Pediatric cases of COVID-19 constitute between 1% to 10% of all confirmed cases of COVID-19; variation exists by jurisdiction.
Few case reports exist of confirmed child-to-other transmission. Contact tracing studies suggest that children are unlikely to be transmitters of the disease. Households are the most likely environments for transmission.
A recent large South Korean contact tracing study however (in pre-print) found that household COVID-19 transmission rates for children age 10-19 were significantly higher than in adults; transmission rates for children age 0-9 were relatively low.
AUGUST 7th, 2020 UPDATE: No new studies examining secondary attack rates of pediatric index cases were found. Studies continue to suggest low transmission from pediatric cases, and high proportion of pediatric cases being asymptomatic to mildly symptomatic.
MARCH 9th, 2021 UPDATE: Variants of Concerns are an emerging threat, but literature on pediatric prevalence and transmissibility is sparse. The British variant seems more transmissible (secondary attack rate higher) but follows the same age-related distribution of cases seen earlier in the pandemic.
Sulaiman, F; Coomaran, V; Muhajarine, N; Dalidowicz, M; Miller, L. What are the effects of the new COVID variants on transmission and school reopenings in pediatric populations? 2021 Mar 30; Document no.: PH030801 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 14p. (CEST rapid review report)
Howell-Spooner, B., Mueller, M. What are the effects of the new COVID variants on transmission and school reopenings in pediatric populations? 2021 Aug 18, Document no.: PH030801v2 ESR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. 49 p. (CEST evidence search report).
Miller, L; Young, C. What is the epidemiology of variants and what are the implications for healthcare? 2021 Feb 22; Document no.: EOC022201-01 ESR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 28 p. (CEST evidence search report)
November 23, 2021
- Delta dominance - Delta continues to account for most of variants sequenced from surveillance data from Public Health Ontario, Public Health England and ECDC.
- The Delta sub-lineage AY.4.2 (Delta plus) accounts for a slowly increasing proportion of Delta cases in the UK. However, evidence is still emerging on its effect on vaccine efficacy and disease severity.
- Increased disease severity (hospitalization) has been observed in adults 18 to 49 years during Delta variant dominance and has been attributed to the low vaccination rates among this age group.
- Epidemiological models predict a new wave of infection if measures such as NPIs are relaxed due to changes in immune escape capability and transmissibility of variants.
- While of moderate certainty, evidence exists to suggest the Delta variant is associated with a higher secondary attack rate, especially among unvaccinated populations.
Key Findings
November 12, 2021
- Emerging data suggest the Delta variant can initiate fast-rising outbreaks in populations with immune responses to prior variants, resulting in reinfections and vaccination breakthroughs. However, we have low certainty of evidence at this point. - A quarter of Delta-associated outbreaks in Ontario were reported in elementary school settings for the week of September 12 to September 18, 2021.
- Full vaccination against COVID-19 has been reported to be more effective in protecting against Delta infection and severe illness (hospitalization and ICU admissions) than partial vaccination.
- Effective protection for essential workers and prompt surveillance of occupational health in the workplace are needed due to disproportionate Delta variant infection among workers such as cleaners.
- While the certainty is low, evidence exists to suggest that a lower gross domestic product (GDP) per capita, higher diabetes prevalence, higher cardiovascular disease rate, and lower percentage of fully vaccinated people have been reported as predictors of higher Delta variant Case Fatality Rate (CFR)
Asamoah, G; Badea, A; Lee, S; Shumilak, G; Reeder, B; Groot, G; Muhajarine, N; Hernandez-Ronquillo L; Miller, L; Howell-Spooner, B. What is the epidemiology of variants and what are the implications for healthcare? 2021 Nov 23. Document no.: EOC031801v017 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. 48 p. (CEST rapid review report).
Asamoah, G; Badea, A; Hernandez-Ronquillo, L; Lee, S; Shumilak, G; Reeder, B; Groot, G; Muhajarine, N; Miller, L; Howell-Spooner, B. What is the epidemiology of variants and what are the implications for healthcare? 2021 Nov 23. Document no.: EOC031801v017 RR Table. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. (CEST table).
Howell-Spooner, B; Miller, L. What is the R0 (basic reproduction number) of the new coronavirus variant detected in the UK? 2020 Dec 31; Document no.: INF123001-01 ESR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 8 p. (CEST evidence search report)
