody response to a third shot of a vaccine and that was especially so for those who were vaccinated with the Moderna vaccine.

Brumme and her coinvestigators reported results as a preprint in medRxiv in March.

The study was based on a comparison between 99 people living with HIV with 152 people without HIV.

Brumme noted, though ,that the people living with HIV and control groups were not perfectly matched in terms of age, sex and other characteristics, but the study was large enough so that the research team could account for these differences in the analyses.

“This study was important to do because we knew that COVID-19 vaccination was particularly important for people living with HIV, as previous research had suggested that this group may be at increased risk of severe COVID-19,” Brumme said. “But, at the time, there was very little data on COVID-19 vaccine immune responses in this population.”

Furthermore, Brumme noted, impaired responses to COVID-19 vaccination had been seen in certain immunocompromised groups. Also, there was previous evidence from other types of vaccinations — flu shots, for example — that the immune system response to vaccination might be less robust in people living with HIV, even those who antiretroviral therapy.

Eighty-two of the people living with HIV in the study received two doses of mRNA vaccine, eight received the two doses of the Oxford-AstraZeneca vaccine — which has not been approved by the FDA — and eight were vaccinated with one dose of the Oxford-AstraZeneca vaccine and one of two mRNA vaccines. Of the 80 people who received a third shot, 23 were boosted with the Pfizer vaccine and 56 with the Moderna one.

The research team measured antibodies against the SARS-CoV-2 spike protein receptor-binding domain, ACE2 displacement and viral neutralization against wild-type and omicron strains up to six months following two-dose vaccination, and one month following the third dose in the entire

“Though humoral responses naturally decline following two-dose vaccination, we found no evidence of lower antibody concentrations nor faster rates of antibody decline in PLWH (people living with HIV) compared to controls after accounting for sociodemographic, health and vaccine-related factors,” the research team noted. “We also found no evidence of poorer viral neutralization in PLWH after two doses, nor evidence that a low nadir CD4+ T-cell count compromised responses.”

The researchers discovered no difference in the rate of decline of antibodies after the second dose between people with HIV and the control group, plus after a third dose, antibody levels had risen above the concentrations observed one month after the second dose and in almost half of cases, concentrations were above the upper limit of the antibody assay.

“The main takeaway was that people with HIV, who have well-controlled viral loads on therapy and preserved CD4+ T-cell counts, mount strong and functional antibody responses to two and three-dose COVID-19 vaccination, including to the omicron variant that is now dominant,” Brumme said. “In fact, after controlling for sociodemographic, health- and vaccine-related variables, the vaccine responses observed in people with HIV were comparable to people without HIV.”

Those who had received two doses of the Oxford Astra-Zeneca vaccine, older people and people with multiple health conditions were found to more likely experience lower antibody levels as well.

The researchers concluded that PLWH receiving suppressive antiretroviral therapy mount strong antibody responses after two- and three-dose COVID-19 vaccination, thought the results underscore the immune benefits of third doses in light of omicron.

The findings suggest that having a previous history of low CD4 count will not compromise vaccine responses. Additionally, those with well-treated HIV have just as good, if not better, responses to a third vaccine dose than people without HIV.