A CITF-funded study, published in preprint, and not yet peer-reviewed, from Mark Brockman and Zabrina Brumme (Simon Fraser University and BC Centre for Excellence in HIV/AIDS), along with Drs. Aslam Anis and Marc Romney (University of British Columbia) showed that the antibody responses induced by a third dose of COVID-19 vaccine were as durable in people living with HIV (PLWH) receiving antiretroviral therapy (ART) as in individuals without HIV.
Key findings:
- In PLWH receiving suppressive antiretroviral therapy, third doses of vaccine boosted antibody levels above those reached after the initial two-dose primary series, and were comparable to responses seen in control participants without HIV.
- In both groups however, the antibody responses to the original Omicron-BA.1 variant remained lower than responses against the ancestral strain, while responses to the recently circulating Omicron-BA.5 were even lower.
- Among individuals who never had COVID-19, antibody levels declined at similar rates in PLWH compared to controls without HIV. In addition, the decline was not accelerated for the Omicron sub-variant (BA.1) compared to the ancestral strain.
- Viral neutralization also declined rapidly. Among individuals who never had COVID-19, by six months after the third dose, Omicron BA.1-specific neutralization was undetectable in more than 80% of COVID-naïve PLWH and in more than 90% of COVID-naïve controls without HIV.
- A recent infection with SARS-CoV-2 boosted the level and function of antibodies above those induced by three vaccine doses alone, in both PLWH and controls. However, resulting hybrid immunity remained weaker against the Omicron BA.5 sub-variant than against the Omicron BA.1 sub-variant.
Researchers suggest that, given the comparable durability of vaccine-induced antibody responses, all individuals who have not yet experienced a SARS-CoV-2 infection will benefit from a fourth booster dose within six months of their third dose.