Effectiveness of Pneumococcal Conjugate Vaccination Against Virus-Associated Lower Respiratory Tract Infection Among Adults: A Case-Control Study

Background Interactions of Streptococcus pneumoniae with viruses feature in the pathogenesis of numerous respiratory illnesses. Methods We undertook a case-control study among adults at Kaiser Permanente Southern California between 2015 and 2019. Case patients had diagnoses of lower respiratory tract infection (LRTI; including pneumonia or nonpneumonia LRTI diagnoses), with viral infections detected by multiplex polymerase chain reaction testing. Controls without LRTI diagnoses were matched to case patients by demographic and clinical attributes. We measured vaccine effectiveness (VE) for 13-valent (PCV13) against virus-associated LRTI by determining the adjusted odds ratio for PCV13 receipt, comparing case patients and controls. Results Primary analyses included 13 856 case patients with virus-associated LRTI and 227 887 matched controls. Receipt of PCV13 was associated with a VE of 24.9% (95% confidence interval, 18.4%-30.9%) against virus-associated pneumonia and 21.5% (10.9%-30.9%) against other (nonpneumonia) virus-associated LRTIs. We estimated VEs of 26.8% (95% confidence interval, 19.9%-33.1%) and 18.6% (9.3%-27.0%) against all virus-associated LRTI episodes diagnosed in inpatient and outpatient settings, respectively. We identified statistically significant protection against LRTI episodes associated with influenza A and B viruses, endemic human coronaviruses, parainfluenza viruses, human metapneumovirus, and enteroviruses but not respiratory syncytial virus or adenoviruses. Conclusions Among adults, PCV13 conferred moderate protection against virus-associated LRTI. The impacts of pneumococcal conjugate vaccines may be mediated, in part, by effects on polymicrobial interactions between pneumococci and respiratory viruses. Adults receiving 13-valent pneumococcal conjugate vaccine experienced 24.9% protection against virus-associated pneumonia and 21.5% protection against other virus-associated lower respiratory tract infections. Interactions with Streptococcus pneumoniaelikely contribute to the pathogenesis of viral infections in the respiratory tract.

Automated summary

PCV13 conferred moderate protection against virus-associated lower respiratory tract infections. The vaccine displayed a 24.9% effectiveness against virus-associated pneumonia and a 21.5% effectiveness against other virus-associated lower respiratory tract infections. The study also found statistically significant protection against LRTI episodes associated with influenza A and B viruses, endemic human coronaviruses, parainfluenza viruses, human metapneumovirus, and enteroviruses but not respiratory syncytial virus or adenoviruses.