Study participants (N=1278) who were current or former agriculture workers were recruited from the Clínica de Salud del Valle de Salinas in California between July and November 2020. All participants were recommended to test for COVID-19 infection and were asked to provide saliva samples for pneumococcal carriage testing regardless of symptoms. Carriage of pneumococcus and COVID-19 were determined by quantitative polymerase chain reaction (qPCR) testing.
Among the study population, 564 participants were recruited at outpatient clinics and 714 participants were recruited at mobile outreach clinics. A total of 9.2% of participants had pneumococcal carriage, in which the carriage rate was higher among participants attending the outpatient clinics than the mobile outreach clinics (11.2% vs 7.6%), respectively.
The rate of COVID-19 infection was 41.3% among those who carried pneumococcus compared with 13.8% among those who did not carry pneumococcus. Stratified by subgroups, the COVID-19 positivity rate was consistently higher among pneumococcus carriers than non-carriers among women (25.9% vs 10.1%), indigenous speakers (37.9% vs 16.5%), and individuals living in houses with more than 4 people per bedroom (50.0% vs 17.2%).
Overall, COVID-19 positivity was associated with pneumococcal carriage among all individuals (adjusted odds ratio [aOR], 2.73; 95% CI, 1.58-4.69), individuals with no COVID-19 symptoms (aOR, 2.79; 95% CI, 1.26-6.24), and with COVID-19 symptoms in the previous 2 weeks (aOR, 3.38; 95% CI, 1.35-8.40). Stratified by recruitment site, risk for COVID-19 based on pneumococcal carriage was significantly higher among individuals recruited at a clinic (aOR, 4.01; 95% CI, 2.08-7.75) but not at a mobile outreach clinic (aOR, 0.95; 95% CI, 0.20-4.44).
Stratified by lytA and piaB gene positivities and cycle thresholds (CT), risk for COVID-19 positivity was associated with every 1-unit decrease in piaB CT (aOR, 1.24; 95% CI, 1.00-1.55), but not in lytA CT (aOR, 0.94; 95% CI, 0.81-1.09).
The study may have been limited as social linkage was not evaluated and it is possible that some study participants could have lived and/or worked together.
The study authors conclude, “Whereas IPD incidence declined precipitously during the early COVID-19 pandemic, this pattern may have been driven by reduced transmission of other viruses and frequent antibiotic treatment of COVID-19 patients who would otherwise be at risk.”
Disclosure: An author declared affiliations with industry. Please refer to the original article for a full list of disclosures.
Parker AM, Jackson N, Awasthi S, et al. Association of upper respiratory Streptococcus pneumoniae colonization with SARS-cov-2 infection among adults. Clin Infect Dis. 2022;ciac907. doi:10.1093/cid/ciac907