Prior research has pointed to the protective effects of 13-valent pneumococcal conjugate vaccine (PCV13) in viral and bacterial respiratory diseases. In a retrospective study published in The Journal of Infectious Diseases, PCV13 also showed protective effects against SARS-CoV-2 infections.
The study authors measured associations between PCV13 and COVID-19 outcomes, with or without 23-valent pneumococcal polysaccharide vaccine (PPSV23), using information from electronic health records of adults aged 65 and older. Between March 1 and July 22, 2020, there were 3677 COVID-19 diagnoses among 531,033 adults in the study cohort, with 1075 hospitalizations and 334 fatalities. PCV13 was given to 451,068 participants aged 65 or older and had comorbidities associated with pneumonia and COVID-19. These participants also did not receive PCV13.
The estimated adjusted hazard ratios (aHRs) for PCV13 recipients with COVID-19 diagnosis, hospitalization, and mortality were 0.65 (95% CI, 0.59%-0.72%), 0.68 (95% CI, 0.57%-0.83%), and 0.68 (95% CI, 0.49%-0.95%), respectively. Prior PPSV23 was not associated with a significant protective effect against these 3 outcomes. The association between PCV13 and COVID-19 lessened temporarily within 90 days of receiving antibiotics for pneumococcal viruses. From 90 to 365 days after antibiotics exposure, the adjusted odds ratio (aOR) for COVID-19 diagnosis associated with PCV13 vaccination was 0.65 (95% CI, 0.50%-0.84%).
Citing earlier research that bacterial carriage may enhance viral replication and pathogenicity in respiratory diseases, and that PCV13 pneumococcal serotype carriage is lower in adults in settings with well-established vaccination programs, the study authors suggested that lower rates of pediatric PCV13 vaccination due to the COVID-19 pandemic could exacerbate the effect of PCV13 serotypes on respiratory viruses, such as SARS-CoV-2.
One limitation of the study was associating zoster vaccination with COVID-19 outcomes as an indicator of bias, since there is insufficient data on whether zoster has non-specific effects against COVID-19.
“Improved understanding of viral-bacterial interactions during SARS-CoV-2 infection remains necessary to validate the mechanistic basis for our findings,” study authors noted. “However, our results are in agreement with other data suggesting the pathogenicity of respiratory viruses may be modified by bacterial carriage.”
Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.
Lewnard JA, Bruxvoort KJ, Fischer H, et al. Prevention of COVID-19 among older adults receiving pneumococcal conjugate vaccine suggests interactions between Streptococcus pneumoniae and SARS-CoV-2 in the respiratory tract. J Infect Dis. Published online March 9, 2021. doi:10.1093/infdis/jiab128