A study of healthcare workers at a Connecticut hospital during the early months of the COVID-19 pandemic found that more than one in five were positive for pneumococcal carriage, researchers reported yesterday in Open Forum Infectious Diseases.
The study, conducted by researchers at Yale University, evaluated carriage of Streptococcus pneumoniae in a convenience sample of medical staff at Yale New Haven Hospital who had enrolled from March 30 to June 11, 2020, in a study that was initially designed to actively monitor asymptomatic healthcare workers for SARS-CoV-2 infection. Using the stored, self-collected saliva samples from that study, the researchers extracted DNA and tested it for the presence of pneumococcal-specific genes piaB and lytA. Samples were considered positive when the piaB cycle threshold (Ct) value was less than 40.
Of the 525 participants who enrolled in the study, samples from 392 participants (mean age, 38.7 years; 74% female; 73% white) were selected to test for pneumococcus. Overall, 138 (11%) of 1,241 samples from 86 (21%) of 392 individuals tested piaB-positive during the 4-month study period, with 28 (33%) of 86 colonized individuals positive at multiple time points. Positive individuals reflected the overall study population. Analysis of pneumococcal serotypes found colonized participants primarily carried serotypes 19F (25.6%) and 3 (12.8%), both of which are targeted by the PCV13 vaccine, which covers 13 pneumococcal strains.
'Unrecognized reservoir' of pneumococcus
The study authors note that the 21% prevalence of pneumococcal carriage observed in the study was at a time when strict non-pharmaceutical interventions for COVID-19 (such as masking) were in place and largely adhered to in healthcare settings, and global incidence of invasive pneumococcal diseases had declined. They suggest the rate could be higher post-pandemic, now that those mitigation measures are no longer in place and typical annual circulation of respiratory pathogens has returned.
"This study highlights that healthcare workers may act as unrecognized reservoirs of pneumococcus in the population," they concluded. "Despite longstanding pediatric immunization programs, vaccine-targeted serotypes continue to be prevalent among the adult population."