COVID-19: results by age from SI-VIC, SI-DEP and VAC-SI pairings

### **attention: these data will no longer be updated after 23 June 2023** As part of its mission to support the management of the health crisis, the Directorate of Research, Studies, Evaluation and Statistics (DREES) uses pseudonymised data from the three main databases on the Covid-19 crisis: Si-VIC (hospitalisation), SI-DEP (screening) and VAC-SI (vaccination). These farms lead to numerous analyses, published or for use by crisis management actors, on the three themes: screening, hospitalisation and vaccination. DREES also makes crossovers between these bases, in order to shed light on issues that fall under several of these themes in a joint way. Thus, a regular follow-up according to the vaccination status of the number of positive cases in the Covid-19 tests and hospital admissions is carried out. Similarly, comparative analyses of the frequencies of severe Covid-19 cases depending on the variant or identified mutations of the virus affecting patients may be conducted. These data cover all ages and France as a whole. The percentages of the Omicron variant among the positive tests are estimated via a proxy on the screened tests. These percentages are not significant before the onset of the Omicron variant. NB: changes in the management of the Covid epidemic earlier this year have had an impact on data quality. Since February 1, 2023, in order to receive a test result certificate, the patient must have previously consented to the sharing of his personal data for this purpose. The constitution of the pseudonym (non-signifying character string uniquely identifying each person) took place from 1 February upstream of SI-DEP for people who do not give their consent for the sharing of their personal data, so that they are not integrated into the information system, while ensuring epidemiological surveillance. DREES found anomalies on the pseudonyms received for the tests validated since 1 February. These anomalies degraded the quality of SI-DEP matching with other SI-VIC and VAC-SI data sources. Investigations have made it possible to identify several causes for anomalies concerning the pseudonym in this stream and corrective actions have been implemented prior to the sending of pseudonymised data to the DREES. These corrections were fully operational from the data collected on 17 February, without the possibility of correcting the previous days. **For this reason, the test data for the period from 1 to 16 February are not disseminated in the datasets published by the DREES (the columns related to SI-DEP, for the period from 1 to 16 February are therefore not included).**