BACKGROUND AND PURPOSE:

• Lachassinne et al. (The Lancet Child & Adolescent Health, 2021) assessed the extent to which young children contribute to SARS-CoV-2 transmission

METHODS:

• Cross-sectional, multicenter, seroprevalence study
  • Some daycare centers remained open for key workers’ children during a nationwide lockdown in France (March 15 and May 9, 2020)
• Participants
  • Children and staff who attended one of 22 daycare centers during a nationwide lockdown
  • Hospital staff not occupationally exposed to patients with COVID-19, or to children, were enrolled in a comparator group
• Study design
  • Presence of SARS-CoV-2 antibodies, measured using a rapid chromatographic immunoassay in capillary whole blood
• Protocols in the daycare were strictly enforced
  • Indoor surfaces were disinfected | Daycare staff had to wear a mask all day long, and comply with social distancing measures | Parents screened their children for symptoms | Parents could not enter the daycare center | Children cold not attend if symptomatic
• Primary outcome
  • SARS-CoV-2 seroprevalence

RESULTS:

• Daycare: 327 children | 197 staff
  • Children: mean age 1.9 years
  • Staff: mean age 40 years
• Comparator group: 164 adults
  • Mean age: 42 years
• Raw seroprevalence (not taking into account assay characteristics)
  • Children: 4.3% (95% CI, 2.6 to 7.1)
  • Staff: 7.7% (95% CI, 4.2 to 11.6)
  • Comparators: 5.5% (95% CI, 2.9 to 10.1)
• Seroprevalence after taking into account assay characteristics
  • Children: 3.7% (95% CrI, 1.3 to 6.8)
  • Staff: 6.8% (95% CrI, 3.2 to 11.5)
  • Comparators: 5.0% (95% CrI, 1.6 to 9.8)
• In exploratory analysis, seropositive children were more likely than seronegative children to have been exposed to an adult household member with laboratory-confirmed COVID-19
  • Seropositive children: 43%
  • Seronegative children: 6%
  • Relative risk 7.1 (95% CI, 2.2 to 22.4)

CONCLUSION:

• In a daycare setting with strict infection control protocols, the number of young children with seroprevalence of SARS-CoV-2 antibodies was lower than among the adults
• Seroprevalence among daycare staff was similar to the comparator group who did not have occupational contact with children
• The authors suggest intrafamily transmission was more likely than transmission in daycare centers

Learn More – Primary Sources:

SARS-CoV-2 transmission among children and staff in daycare centres during a nationwide lockdown in France: a cross-sectional, multicentre, seroprevalence study

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