Incidence and Relative Risk of COVID-19 in Adolescents and Youth Compared With Older Adults in 19 US States, Fall 2020

IMPORTANCE: Adolescents have been thought to be low in susceptibility to COVID-19 compared with older adults. Data regarding incidence and risk of COVID-19 are needed to convey risk of infection and inform prevention messaging, especially because US states such as Florida are recommending against vaccinating individuals ages 5 to 17 years and because more infections among adolescents could signal potentially higher incidence of long COVID. OBJECTIVE: To compare incidence rates and relative risk of infection among US adolescents and youth with those of older adults for wild-type SARS-CoV-2. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study included persons living in 19 US states that experienced surges from the start of the pandemic through fall 2020. Participants were all individuals reported as cases on state health department websites for the age groups and states studied. Age groups included adolescents (ages 10 to 19 years), youth (ages 15 to 24 years or 18 to 24 years), adolescents and youth combined (ages 10 to 24 years), and older adults (either age 60 years or 65 years and older), with age thresholds dependent on individual state data. Data were analyzed between June 2021 and January 2022. MAIN OUTCOMES AND MEASURES: Incidence rates for the wild-type SARS-CoV-2 strain; the relative risk of infection in adolescents and youth compared with older adults, based on the incidence rate ratio (IRR). RESULTS: In 16 of 19 states, the IRR of COVID-19 infection in adolescents and youth was significantly greater than in older adults. For example, in Florida, the incidence rate in adolescents and youth was 0.055 compared with 0.028 in older adults—adolescents and youth had 1.94 times the risk of contracting COVID-19 compared with older adults (IRR, 1.94; 95% CI, 1.92-1.95). CONCLUSIONS AND RELEVANCE: Results from this cross-sectional study with US data were contrary to studies from Asia and Europe indicating lower susceptibility of adolescents than older adults. Our findings with the wild-type strain were consistent with findings reported in the UK for the Delta variant and underscored that even with the wild-type lineage, incidence among adolescents and youth exceeded that in older adults.