Post-Pandemic Adenovirus Resurgence in Pediatric Respiratory Infections: Insights from Hainan Province

Hainan Province cohort study (children presenting to X hospitals, n≈X, late 2021–mid 2024) documents a marked post‑pandemic resurgence in pediatric adenovirus infections, creating immediate implications for hospital capacity and diagnostic strategy.

Adenovirus positivity rose from 4.87% in 2021 to 11.58% in 2024. Children aged 1–7 years accounted for the highest positivity and concentrated admissions to pediatric wards, pinpointing the age band for targeted prevention and potential immunization strategies. This upward trend persisted across the study period and exceeded pre‑pandemic baseline levels.

Sequencing of ~X pediatric respiratory isolates (collected from Y hospitals between late 2023 and mid‑2024) identified a population‑level shift from HAdV‑C to HAdV‑B, supported by N of sequences = X. The genotype replacement plausibly reflects shifts in population immunity and relative viral fitness that favored HAdV‑B expansion.

Transmission dynamics accelerated with the HAdV‑B surge; cohort data showed a higher proportion of severe cases during the peak, suggesting possible differences in clinical severity patterns. Genotype monitoring is therefore central to anticipating surge characteristics and shaping timely responses.

Targeted next‑generation sequencing (tNGS) increased detection of adenovirus co‑infections from approximately 62% to >85% by 2023. Higher co‑infection detection reframes clinical interpretation toward mixed‑viral etiologies and can influence antimicrobial stewardship and risk stratification. Laboratories should consider tNGS or expanded multiplex testing where available to better define pathogen burden and guide clinical management.

Overall, expanded molecular testing refines case definitions and supports resource allocation in pediatric care during surges.

Key Takeaways:

• Post‑pandemic surveillance documents a clear rebound in pediatric adenovirus positivity, with near‑tripling in some months—hospital preparedness should reflect increased seasonal burden.
• Children aged 1–7 years are most affected; pediatric wards and outpatient clinics should prioritize testing and cohorting in this age band.
• Genotype replacement by HAdV‑B and higher co‑infection detection via tNGS underscore the need for molecular surveillance and expanded diagnostics to anticipate transmission and inform clinical management.