Dynamics of Naturally Acquired Immunity Against Severe Acute Respiratory Syndrome Coronavirus 2 in Children and Adolescents

Tal Patalon, Yaki Saciuk, Galit Perez, Asaf Peretz, Amir Ben-Tov, Sivan Gazit

    Research output: Contribution to journalArticlepeer-review

    2 Scopus citations


    Objective: To evaluate the duration of protection against reinfection conferred by a previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in children and adolescents. Study design: We applied 2 complementary approaches: a matched test-negative, case-control design and a retrospective cohort design. A total of 458 959 unvaccinated individuals aged 5-18 years were included. The analyses focused on the period July 1, 2021, to December 13, 2021, a period of Delta variant dominance in Israel. We evaluated 3 SARS-CoV-2–related outcomes: documented polymerase chain reaction–confirmed infection or reinfection, symptomatic infection or reinfection, and SARS-CoV-2–related hospitalization or death. Results: Overall, children and adolescents who were previously infected acquired durable protection against reinfection with SARS-CoV-2 for at least 18 months. Importantly, no SARS-CoV-2–related deaths were recorded in either the SARS-CoV-2–naïve group or the previously infected group. The effectiveness of naturally acquired immunity against a recurrent infection reached 89.2% (95% CI, 84.7%-92.4%) at 3-6 months after the first infection and declined slightly to 82.5% (95% CI, 79.1%-85.3%) by 9-12 months after infection, with a slight nonsignificant waning trend seen up to 18 months after infection. Additionally, children aged 5-11 years exhibited no significant waning of naturally acquired protection throughout the outcome period, whereas waning protection in those aged 12-18 years was more prominent but still mild. Conclusions: Children and adolescents who were previously infected with SARS-CoV-2 remain protected to a high degree for 18 months. Further research is needed to examine naturally acquired immunity against Omicron and newer emerging variants.

    Original languageEnglish
    Article number113371
    JournalJournal of Pediatrics
    StateAccepted/In press - 1 Jan 2023


    • COVID-19
    • infection-induced immunity
    • natural immunity
    • naturally acquired immunity
    • SARS-CoV-2
    • waning immunity

    ASJC Scopus subject areas

    • Pediatrics, Perinatology, and Child Health


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