The annual incidence of radiologically confirmed community-acquired pneumonia among hospitalized adults in Germany reached 490 per 100,000 adults between July 2021 and June 2023, with rates 11-fold higher in individuals aged 65 years and older vs those aged 18 to 64 years, according to a prospective multicenter surveillance study.
In the population-based study, investigators conducted active surveillance at three hospitals in Thuringia from January 1, 2021, through June 30, 2023. All of the admitted adults with suspected pneumonia were screened using clinical criteria, imaging, and microbiology. Cases of radiologically confirmed community-acquired pneumonia (RAD-CAP) with symptom onset within 48 hours of admission were included in incidence analyses.
Among 4,705 patients meeting eligibility criteria, 1,577 were enrolled. Among the enrolled patients, 1,479 had RAD-CAP. Surveillance captured 90% of admitted cases at the primary site. The enrolled patients had a median age of 70 years; 12.8% required intensive care, 7.7% required mechanical ventilation, and 7.2% died during hospitalization.
Pathogen testing showed SARS-CoV-2 in 36.5%, Streptococcus pneumoniae in 9.1%, respiratory syncytial virus (RSV) in 3.7%, and influenza A or B in 1.8% of RAD-CAP cases. In 2022 and 2023, S pneumoniae, RSV, and influenza accounted for 11.6%, 5.6%, and 4% of cases, respectively, an increase compared with early 2021.
The denominator-adjusted annual incidence of all-cause RAD-CAP between the 2021 and 2022 and 2022 and 2023 epidemiologic years was 490 per 100,000 adults overall, with incidence estimates based on July to June surveillance periods and excluding January through June 2021. The rates ranged from 117 per 100,000 individuals aged 18 to 64 years to 1,538 per 100,000 individuals aged 65 years and older. Among those aged 65 years and older, the incidence increased from 1,113 per 100,000 in 2021 to 1,692 per 100,000 in 2022 and 2023, a 52% increase. In contrast, the rates declined among younger adults.
Pathogen-specific incidence in 2022 and 2023 reached 97 per 100,000 for SARS-CoV-2, 60 per 100,000 for pneumococcus, 30 per 100,000 for RSV, and 19 per 100,000 for influenza. Compared with individuals aged 18 to 64 years, the incidence among those aged 65 years and older was 12 times higher for pneumococcus and 22 times higher for RSV.
Pneumococcal serotypes included in the 20-valent pneumococcal conjugate vaccine accounted for 10% of all RAD-CAP cases and 84% of pneumococcal cases in 2022 and 2023.
Limitations included incomplete case capture at two sites during the COVID-19 pandemic, lower enrollment among older and more severely ill patients, and limited sensitivity of nasopharyngeal polymerase chain reaction testing for RSV and urinary antigen detection for S pneumoniae, which likely underestimated the pathogen-specific burden.
“To our knowledge, this is the first prospective, multicenter, population-based surveillance study on the epidemiology of CAP in Germany at the time of a receding of the COVID-19 pandemic and the resurgence of other pneumonia pathogens,” wrote lead study author Christian Theilacker, of Pfizer Vaccines at Pfizer, and colleagues.
Pfizer funded and sponsored the study. Co–study authors Christian Theilacker, Claudia Schwarz, Christof von Eiff, Ralf-Dirk Wolf, Jeffrey Vietri, Elizabeth Wang, and Kaijie Pan are employed full time by Pfizer Vaccines and may own shares or stock options in the company. Additionally, co–study author Bradford D. Gessner was employed by Pfizer during the study’s conduct and analysis and may also hold shares or stock options. The study authors reported no other competing interests.
Source: BMJ Open
