Longitudinal testing for SARS-CoV-2 RNA in day care centers in Hesse, Germany, during increased local incidence and with VOC Alpha as dominant variant: Results of the SAFE KiDS 2 and SAFE KiDS 3 study

Abstract

In the summer of 2020, we investigated the rate of inapparent shedding of SARS-CoV-2 in a representative sample of day care centers from Hesse, Germany, and found a low positivity rate during a period of low local community spread. To investigate the influence of a high local incidence setting, we conducted the SAFE KiDS 2 study. 577 children and 334 staff members of 47 daycare centers were tested for respiratory and gastrointestinal shedding of SARS-CoV-2, and three infections with SARS-CoV-2 in the infectious period were detected. We conclude that viral shedding occurred infrequently while the original "wild-type" variant was dominant. The more transmissible SARS-CoV-2 variant Alpha (B.1.1.7) became the dominant strain after the SAFE KiDS 2 was concluded. The SAFE KiDS 3 study investigated the impact of the Alpha variant of SARS-Co-2 on inapparent viral shedding in the day care setting. In this study, 756 children and 226 staff members from 46 day care centers provided self-collected saliva swabs, the so-called "Lollipop" swabs, which were tested by RT-PCR. In the four-week study period, none of the participants tested positive for SARS-CoV-2 RNA, demonstrating that inapparent shedding of SARS-CoV-2 in the day care setting was also rare during the dominance of the Alpha variant. The influence of the variant of concern Delta on day care centers has yet to be examined.

SARS-CoV-2 variants of concern in children and adolescents with COVID-19: a systematic review

“…In one study analysing household transmission of the Alpha variant in the USA, the risk of infection was high in both younger children ≤11 years old (78%, 95% CI 51% to 76%) and older children and adolescents 12–17 years old (56%, 95% CI 40% to 72%) with overlapping CIs 18. Compared with the pre-VOC period, a similar or lower risk of infection was reported in three household or school studies for children and adolescents of all age groups when the Alpha variant was predominant 18 19 52. However, in two studies from Israel, including a large hospital study, a higher risk of infection for the Alpha variant than for non-VOCs was described for all paediatric age groups 17 33.…”

“…The risk of becoming infected with a SARS-CoV-2 VOC was analysed in time periods when the Alpha, Delta or Omicron variants were predominant in 15 studies (online supplemental table 11). 15 17–19 33 49–58 Immunity due to previous infection or vaccination appeared to be a relevant factor in determining the risk of infection but these factors were poorly reported in the included studies. Some studies (4/15) summarised the vaccination status of the entire study sample, which ranged from an undefined proportion of partially vaccinated individuals to 70% fully vaccinated, without analysing it at the individual level for adults and children and adolescents 18 49–51…”

“…Six studies evaluated data from Alpha variant outbreaks in daycare centres and compared the risk of infection between children and adults 15 19 52–55. They generally showed a lower attack rate for infection with the Alpha variant ranging from 0% to 27% for young children (mostly ≤6 years old) than for adults (0%–71%).…”

The role of SARS-CoV-2 variants of concern in children and adolescents with COVID-19: a systematic review

“…17 Compared with the pre-VOC period, a similar or lower risk of infection was reported in three household or school studies for children and adolescents of all age groups when the alpha variant was predominant. 17,18,50 However, in two studies from Israel, including a large hospital study, a higher risk of infection for the alpha variant than for non-VOCs was described for all paediatric age groups. 16,19 Data on the risk of infection during the delta predominant time period analysed in four studies comparing children and adolescents to adults were inconclusive.…”

“…17,[56][57][58] Six studies evaluated data from alpha variant outbreaks in daycare centres and compared the risk of infection between children and adults. 14,18,[50][51][52][53] They generally showed a lower attack rate for infection with the alpha variant ranging from 0% to 27% for young children (mostly ≤6 years old) than for adults (0%-71%). However, Children and adolescents and SARS-COV-2 variants of concern: a systematic review there were large variations in attack rates between different facilities or classes at the same facility.…”