Association of Pneumococcal Conjugate Vaccine Use With Hospitalized Pneumonia in Medicare Beneficiaries 65 Years or Older With and Without Medical Conditions, 2014 to 2017.

Importance
The association of 13-valent pneumococcal conjugate vaccine (PCV13) use with pneumonia hospitalization in older adults, especially those with underlying medical conditions, is not well described.


Objective
To evaluate the association of PCV13 use with pneumonia, non-health care-associated (non-HA) pneumonia, and lobar pneumonia (LP) hospitalization among US Medicare beneficiaries 65 years or older.


Design, Setting, and Participants
This cohort study with time-varying exposure assignment analyzed claims data from US Medicare beneficiaries 65 years or older enrolled in Parts A/B with a residence in the 50 US states or the District of Columbia by September 1, 2014. New Medicare Parts A/B beneficiaries within 6 months after their 65th birthday were continuously included in the cohort after September 1, 2014, and followed through December 31, 2017. Participants were censored if they died, changed enrollment status, or developed a study outcome. Most of the analyses were conducted from 2018 to 2019, and additional analyses were performed from 2021 to 2022.


Exposures
Use of PCV13 vaccination 14 days or more before pneumonia hospitalization.


Main Outcomes and Measures
Discrete-time survival models were used to estimate the incidence rate ratio (IRR) and number of pneumonia hospitalizations averted through PCV13 use. The adjusted IRR for the association of PCV13 vaccination with pneumonia hospitalization was used to estimate vaccine effectiveness (VE).


Results
At the end of follow-up (December 2017), 24 121 625 beneficiaries (13 593 975 women [56.4%]; 418 005 [1.7%] Asian, 1 750 807 [4.8%] Black, 338 044 [1.4%] Hispanic, 111 508 [0.5%] Native American, and 20 700 948 [85.8%] White individuals) were in the cohort; 4 936 185 (20.5%) had received PCV13 only, and 10 646 220 (79.5%) had not received any pneumococcal vaccines. More than half of the beneficiaries in the cohort were younger than 75 years, White, and had either immunocompromising or chronic medical conditions. Coverage with PCV13 increased from 0.8% (September 2014) to 41.5% (December 2017). The VE for PCV13 was estimated at 6.7% (95% CI, 5.9%-7.5%) for pneumonia, 4.7% (95% CI, 3.9%-5.6%) for non-HA pneumonia, and 5.8% (95% CI, 2.6%-8.9%) for LP. From September 2014 through December 2017, an estimated 35 127 pneumonia (95% CI, 33 011-37 270), 24 643 non-HA pneumonia (95% CI, 22 761-26 552), and 1294 LP (95% CI, 797-1819) hospitalizations were averted through PCV13 use.


Conclusions and Relevance
The study results suggest that PCV13 use was associated with reduced pneumonia hospitalization among Medicare beneficiaries 65 years or older, many of whom had underlying medical conditions. Increased PCV13 coverage and use of recently approved higher-valent pneumococcal conjugate vaccines may avert additional pneumonia hospitalizations in adults.