Evidence map›Paper›PMID 42102123›Full record

ArticlePloS one2026

Differences in the long-term course of post-COVID-19 symptoms in adults and children across epidemic periods: A retrospective cohort study in Japan, 2020-2024.

Aya Sugiyama, Toshiro Takafuta, Kanon Abe, Yayoi Yoshinaga, Ko Ko, Tomoki Sato, Tomoyuki Akita, Masao Kuwabara, Shingo Fukuma, Junko Tanaka

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Article in PloS one, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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0citing papers in PubMed
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1 · What the graph read from it

What it found

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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

10 authors.

Aya SugiyamaDepartment of Epidemiology Disease Control and Prevention, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.ORCID https://orcid.org/0000-0002-8087-4319
Toshiro TakafutaHiroshima City Funairi Citizens Hospital, Hiroshima, Japan.
Kanon AbeDepartment of Preventive Gerontology, Center for Gerontology and Social Science, National Center for Geriatrics and Gerontology, Aichi, Japan.
Yayoi YoshinagaDepartment of Epidemiology Disease Control and Prevention, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
Ko KoDepartment of Epidemiology Disease Control and Prevention, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
Tomoki SatoHiroshima City Funairi Citizens Hospital, Hiroshima, Japan.
Tomoyuki AkitaDepartment of Epidemiology Disease Control and Prevention, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
Masao KuwabaraHiroshima Prefecture Center for Disease Control and Prevention, Hiroshima, Japan.
Shingo FukumaDepartment of Epidemiology Disease Control and Prevention, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
Junko TanakaDepartment of Epidemiology Disease Control and Prevention, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundThe prevalence of post-COVID-19 symptoms has been reported to decline since the Omicron variant became predominant. However, differences in their long-term course across epidemic periods and between adults and children, including recent Omicron sublineages, remain insufficiently understood.

methodsWe extended a previously reported retrospective cohort by conducting follow-up and an additional survey in Hiroshima, Japan. The study included 2,689 individuals diagnosed with COVID-19 between March 2020 and June 2024 (1,524 adults and 1,165 children). A self-administered questionnaire captured the presence and duration of 13 symptoms. Interval-censored survival analysis estimated prevalence over time, and proportional hazards models evaluated factors associated with symptom resolution.

resultsAt six months, the estimated prevalence in adults was highest during the Delta period (47%) and lower during Omicron-2022 (23%) and Omicron-2024 (21%). In children, prevalence remained about one-quarter to one-third that of adults, with no notable differences between Omicron sublineages. At two years, persistent symptoms were reported by about 20% of adults infected before Omicron and 10% during Omicron periods, compared with 4.1% and 1.9% of children infected during the Delta and Omicron-2022 periods. Symptoms persisting beyond two years showed little further resolution, though in children they did not interfere with daily activities. In the Cox model, resolution was slower during the Delta period (HR 0.79) and faster during Omicron-2022 (HR 1.24) and Omicron-2024 (HR 1.30). Younger age, particularly ≤12 years, was strongly associated with faster recovery.

conclusionThe long-term course of post-COVID-19 symptoms differed across epidemic periods and age groups. The risk was highest during Delta and lower among children and those infected during Omicron waves, yet some individuals experienced symptoms for over two years. Long-term follow-up and social support remain crucial to mitigate the burden of post-COVID-19 condition.

Indexed as

COVID-19AdolescentAdultAgedChildChild, PreschoolFemaleHumansJapanMaleMiddle AgedPandemicsPost-Acute COVID-19 SyndromePrevalenceRetrospective StudiesSARS-CoV-2

Identifiers

PMID42102123
PMCPMC13155679

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.