Healthcare workers are at increased risk of exposure to respiratory pathogens including Streptococcus pneumoniae (pneumococcus). While little asymptomatic carriage has been reported in young-to-middle-aged adults, this may be due to non-sensitive diagnostic methods, say Waghela, et al. (2025) who sought to investigate the rates of pneumococcal carriage in a large cohort of healthcare workers, using saliva as a respiratory specimen.

The researchers evaluated pneumococcal carriage in convenience samples of saliva, self-collected from asymptomatic healthcare workers who were testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from March 30 to June 11, 2020. DNA extracted from the culture-enriched saliva was later tested using quantitative polymerase chain reaction for piaB, lytA, and serotype. Saliva samples were considered positive for pneumococcus when the piaB cycle threshold value was <40.

Study participants were 22–74 years old (mean age, 38.5 years), 75% female, 75% white, and with occupations including registered nurses (48%), medical doctors (23%), and patient care assistants (5%). Overall, 138 of 1241 samples (11%) from 86 of 392 individuals (21%) tested piaB positive at some point during the 4-month study period, with 28 (33%) colonized individuals positive at multiple time points. Carriers reflected the overall study population. No significant demographic characteristics were associated with detection of pneumococcus. Colonized individuals primarily carried serotypes 19F (25.6%) and 3 (12.8%).

During a period of mandatory masking, the researchers identified a cumulative pneumococcal carriage prevalence of 21% among healthcare workers. This study highlights that healthcare workers may act as unrecognized reservoirs of pneumococcus in the population. Despite long-standing pediatric immunization programs, vaccine-targeted serotypes continue to be prevalent among the adult population.

Source: Waghela P, et al. Detection of Pneumococcal Carriage in Asymptomatic Healthcare Workers. Open Forum Infectious Diseases, Volume 12, Issue 2, February 2025, ofaf008, https://doi.org/10.1093/ofid/ofaf008