Pan-coronavirus vaccine (ImmunoScape/Valo Therapeutics)

MERS is a respiratory disease caused by MERS‐CoV. Multiple outbreaks have been reported, and the virus co‐circulates with SARS‐CoV‐2. The long‐term (> 6 years) cellular and humoral immune responses to MERS‐CoV and their potential cross‐reactivity to SARS‐CoV‐2 and its variants are unknown. We comprehensively investigated long‐lasting MERS‐CoV‐specific cellular and humoral immunity, and its cross‐reactivity against SARS‐CoV‐2 and its variants, in individuals recovered from MERS‐CoV infection 1–10 years prior. Two cohorts of MERS‐CoV survivors (31 unvaccinated, 38 COVID‐19 vaccinated) were assessed for MERS‐CoV IgG, memory CD4+/CD8+ T cells, and neutralizing antibodies against MERS‐CoV and SARS‐CoV‐2 variants. MERS‐CoV IgG levels and T cell responses were higher in the 1–5 vs 6–10 year postinfection groups. Vaccinated MERS‐CoV survivors had significantly elevated MERS‐CoV IgG and neutralization compared to unvaccinated. Both groups demonstrated cross‐reactive neutralization of SARS‐CoV‐2 variants. MERS‐CoV survivors vaccinated against SARS‐CoV‐2 had higher anti‐MERS IgG, cellular immunity, and neutralization than unvaccinated survivors. MERS‐CoV immune responses can persist for a decade. COVID‐19 vaccination boosted humoral and cellular immunity in MERS‐CoV survivors, suggesting the benefits of vaccination for this population. These findings have implications for pan‐coronavirus vaccine development.