Estimating influenza transmission parameters: Comparing two study designs, 2023-2024
Recommended Citation
Biddle JE, House S, Kwon JH, Presti RM, Fritz SA, Curley T, McLaren SH, Stockwell MS, Schmitz J, Talbot HK, Grijalva CG, Saade EA, Albar Z, Murugan V, Cruz RA, Martin ET, Vaughn IA, Wernli KJ, Wickersham BM, Zimmerman RK, Geffel KM, Gaglani M, Smith ME, Walter EB, Bontrager NAB, Bristol L, Price AM, Chung JR, Flannery B, Rolfes MA, and Mellis AM. Estimating influenza transmission parameters: Comparing two study designs, 2023-2024. Epidemics 2026;54:100888.
Document Type
Article
Publication Date
3-1-2026
Publication Title
Epidemics
Keywords
Humans, Influenza, Human, United States, Family Characteristics, Adult, Male, Female, Adolescent, Middle Aged, Child, Contact Tracing, Prospective Studies, Young Adult, Child, Preschool, Aged, Research Design, Infant
Abstract
Household studies play a critical role in estimating influenza transmission parameters, which are essential for real-time modeling of epidemic and pandemic dynamics to inform influenza control strategies. We compared two approaches for estimating household influenza transmission parameters from multisite studies conducted in the United States during the 2023-2024 influenza season: interviewing index cases about illnesses among household contacts (n = 1537 contacts) and prospective enrollment of index cases and their household contacts with systematic, daily symptom assessment and testing (n = 857 contacts). We compared the detection of symptomatic illness, influenza-like illness (ILI; fever and either cough or sore throat), influenza virus infection, and estimated serial illness onset intervals among household contacts across studies. Symptomatic illness episodes among household contacts were identified in 40 % of contacts by index case interview compared to 59 % of contacts from individual daily follow-up. Reports of ILI were more comparable between platforms (20 % vs. 26 % respectively). Index case interviews identified 12 % of household contacts with positive influenza tests while systematic, daily testing in the individual daily follow-up platform identified influenza infection among 44 % of household contacts. Both platforms yielded a median serial interval of 4 days. While index case interviews offer rapid, resource-efficient data collection and can inform epidemiological outcomes such as age-related risks and serial intervals, they substantially underestimate laboratory-confirmed influenza cases compared to systematic daily follow-up. These findings highlight the importance of study design in accurately capturing transmission dynamics and underscore the need for systematic laboratory testing to inform public health responses.
Medical Subject Headings
Humans; Influenza, Human; United States; Family Characteristics; Adult; Male; Female; Adolescent; Middle Aged; Child; Contact Tracing; Prospective Studies; Young Adult; Child, Preschool; Aged; Research Design; Infant
PubMed ID
41547041
Volume
54
First Page
100888
Last Page
100888
