Optimizing the sensitivity of detection of respiratory syncytial virus infections in longitudinal studies using the combination of weekly sample testing and biannual serology

Category	Detail
Condition	Respiratory Syncytial Virus (RSV) infections
Key Mechanisms	Combination of weekly nasal RT-qPCR testing and biannual serological antibody assessments (IgG and IgA) to detect RSV infections
Target Population	Maternal–child dyads from birth to 18–24 months of age
Care Setting	Longitudinal cohort research setting with home-based sample collection and in-clinic blood draws

Weekly nasal swabs tested by RT-qPCR combined with biannual serology increases RSV infection detection sensitivity compared to RT-qPCR alone.
Classification and regression tree analysis identified specific antibody log10 fold-change thresholds (IgG > 0.32 or IgA > 0.20) indicative of RSV infection.
Using combined methods, cumulative RSV incidence increased from 49% (RT-qPCR only) to 75%, and incidence rate from 0.33 to 0.71 infections/child-year (P < .001).

Use weekly mid-turbinate nasal swabs tested by RT-qPCR for RSV detection in longitudinal cohorts.
Incorporate biannual serological testing measuring RSV pre-fusion F IgG and IgA antibodies to identify infections missed by RT-qPCR.
Define RSV infection by RT-qPCR positivity or a log10 antibody increase exceeding thresholds (IgG > 0.32 or IgA > 0.20).

Ensure high participant adherence to weekly sampling (≥70% recommended) to optimize infection detection.
Use combined RT-qPCR and serology data to better estimate RSV incidence and inform vaccine effectiveness studies.

Monitor weekly sample submission rates to identify adherence levels and potential selection bias.
Perform biannual serological assessments at 6 weeks and every 6 months up to 24 months of age.

Incomplete adherence to weekly sampling may underestimate RSV incidence and introduce selection bias.
Relying solely on symptomatic sampling underestimates asymptomatic infections and total disease burden.

Children enrolled in birth cohorts from birth to 24 months with frequent respiratory sampling

Enhanced detection methods improve understanding of RSV infection burden, critical for vaccine development and evaluation.

Combine frequent RT-qPCR nasal swab testing with periodic serological antibody measurements to maximize RSV infection detection.
Apply antibody fold-change thresholds validated by classification and regression tree analysis to identify incident infections.
Maintain high sample adherence (≥70%) to reduce misclassification and selection biases in longitudinal infectious disease studies.

Clinical Scorecard: Enhancing Detection Sensitivity of Respiratory Syncytial Virus Infections in Longitudinal Research Through Weekly Sampling and Biannual Serological Assessments