A national cross-sectional survey of COVID-19 outbreaks in day-care centers during the rapid spread of SARS-CoV-2 alpha variant (B.1.1.7) in England | BMC Public Health

Between 2 November 2020 (week 45) and 31 January 2021 (week 4), 324 day care centers reported a COVID-19 outbreak of PHE, representing 1.0% (324/32,852) of day care centers across England (Fig 1a). The number of eruptions peaked in early November, then declined until late December before increasing again in January and declining again from mid-February to late April 2021 (Fig. 1b).

Fig. 1

Total number of outbreaks in England reported to Public Health England (PHE) between 2 November 2020 and 31 January 2021 (a) the PHE center and the people involved in the PHE investigation and (b) through Epi week, showing proportion of confirmed SARS-CoV-2 community infections attributed to ALPHA (B.1.1.7). variant

Between February 9th and 23rd, 2021, 315 (97%) day-care centers were contacted and 181 (57%) took part in the survey. Eight settings provided insufficient information; Therefore, 173 nurseries from all English regions were included in the analysis (Fig. 1a). There were 1,657 SARS-CoV-2 cases, including 510 (31%) children and 1,147 (69%) employees, related to these outbreaks. A median of 8 (IQR: 5–13; range 2–33) people were affected per outbreak (Table 1). Kindergartens that reported an outbreak organized their children and staff into anywhere from 1 to 10 bubbles. Of the 171 who reported their blistering, 42% (72/171) of the outbreaks were > 3 blisters, 33% (56/171) involved two blisters, and 25% (43/171) involved one blister (Supplementary Table S1) . . A total of 99 facilities closed at least once because of the outbreak (4 closed twice, 1 closed three times), of which 96 indicated how long they had been closed: up to a week (28 daycare centres), 7–13 days (33 daycare centres) or 14– 28 days (35 nurseries). A child was the index case in 45 outbreaks (45/173, 26%) and a staff member in 125 (125/173, 72%) (Table 2). The appearance of COVID-19 symptoms was the most common reason for testing in the first four cases of each outbreak (411/603, 68%), followed by contact with a kindergarten case (92/603, 15%) and contact with a household case (58 /603, 10%) (Supplementary Table S4). There were 28 hospital admissions, including one child, and no deaths.

Table 1 Summary of nursery outbreaks in England reported to Public Health England (PHE) between 2 November 2020 and 31 January 2021
Table 2 Number of SARS-CoV-2 cases and cumulative incidence among staff and students by index case in day care centers that reported an outbreak to Public Health England (PHE) between 2 November 2020 and 31 January 2021

Cumulative incidence among staff and students

Overall, children had a cumulative incidence of 3.50% (95% CI, 3.21-3.81%) compared to 30.92% (95% CI, 29.44-32.44%) among staff ( Table 1). In children, the cumulative incidence of SARS-CoV-2 was highest in the <1 year olds (5.76%; 95% CI, 4.08-8.04%) and decreased with age, with 4- year-olds had the lowest cumulative incidence (2.75%). , 95% CI, 2.10-3.58%) (Fig. 2). Personnel with direct contact with children had the highest cumulative incidence (32.94%; 95% CI, 31.30-34.62%), followed by personnel without direct contact (20.20%, 95% CI, 17.08 -23.72%) (Table 1).

Fig. 2
figure 2

Cumulative incidence per 1,000 children attending a nursery school in England who reported a COVID-19 outbreak between 2 November 2020 and 31 January 2021 and were subsequently screened by Public Health England (PHE). Error bars indicate 95% confidence intervals

The cumulative incidence was lowest in children, regardless of whether the index case was a child (3.55%; 95% CI, 3.01-4.19%) or a staff member (3.44%; 95% CI, 3.10-3.82%). Among staff, the cumulative incidence was lower overall when the index case was a child (26.28%; 95% CI, 23.54-29.21%) compared to a staff member (32.98%; 95% CI, 31.19-34.82%). the highest cumulative incidence among direct workers when the index case was also a direct worker (37.52%; 95% CI, 35.39-39.70%) (Table 2). Compared to November 2020, when the alpha variant was hardly transmitted in England, the number of cases, median and type of people affected per outbreak and the cumulative incidence in children and staff in January 2021 were higher than it nearly all cases were nationwide due to alpha variant, while the number of reported outbreaks for these two months was similar (64 vs. 66) (Table 1).

Facilities, social distancing and infection control measures

Kindergartens that experienced a COVID-19 outbreak reported that 49% (85/172) of their staff were able to maintain physical distance from each other most of the day, while 39.5% (68/172) reported observing social distancing “rarely”, “never”, or “sometimes”. Within individual bubbles, day care centers reported that 74% (127/172) of children were “never” able to maintain physical distance from one another and 64% (110/172) of staff were “never” able to maintain physical distance children ( Complete Table S2). Across all bubbles, 50% (83/166) of daycares reported their staff were able to maintain physical distancing throughout the day from staff in other bubbles, and 61% (102/166) of children were in the Able to maintain physical distancing Distancing children from other bubbles “all the time” (Supplementary Table S2).

Around two-thirds of the daycare centers had shared staff rooms (111/170, 65%) and 78% (131/169) had shared bathrooms shared by staff from different bubbles. Most settings had designated dining areas (146/169, 86%) and children’s bathrooms (112/168, 67%) assigned per bladder (Supplementary Table S3). Fifty-seven percent (99/173) of the daycares reported that staff did not provide cross-coverage across bladders.

National Surveillance

Nationally, weekly SARS-CoV-2 infection rates were lowest in children aged < 5 years and followed the same trends as the older age groups (Fig. 3a and b). For example, cases in children aged <5 years slowly increased after all schools fully reopened in September 2020 (week 36) and decreased during the nationwide lockdown in November 2020 when educational institutions remained fully open to all students. Cases then increased from late November 2020 following the emergence of the alpha variant in England until late 2020 before falling. In January and February 2021, as England entered its third national lockdown, cases continued to fall across all age groups, including the <5 year olds, at a time when kindergartens remained open while primary and secondary schools had limited attendance and could be attended -Individual classes for vulnerable children and children of key workers. Among the < 5 year olds, the highest weekly infection rates were in infants (< 1 year old) and decreased with age (Fig. 3a and b).

Fig. 3
figure 3

Weekly laboratory-confirmed SARS-CoV-2 infection rates per 100,000 in England (a) by age groups and (b) by age in years for children under 5 years old

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