Antiretroviral Therapy Distorts COVID-19 Neutralization Assay Results and Impacts Vaccine Efficacy
1. Attenuated Immune Defense and Hidden Laboratory Pitfalls
People living with HIV (PLWH) often exhibit weaker immune responses to COVID-19 mRNA vaccination compared with HIV-negative individuals. However, a subtle experimental confounder was identified: residual antiretroviral therapy (ART) compounds in patient plasma can produce apparent “false-positive” neutralization results in laboratory virus-neutralization assays, making the vaccine appear more effective than it truly is.
2. Treatment-Induced Assay Artifacts and Altered Immune Profiles
The investigators demonstrated that serum containing integrase strand transfer inhibitors (INSTIs) yields abnormally high pseudovirus neutralization activity. They also found that PLWH display altered antibody subclass distributions (e.g., IgG1, IgA) and reduced antibody-dependent cellular phagocytosis (ADCP) compared with controls. These immunologic shifts correlated closely with the degree of T-cell deficiency in the patients.
3. Implications and Future Directions
Future assessments of vaccine efficacy in PLWH should employ assay platforms that are not susceptible to interference from ART components. Correcting these methodological errors will generate accurate data, enabling the design of personalized mRNA vaccination strategies tailored to immunocompromised patients.
People living with HIV infection (PLWH) often have attenuated responses to infections and vaccination. This study aimed to better understand how HIV-associated inflammation and chronic T-cell activation influenced the immune responses to mRNA vaccination or neutralization assay analyses. PLWH on ART or healthy donor controls were analyzed using systems serology and viral T-cell phenotyping to Spike or HIV-1 Gag peptide stimulation after primary mRNA COVID-19 vaccination. Neutralization assays using a lentiviral pseudovirus construct were compromised by the presence of integrase strand transfer inhibitor (INSTI) drugs in plasma from HIV + subjects taking certain ART. This combination of lentiviral pseudovirus reporter assays and INSTIs led to false positive neutralization results. Spike-specific IgG1, IgG3, IgA1, IgA2, and antibody-dependent cellular phagocytosis (ADCP) were altered post-vaccination in PLWH compared to controls. Network and multivariate analyses revealed post-vaccination outcomes were strongly correlated to CD4 immunodeficiency and Gag-specific T-cells, including effector CD8 T-cells and Th1 CD4 T-cells. Given the growing use of pseudovirus neutralization assays for serological evaluation and mRNA technology in novel vaccines that could be recommended for PLWH Pseudovirus neutralization assays need to be carefully selected to prevent ART drugs in patient samples from impacting results. Spike-specific antibody and CD4 T-cell phenotypes are influenced by both CD4 immunodeficiency and Gag-specific T-cell effector populations. This work has clinical relevance beyond COVID, with future considerations of pseudovirus assay evaluations and mRNA vaccine design for chronically infected hosts.
It prevents situations where vaccine efficacy is mistakenly perceived as higher due to drug interference, thereby exposing patients to risk. Accurate validation enables the development of truly needed booster schedules and personalized protection strategies for people living with HIV.