Impact of obstructive sleep apnea severity and treatment on COVID-19 vaccine-induced immune responses.

BACKGROUND: Obstructive sleep apnea (OSA) is a common disorder linked to immune dysregulation and increased risk of severe coronavirus disease 2019 (COVID-19) outcomes. While vaccination is essential for preventing infection and severe disease, the impact of OSA on vaccine efficacy remains underexplored. This study examines the effects of OSA on immune responses following the third dose of the inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine (CoronaVac or BBIBP-CorV). METHODS: A total of 97 severe OSA participants with apnea-hypopnea index (AHI) >30 events/hour, and 88 healthy donors (HDs) were enrolled. Among the OSA participants, 43 individuals without symptomatic treatment before and during follow-up were designated as the untreated OSA group, while 41 participants receiving positive airway pressure (PAP) prior to the third COVID-19 vaccine dose were categorized as the treated OSA group. Full-night polysomnography (PSG) was performed to assess OSA severity. Neutralizing antibody (nAb) levels and cellular immune responses were analyzed at multiple time points following booster vaccination. RESULTS: Immune responses in untreated OSA participants were inversely associated with disease severity. Specifically, untreated OSA participants with AHI >50 events/hour exhibited significantly reduced nAb titers, antibody-secreting cell (ASC) frequencies, and circulating T follicular helper (cTfh) cells, indicating impaired immune recall responses. In contrast, PAP-treated OSA participants demonstrated improved humoral responses, notably at peak immune response stages. CONCLUSIONS: These findings highlight a severity-dependent impairment of vaccine-induced immune responses in untreated OSA participants, with evidence that PAP treatment may enhance vaccine efficacy. This study emphasizes the need to consider OSA severity and treatment when optimizing vaccination strategies for this population.