Search

Background: In France, the lifting of the lockdown implemented to control the COVID-19 first wave in 2020 was followed by a reinforced contact-tracing (CT) strategy for the early detection of cases and transmission chains. We developed a reporting system of clusters defined as at least three COVID-19 cases, within seven days and belonging to the same community or having participated in the same gathering, whether they know each other or not. The aim of this study was to describe the typology and criticality of clusters reported between the two lockdowns in France to guide future action prioritisation.Methods: In this study we describe the typology and criticality of COVID-19 clusters between the two lockdowns implemented in France (between May and end of October 2020). Clusters were registered in a national database named "MONIC" (MONItoring des Clusters), established in May 2020. This surveillance system identified the most affected communities in a timely manner. A level of criticality was defined for each cluster to take into consideration the risk of spreading within and outside the community of occurrence, and the health impact within the community. We compared the level of criticality according to the type of community in which the cluster occurred using Pearson's chi-square tests.Results: A total of 7236 clusters were reported over the study period, particularly in occupational environment (25.1%, n = 1813), elderly care structures (21.9%, n = 1586), and educational establishments (15.9%, n = 1154). We show a shift over time of the most affected communities in terms of number of clusters. Clusters reported in occupational environment and the personal sphere had increased during summer while clusters reported in educational environment increased after the start of the school year. This trend mirrors change of transmission pattern overtime according to social contacts. Among all reported clusters, 43.1% had a high level of criticality with significant differences between communities (p < 0.0001). A majority of clusters had a high level of criticality in elderly care structures (82.2%), in disability care centres (56.6%), and health care facilities (51.7%).Conclusion: These results highlight the importance of targeting public health action based on timely sustained investigations, testing capacity and targeted awareness campaigns. The emergence of new SARS-CoV-2 variants strengthen these public health recommendations and the need for rapid and prioritise vaccination campaigns. [ABSTRACT FROM AUTHOR]

The aim was to estimate the effect of reported history of smallpox vaccination prior to 1980 on clinical expression of mpox. We included all confirmed mpox cases identified by the national mpox surveillance system in France between May and July 2022. Cases tested positive for monkeypox virus or orthopoxviruses by PCR. Cases were interviewed by phone using a questionnaire documenting demographics, symptoms and exposures. To estimate the effect of smallpox vaccination on the presence of marked mpox symptoms (association of fever, lymphadenopathy and extensive mucocutaneous lesions), we estimated prevalence ratios (PRs) and 95% CIs using Poisson regression models with robust standard errors. There were 1888 confirmed mpox cases with date of symptom onset between 7 May and 31 July 2022. Overall, 7% (93/1394) presented marked mpox symptoms. Among patients who provided information about their vaccination status, 14% (207/1469) reported smallpox vaccination prior to 1980. The proportion of cases with marked symptoms was 2% (3/170) among those reporting smallpox vaccination prior to 1980 and 8% (76/974) among those who reported no vaccination. The proportion of marked symptoms was four times lower among cases reporting previous smallpox vaccination than in cases reporting no vaccination (PR, 0.24; 95% CI: 0.08–0.76). There was no evidence of an effect of smallpox vaccination on development of complications (PR, 0.65; 95% CI: 0.35–1.22) or hospitalization due to mpox (PR, 0.64; 95% CI: 0.23–1.80). Our results suggest that smallpox vaccination during childhood attenuated the clinical expression of monkeypox virus infection, but there was no evidence of an effect on complications or hospitalization. [ABSTRACT FROM AUTHOR]

Background: During 2020-2021, in the context of increasing SARS-CoV-2 transmission in the general population, French authorities made the decision to keep schools open and set up massive screening campaigns for students. Here, we describe the impact of this strategy on the circulation of SARS-COV-2 among children and adolescents during this period., Methods: We analyzed SARS-COV-2 surveillance data provided by the French National Public Health Agency for the 2020-2021 school year along with the results of school-based screening campaigns implemented by the Ministry of National Education., Results: The proportion of 0-17-year-olds among confirmed cases and tested individuals increased throughout the school year, with children and adolescents reaching a maximum of 24 % of confirmed cases in 2021 week (W) 22. During the first semester of 2021 (W3-W22), >2.6 million tests were performed in schools, with a positivity rate of 0.32 % among students. Considering only symptomatic cases, higher incidence rates occurred among children and adolescents during the 2021 wave from W9 to W17 compared with that in 2020 from W40 to W48. The incidence rate did not significantly change following the school closure periods., Conclusion: The higher contribution of children and adolescents to viral circulation during the 2020-2021 school year seems more related to the emergence of the alpha variant than to France's decision to keep schools open. Considering the negative impact of school closures on children's mental health, these results support the decision to keep schools open when accompanied by appropriate control measures., Competing Interests: Declaration of competing interest None., (Copyright © 2024. Published by Elsevier Masson SAS.)