A cross-sectional national investigation of COVID-19 outbreaks in nurseries during rapid spread of the Alpha (B.1.1.7) variant of SARS-CoV-2 in England.

BACKGROUND: In England, the emergence the more transmissible SARS-CoV-2 variant Alpha (B.1.1.7) led to a third national lockdown from December 2020, including restricted attendance at schools. Nurseries, however, remained fully open. COVID-19 outbreaks (≥ 2 laboratory-confirmed cases within 14 days) in nurseries were investigated to assess the risk of SARS-CoV-2 infection and cumulative incidence in staff and children over a three-month period when community SARS-CoV-2 infections rates were high and the Alpha variant was spreading rapidly across England. METHODS: This was a cross-sectional national investigation of COVID-19 outbreaks in nurseries across England. Nurseries reporting a COVID-19 outbreak to PHE between November 2020 and January 2021 were requested to complete a questionnaire about their outbreak. RESULTS: Three hundred and twenty-four nurseries, comprising 1% (324/32,852) of nurseries in England, reported a COVID-19 outbreak. Of the 315 (97%) nurseries contacted, 173 (55%) reported 1,657 SARS-CoV-2 cases, including 510 (31%) children and 1,147 (69%) staff. A child was the index case in 45 outbreaks (26%) and staff in 125 (72%) outbreaks. Overall, children had an incidence rate of 3.50% (95%CI, 3.21-3.81%) and was similar irrespective of whether the index case was a child (3.55%; 95%CI, 3.01-4.19%) or staff (3.44%; 95%CI, 3.10-3.82%). Among staff, cumulative incidence was lower if 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%), with the highest cumulative incidence when the index case was also a staff member (37.52%; 95%CI, 35.39-39.70%). Compared to November 2020, outbreak sizes and cumulative incidence was higher in January 2021, when the Alpha variant predominated. Nationally, SARS-CoV-2 infection rates in < 5 year-olds remained low and followed trends in older age-groups, increasing during December 2020 and declining thereafter. CONCLUSIONS: In this cross-sectional study of COVID-19 outbreaks in nurseries, one in three staff were affected compared to one in thirty children. There was some evidence of increased transmissibility and higher cumulative incidence associated with the Alpha variant, highlighting the importance of maintaining a low level of community infections.

Are People Optimistically Biased about the Risk of COVID-19 Infection? Lessons from the First Wave of the Pandemic in Europe.

Unrealistic optimism, the underestimation of one's risk of experiencing harm, has been investigated extensively to understand better and predict behavioural responses to health threats. Prior to the COVID-19 pandemic, a relative dearth of research existed in this domain regarding epidemics, which is surprising considering that this optimistic bias has been associated with a lack of engagement in protective behaviours critical in fighting twenty-first-century, emergent, infectious diseases. The current study addresses this gap in the literature by investigating whether people demonstrated optimism bias during the first wave of the COVID-19 pandemic in Europe, how this changed over time, and whether unrealistic optimism was negatively associated with protective measures. Taking advantage of a pre-existing international participative influenza surveillance network (n = 12,378), absolute and comparative unrealistic optimism were measured at three epidemic stages (pre-, early, peak), and across four countries-France, Italy, Switzerland and the United Kingdom. Despite differences in culture and health response, similar patterns were observed across all four countries. The prevalence of unrealistic optimism appears to be influenced by the particular epidemic context. Paradoxically, whereas absolute unrealistic optimism decreased over time, comparative unrealistic optimism increased, suggesting that whilst people became increasingly accurate in assessing their personal risk, they nonetheless overestimated that for others. Comparative unrealistic optimism was negatively associated with the adoption of protective behaviours, which is worrying, given that these preventive measures are critical in tackling the spread and health burden of COVID-19. It is hoped these findings will inspire further research into sociocognitive mechanisms involved in risk appraisal.

COVID-19 outbreaks following full reopening of primary and secondary schools in England: Cross-sectional national surveillance, November 2020.

BACKGROUND: The full reopening of schools in September 2020 was associated with an increase in COVID-19 cases and outbreaks in educational settings across England. METHODS: Primary and secondary schools reporting an outbreak (≥2 laboratory-confirmed cases within 14 days) to Public Health England (PHE) between 31 August and 18 October 2020 were contacted in November 2020 to complete an online questionnaire. INTERPRETATION: There were 969 school outbreaks reported to PHE, comprising 2% (n = 450) of primary schools and 10% (n = 519) of secondary schools in England. Of the 369 geographically-representative schools contacted, 179 completed the questionnaire (100 primary schools, 79 secondary schools) and 2,314 cases were reported. Outbreaks were larger and across more year groups in secondary schools than in primary schools. Teaching staff were more likely to be the index case in primary (48/100, 48%) than secondary (25/79, 32%) school outbreaks (P = 0.027). When an outbreak occurred, attack rates were higher in staff (881/17,362; 5.07; 95%CI, 4.75-5.41) than students, especially primary school teaching staff (378/3852; 9.81%; 95%CI, 8.90-10.82%) compared to secondary school teaching staff (284/7146; 3.97%; 95%CI, 3.79-5.69%). Secondary school students (1105/91,919; 1.20%; 95%CI, 1.13-1.28%) had higher attack rates than primary school students (328/39,027; 0.84%; 95%CI, 0.75-0.94%). CONCLUSIONS: A higher proportion of secondary schools than primary schools reported a COVID-19 outbreak and experienced larger outbreaks across multiple school year groups. The higher attack rate among teaching staff during an outbreak, especially in primary schools, suggests that additional protective measures may be needed. FUNDING: PHE.

The impact of social and physical distancing measures on COVID-19 activity in England: findings from a multi-tiered surveillance system.

BackgroundA multi-tiered surveillance system based on influenza surveillance was adopted in the United Kingdom in the early stages of the coronavirus disease (COVID-19) epidemic to monitor different stages of the disease. Mandatory social and physical distancing measures (SPDM) were introduced on 23 March 2020 to attempt to limit transmission.AimTo describe the impact of SPDM on COVID-19 activity as detected through the different surveillance systems.MethodsData from national population surveys, web-based indicators, syndromic surveillance, sentinel swabbing, respiratory outbreaks, secondary care admissions and mortality indicators from the start of the epidemic to week 18 2020 were used to identify the timing of peaks in surveillance indicators relative to the introduction of SPDM. This timing was compared with median time from symptom onset to different stages of illness and levels of care or interactions with healthcare services.ResultsThe impact of SPDM was detected within 1 week through population surveys, web search indicators and sentinel swabbing reported by onset date. There were detectable impacts on syndromic surveillance indicators for difficulty breathing, influenza-like illness and COVID-19 coding at 2, 7 and 12 days respectively, hospitalisations and critical care admissions (both 12 days), laboratory positivity (14 days), deaths (17 days) and nursing home outbreaks (4 weeks).ConclusionThe impact of SPDM on COVID-19 activity was detectable within 1 week through community surveillance indicators, highlighting their importance in early detection of changes in activity. Community swabbing surveillance may be increasingly important as a specific indicator, should circulation of seasonal respiratory viruses increase.

SARS-CoV-2 infection in London, England: changes to community point prevalence around lockdown time, March-May 2020.

BACKGROUND: The UK has been one of the European countries most affected by COVID-19 pandemic. The UK implemented a lockdown in March 2020, when testing policy at the time was focusing on hospitalised cases. Limited information is therefore available on the impact of the lockdown on point prevalence in the community. We assessed COVID-19 point prevalence in London between early April and early May 2020, which approximately reflect infection around the time of the lockdown and 3-5 weeks into lockdown. METHODS: We tested 1064 participants of a community surveillance cohort for acute COVID-19 infection using PCR in London in April and May 2020 and described positivity as well as characteristics and symptoms of the participants. RESULTS: Point prevalence decreased from 2.2% (95% CI 1.4 to 3.5) in early April to 0.2% (95% CI 0.03 to 1.6) in early May. 22% of those who tested positive in April were asymptomatic. Extrapolation from reports of confirmed cases suggest that 5-7.6% of total infections were confirmed by testing during this period. CONCLUSION: COVID-19 point prevalence in the community sharply decreased after lockdown was implemented. This study is based on a small sample and regular seroprevalence studies are needed to better characterise population-level immunity.