Evaluating the association between routine pneumococcal vaccination and COVID-19 severity among older adults in the United States: A case control study

The relationship between infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and disease caused by Streptococcus pneumoniae remains uncertain. This case-control study investigated the association between pneumococcal vaccination and the progression to severe outcomes among COVID-19 patients aged 65 and older in the United States. We identified COVID-19 patients aged 65 and older with severe outcomes (cases) and those with non-severe or less severe outcomes (controls) from Medicare data from April 2020 to December 2021. Logistic regression models were employed to evaluate the association between prior receipt of pneumococcal vaccination (13-valent conjugate vaccine [PCV13] and/or 23-valent pneumococcal polysaccharide vaccine [PPSV23]) and severe COVID-19 outcomes. A total of 28,124 COVID-19 patients exhibited severe respiratory symptoms or were admitted to the intensive care unit (ICU). The odds of progression from non-severe symptoms to severe respiratory symptoms were modestly lower among COVID-19 patients with PCV13 receipt (odds ratio (OR): 0.91 (95 % confidence interval [CI], 0.88, 0.93), compared to those without PCV13. The odds of requiring ICU admission were lower among COVID-19 patients with severe respiratory outcomes who received PCV13, compared to those who did not (OR: 0.92; 95 % CI, 0.88, 0.97). The magnitude of the associations was similar when evaluating the associations between the receipt of influenza or zoster vaccinations and the severity of COVID-19 outcomes. Finally, there was no association between receiving PPSV23 more than five years ago and COVID-19 severity. Overall, our findings indicated modest to no association between pneumococcal vaccination and severe COVID-19 outcomes among older adults with COVID-19.