TOPLINE

Inpatient all-cause pneumonia rates among US adults decreased following the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13) in children. However, significant disparities persisted during 2017-2019, with Black adults, those with at-risk or high-risk conditions, and individuals with annual household income (HHI) below $100,000 experiencing disproportionately higher rates of hospitalized pneumonia.

METHODOLOGY

• Researchers conducted a retrospective observational study using data from Optum's de-identified database from 2007-2019 to evaluate trends in rates of inpatient all-cause pneumonia from 2008 to 2019, spanning the period before and after introduction of pediatric PCV13.
• They analyzed 38.7 million US adults aged ≥18 years with at least one year of continuous healthcare coverage. 
• Adults were stratified by age (18-49, 50-64, 65-74, ≥75 years), race (Asian, Black, Hispanic, White), comorbidity profile (low-risk, at-risk, high-risk based on chronic medical conditions or immunocompromising conditions), and annual HHI (<$50,000, $50,000-$99,999, ≥$100,000). Overall, 55% were aged 18-49 years, 23% were aged 50-64 years, 14% were aged 65-74, and 8% were aged ≥75 years; 51% were women.
• Researchers estimated rates of inpatient all-cause pneumonia per 100,000 person-years and incidence rate ratios (IRR) for Pre-PCV13 (2008-2009), Peri-PCV13 (2010-2012), Post-PCV13#1 (2013-2016), and Post-PCV13#2 (2017-2019) periods.

TAKEAWAY

• Rates of inpatient all-cause pneumonia decreased across all age groups from the Pre-PCV13 to Post-PCV13#2 period. For instance, among adults aged 18-49 years, rates fell from 72.9 to 38.2 per 100,000 person-years (IRR, 0.52); among adults aged ≥75 years, rates fell from 1,621.8 to 1,326.0 (IRR, 0.82). 
• Across all age groups, inpatient all-cause pneumonia rates were highest in Black adults, adults with at-risk/high-risk conditions, and adults with household income less than $50,000. In adults aged 18 to 49 years, Post-PCV13#2 IRRs vs Pre-PCV13 ranged from 0.46 to 0.66 across race, comorbidity, and income subgroups, while among adults aged ≥50 years, rates declined in about two-thirds of subgroups but were stable or increased in others.
• During Post-PCV13#2, Black adults aged 18-49 years had nearly twice the pneumonia rate of White adults (IRR, 1.90), with the gap narrowing but persisting through ages 50-74 years. Adults with at-risk or high-risk comorbidity profiles had markedly higher rates than low-risk adults across all age groups, with IRRs ranging from 11.33 for those aged 18-49 years to 2.43 for those aged ≥75 years.
• Lower household income remained a persistent risk factor for inpatient all-cause pneumonia, with IRRs for low-income and middle-income vs high-income households ranging from 1.32 to 5.14 and from 1.12 to 2.18, respectively; disparities were most pronounced among adults aged 50-64 years.

IN PRACTICE

“Despite the reduction in cases, though, disparities in the burden of disease remain among certain population subgroups, including Black persons, those with at-risk/high-risk conditions, and persons with HHI <$100,000. Our findings highlight the importance of continually assessing and improving strategies to address these disparities," the authors concluded.

SOURCE

The study was led by Mark H. Rozenbaum, PhD, MBA, Pfizer Inc. in Capelle A/d Ijssel, Netherlands. It was published online  on August 24, 2026, in Open Forum Infectious Diseases.

LIMITATIONS

The study population may not be representative of all US adults, as it excluded uninsured individuals and those with Medicaid or fee-for-service Medicare coverage. Classification of comorbidity profiles and pneumonia episodes using claims data may have resulted in some misclassification bias, and race and HHI proxies were based on a mix of individual-level and ecological-level data that have not been validated against a gold standard.

DISCLOSURES

The study was supported by Pfizer Inc. Five authors were employees of Pfizer Inc. and held Pfizer stock, while some others were employees of Avalere Health, which received funding from Pfizer for this work. Full author disclosures are reported in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.