Burden of Lower Respiratory Tract Infections Preventable by Adult Immunization With 15- and 20-Valent Pneumococcal Conjugate Vaccines in the United States.

ABSTRACT

BACKGROUND: Updated recommendations of the US Advisory Committee on Immunization Practices indicate that all adults aged ≥65 years and adults aged <65 years with comorbid conditions should receive 15- and 20-valent pneumococcal conjugate vaccines (PCV15/20). We aimed to assess the potential impact of these recommendations on the burden of lower respiratory tract infections (LRTIs) among adults. METHODS: We estimated the incidence of LRTI cases and associated hospital admissions among enrollees of Kaiser Permanente Southern California from 2016 through 2019. We used a counterfactual inference framework to estimate excess LRTI-associated risk of death up to 180 days after diagnosis. We used prior estimates of PCV13 effectiveness against LRTI to model potential direct effects of PCV15/20 by age group and risk status. RESULTS: Use of PCV15 and PCV20, respectively, could prevent 89.3 (95% confidence interval, 41.3-131.8) and 108.6 (50.4-159.1) medically attended LRTI cases; 21.9 (10.1-32.0) and 26.6 (12.4-38.7) hospitalized LRTI cases; and 7.1 (3.3-10.5) and 8.7 (4.0-12.7) excess LRTI-associated deaths, each per 10 000 person-years. Among at-risk adults aged <65 years, use of PCV15 and PCV20 could prevent 85.7 (39.6-131.5) and 102.7 (47.8-156.7) medically attended LRTI cases per 10 000 person-years; 5.1 (2.4-8.6) and 6.2 (2.8-10.2) LRTI hospitalizations per 10 000 person-years, and 0.9 (0.4-1.4) and 1.1 (0.5-1.7) excess LRTI-associated deaths per 10 000 person-years. CONCLUSIONS: Our findings suggest recent recommendations, including PCV15/20 within adult pneumococcal vaccine series, may substantially reduce LRTI burden.