New research has found that influenza-like illness (ILI) in certain populations can lead to worse pneumococcal colonization of airways that may persist after recovery.
Pneumococcal disease is strongly associated with respiratory viral infections in older adults; however, the impact of viruses on Streptococcus pneumoniae carriage prevalence and load remains poorly understood. This prospective observation study investigated the effects of ILI on pneumococcal carriage in community-dwelling older adults.
In total, 232 adults aged 60 years or older with ILI and 194 age-matched control adults without ILI were included. During the 2014 to 2015 influenza season, participants contacted the study center if they had fever (>37.8 C) and a sudden onset of cough, rhinorrhea, sore throat, headache, chest pain, or myalgia. Patients who reported ILI symptoms provided saliva samples within 72 hours of symptom onset, 2 to 3 weeks after symptom onset, and 7 to 9 weeks after symptom onset. Patients in the control group provided 2 saliva samples 2 to 3 weeks apart.
Results showed that pneumococcal abundances were persistently elevated in the ILI group compared with the control group; however, there was no difference in prevalence of pneumococcal carriage between groups. Overall, 25% of patients with ILI (57/232) and 18% of patients in the control group (35/194) tested positive for pneumococcus at least once during the study. Pneumococcal absolute abundances were significantly higher at onset of ILI when compared with carriers in the control group (P <.01) and remained elevated after recovery from ILI (P <.05).