Assessment of temporally-related acute respiratory illness following influenza vaccination.

BACKGROUND: A barrier to influenza vaccination is the misperception that the inactivated vaccine can cause influenza. Previous studies have investigated the risk of acute respiratory illness (ARI) after influenza vaccination with conflicting results. We assessed whether there is an increased rate of laboratory-confirmed ARI in post-influenza vaccination periods. METHODS: We conducted a cohort sub-analysis of children and adults in the MoSAIC community surveillance study from 2013 to 2016. Influenza vaccination was confirmed through city or hospital registries. Cases of ARI were ascertained by twice-weekly text messages to household to identify members with ARI symptoms. Nasal swabs were obtained from ill participants and analyzed for respiratory pathogens using multiplex PCR. The primary outcome measure was the hazard ratio of laboratory-confirmed ARI in individuals post-vaccination compared to other time periods during three influenza seasons. RESULTS: Of the 999 participants, 68.8% were children, 30.2% were adults. Each study season, approximately half received influenza vaccine and one third experienced ≥1 ARI. The hazard of influenza in individuals during the 14-day post-vaccination period was similar to unvaccinated individuals during the same period (HR 0.96, 95% CI [0.60, 1.52]). The hazard of non-influenza respiratory pathogens was higher during the same period (HR 1.65, 95% CI [1.14, 2.38]); when stratified by age the hazard remained higher for children (HR 1·71, 95% CI [1.16, 2.53]) but not for adults (HR 0.88, 95% CI [0.21, 3.69]). CONCLUSION: Among children there was an increase in the hazard of ARI caused by non-influenza respiratory pathogens post-influenza vaccination compared to unvaccinated children during the same period. Potential mechanisms for this association warrant further investigation. Future research could investigate whether medical decision-making surrounding influenza vaccination may be improved by acknowledging patient experiences, counseling regarding different types of ARI, and correcting the misperception that all ARI occurring after vaccination are caused by influenza.

Pilot study of participant-collected nasal swabs for acute respiratory infections in a low-income, urban population.

OBJECTIVE: To assess the feasibility and validity of unsupervised participant-collected nasal swabs to detect respiratory pathogens in a low-income, urban minority population. METHODS: This project was conducted as part of an ongoing community-based surveillance study in New York City to identify viral etiologies of acute respiratory infection. In January 2014, following sample collection by trained research assistants, participants with acute respiratory infection from 30 households subsequently collected and returned a self-collected/parent-collected nasal swab via mail. Self/parental swabs corresponding with positive reverse transcription polymerase chain reaction primary research samples were analyzed. RESULTS: Nearly all (96.8%, n=30/31) households agreed to participate; 100% reported returning the sample and 29 were received (median time: 8 days). Most (18; 62.1%) of the primary research samples were positive. For eight influenza-positive research samples, seven (87.5%) self-swabs were also positive. For ten other respiratory pathogen-positive research samples, eight (80.0%) self-swabs were positive. Sensitivity of self-swabs for any respiratory pathogen was 83.3% and 87.5% for influenza, and specificity for both was 100%. There was no relationship between level of education and concordance of results between positive research samples and their matching participant swab. CONCLUSION: In this pilot study, self-swabbing was feasible and valid in a low-income, urban minority population.