Persistence of pneumococcal carriage among older adults in the community despite COVID-19 mitigation measures

ABSTRACT

BackgroundReported rates of invasive pneumococcal disease were markedly lower than normal during the 2020/2021 winter in the Northern Hemisphere, the first year after the start of the COVID-19 pandemic. However, little is known about rates of carriage of pneumococcus among adults during this period. MethodsBetween October 2020-August 2021, couples living in the Greater New Haven Area were enrolled if both individuals were aged 60 years and above and did not have any individuals under the age of 60 years living in the household. Saliva samples and questionnaires regarding social activities and contacts and medical history were obtained every 2 weeks for a period of 10 weeks. Following culture-enrichment, extracted DNA was tested using qPCR for pneumococcus-specific sequences piaB and lytA. Individuals were considered positive for pneumococcal carriage when Ct-values for piaB were less than 40. ResultsWe collected 567 saliva samples from 95 individuals aged 60 years and above (47 household pairs and one singleton). Of those, 7.1% of samples tested positive for pneumococcus by either piaB only (n=6) or both piaB and lytA (n=34), representing 22/95 (23.2%) individuals and 16/48 (33.3%) households over the course of the 10-week study period. Study participants attended few social events during this period. However, many participants continued to have regular contact with children. Individuals who had regular contact with preschool and school aged children (i.e., 2-9 year olds) had a higher prevalence of carriage (15.9% vs 5.4%). ConclusionsDespite COVID-19-related disruptions, a large proportion of older adults carried pneumococcus at least once during the 10-week study period. Prevalence was particularly high among those who had contact with school-aged children, but carriage was not limited to this group.