Cellular immune response of COVID-19 vaccines in people living with HIV: a systematic review and meta-analysis

BACKGROUND: Available data indicate that people living with HIV (PLWH) have weaker humoral immune responses to COVID-19 vaccines compared to the general population. However, data on cellular immune responses in this group has yet to be established. METHODS: We searched the PubMed, Embase, and Cochrane Central Register of Controlled Trials databases and included studies reporting cellular immune response rates in PLWH after receiving COVID-19 vaccines. The random-effects models of proportions were performed. RESULTS: Out of the 2,598 articles identified in the initial search, 18 studies met the inclusion criteria for the meta-analysis. Among these, 4 studies assessed cellular immune responses using the interferon-γ enzyme-linked immunospot assay (ELISPOT), 12 studies utilized the interferon-γ enzyme-linked immunosorbent assay (ELISA), and 2 studies employed flow cytometric analysis. Following second dose, 63% (95% CI 47-78%) of PLWH demonstrated a cellular immune response, which increased to 88% (95% CI 79-95%) after the third dose. Overall, the pooled response rates varied across assay types, with ELISPOT assays showing 86%, ELISA 73%, and flow cytometric analysis 73% in the respective pooled estimates. The pooled cellular immune response rates were comparable for mRNA and viral vector vaccines (81% vs 83%) but were significantly lower for inactivated vaccines (49%). A pooled odds ratio (OR) of 0.65 (95% CI 0.44-0.97) revealed a lower cellular immune response in PLWH compared to healthy controls. CONCLUSION: Although COVID-19 vaccines can significantly enhance and sustain a stable cellular immune response, this response remains lower in PLWH compared to healthy controls. Greater attention should be paid to the assessment of cellular immune responses among PLWH in future vaccination studies.