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. 2023 Feb 8;76(3):e1012-e1020.
doi: 10.1093/cid/ciac734.

The Spectrum of Influenza in Children

Gregory Hoy  1 , Guillermina Kuan  2   3 , Roger López  2   4 , Nery Sánchez  2 , Brenda López  2 , Sergio Ojeda  2   3 , Hannah Maier  1 , Mayuri Patel  1 , Steph Wraith  1 , Alyssa Meyers  1 , Lora Campredon  1 , Angel Balmaseda  2   4 , Aubree Gordon  1
Affiliations

The Spectrum of Influenza in Children

Gregory Hoy et al. Clin Infect Dis. .

Abstract

Background: Children constitute an important component of the influenza burden and community transmission, but the frequency of asymptomatic infection and post-influenza sequelae at the community level is poorly understood.

Methods: Two community-based prospective cohort studies (2011-2020, 2017-2020) and 1 case-ascertained study (2012-2017) were conducted in Managua, Nicaragua. Non-immunocompromised children aged 0-14 years with ≥1 influenza infections, determined by polymerase chain reaction and hemagglutination inhibition assay, were included.

Results: A total of 1272 influenza infections occurred in the household-based portion of the study. Influenza infection was asymptomatic in 84 (6.6%) infections, and the asymptomatic fraction increased with age (1.7%, 3.5%, and 9.1% for ages 0-1, 2-4, and 5-14, respectively; P < .001). Of asymptomatic children, 43 (51.2%) shed virus, compared to 1099 (92.5%) symptomatic children (P < .001). Also, 2140 cases of influenza occurred in the primary care portion of the study. Sequelae of influenza were rare, with the most common being pneumonia (52, 2.4%) and acute otitis media (71, 3.3%). A/H1N1 had higher age-adjusted odds of acute otitis media (odds ratio [OR] 1.99, 95% confidence interval [CI]: 1.14-3.48; P = .015) and hospitalization (OR 3.73, 95% CI: 1.68-8.67; P = .002) than A/H3N2. B/Victoria had higher age-adjusted odds of pneumonia (OR 10.99, 95% CI: 1.34-90.28; P = .026) than B/Yamagata.

Conclusions: Asymptomatic influenza infection is much less common in children than adults, although viral shedding still occurs in asymptomatic children. Post-influenza sequelae are rare in children in the community setting, and virus strain may be important in understanding the risk of sequelae.

Keywords: asymptomatic influenza; clinical presentation; global health; influenza; pediatrics.

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Conflict of interest statement

Potential conflicts of interest. A. G. serves on a scientific advisory board for Janssen Pharmaceuticals and has consulted for Gilead Sciences. G. H. reports support for attending meeting and/or travel from NIAID contract number HHSN272201400006. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.

Figures

Figure 1.
Figure 1.
Flow diagram depicting HITS, HICS, and NPICS enrollees, inclusion/exclusion criteria, and final analytical subsets for the household studies and NPICS. Abbreviations: HICS, Household Influenza Cohort Study; HITS, Household Influenza Transmission Study; NPICS, Nicaraguan Pediatric Influenza Cohort Study.
Figure 2.
Figure 2.
Point estimate and 95% CIs for the fraction of infections that were asymptomatic for (A) children aged 0–14 y versus individuals aged ≥15, and (B) children aged 0–14 y, stratified by age group. The categorical trend in asymptomatic fraction by age tested using the Cochran-Armitage test for trend. The difference in asymptomatic fraction between children and adults tested with the χ2 test. Abbreviation: CI, confidence interval.
Figure 3.
Figure 3.
Point estimates and 95% CIs for the proportion of asymptomatic and symptomatic infections that exhibit viral shedding for (A) children aged 0–14 versus individuals aged ≥15, and (B) children aged 0–14 stratified by age group and individuals ≥15. The categorical trend in asymptomatic fraction by age tested using the Cochran-Armitage test for trend. Abbreviation: CI, confidence interval.
See this image and copyright information in PMC

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