Prevention of COVID-19 among older adults receiving pneumococcal conjugate vaccine suggests interactions between Streptococcus pneumoniae and SARS-CoV-2 in the respiratory tract

Introduction While secondary pneumococcal pneumonia occurs less commonly after COVID-19 than after other viral infections, it remains unclear whether other interactions occur between SARS-CoV-2 and Streptococcus pneumoniae Methods We probed potential interactions between these pathogens among adults aged ≥65y by measuring associations of COVID-19 outcomes with pneumococcal vaccination (13-valent conjugate and 23-valent polysaccharide;PCV13, PPSV23) We estimated adjusted hazard ratios (aHRs) using Cox proportional hazards models with doubly-robust inverse-propensity weighting We assessed effect modification by antibiotic exposure to further test the biologic plausibility of a causal role for pneumococci Results Among 531,033 adults, there were 3,677 COVID-19 diagnoses, leading to 1,075 hospitalizations and 334 fatalities, between 1 March-22 July, 2020 Estimated aHRs for COVID-19 diagnosis, hospitalization, and mortality associated with prior PCV13 receipt were 0 65 (95% confidence interval: 0 59-0 72), 0 68 (0 57-0 83), and 0 68 (0 49-0 95), respectively Prior PPSV23 receipt was not associated with protection against the three outcomes COVID-19 diagnosis was not associated with prior PCV13 within 90 days following antibiotic receipt, whereas aHR estimates were 0 65 (0 50-0 84) and 0 62 (0 56-0 70) during risk periods 91-365d and >365d following antibiotic receipt, respectively Discussion Reduced risk of COVID-19 among PCV13 recipients, transiently attenuated by antibiotic exposure, suggests pneumococci may interact with SARS-CoV-2 COVID-19, SARS-CoV-2, Streptococcus pneumoniae, pneumococcal conjugate vaccine, older adults, polymicrobial infection