The outbreak is intensifying; prevention must be both individual and collective

In Week 38, in mainland France, viral circulation continued to rise, leading to a worsening of the situation, particularly regarding hospitalizations and deaths. The number of new hospitalizations increased by 34% between Week 37 (2,464 hospitalizations) and Week 38 (3,657). The rise in new ICU admissions is even steeper: a 40% increase in Week 38 (599 vs. 427). The number of COVID-19-related deaths (including deaths in hospitals and deaths in nursing homes and other long-term care facilities) rose from 265 in Week 37 to 332 in Week 38, a 25% increase.

In the absence of a cure or vaccine, preventive measures (hygiene, physical distancing, reducing contact, and proper mask-wearing (see the tutorial)) are our only defenses. Protecting yourself also means protecting others.

An additional indicator for assessing the dynamics of the epidemic

The effective reproduction number (or Reff) is useful for analyzing the dynamics of virus transmission during an epidemic. It can be calculated using various data points: the number of cases, the number of emergency room visits, and the number of hospitalizations. When Reff is significantly greater than 1, the epidemic is spreading.

Through week 37, the epidemiological update included two types of Reff. The first was calculated based on the number of confirmed cases in France (virological data, SI-DEP), the SI-DEP Reff; the second was calculated based on emergency department visit data (OSCOUR®), the OSCOUR® Reff.
The interpretation of the effective R should be considered in conjunction with all other indicators. Currently, the strain on testing resources (testing capacity and delays in reporting results) calls for caution in interpreting the Reff SI-DEP (1.06), which is likely underestimated. This is why, starting this week, the effective R is also being calculated using hospitalization data for COVID-19 cases (SI-VIC data): the SI-VIC effective R (1.28).

• Learn more: What is R, or the virus reproduction number?

Daily Data vs. Consolidated Data: Key Insights

Where does the data come from? Every day, Santé publique France teams receive a vast amount of data from a network of numerous partners. This information is gradually consolidated over a period ranging from a few hours to several days. However, to obtain the most accurate picture possible of the epidemic’s progression, Santé publique France analyzes this data at various points after its receipt.

Daily analyses (upon receipt of the data) provide early information on epidemic trends. They also help alert surveillance teams to the occurrence of an unusual event. This event is then investigated to determine whether it is related to system operations (such as weekend catch-up processing) or whether it constitutes a warning sign.

Analyses following data consolidation are produced several days or even weeks after receipt. This delay allows partners time to report all data and surveillance teams to validate it. The analysis then provides more comprehensive and accurate information. It enables the monitoring of an epidemic as closely as possible to reality.

For example, in the context of SI-VIC surveillance, data comes from healthcare facilities. Between the admission of a patient suspected of having COVID-19 to a healthcare facility and their inclusion in the analyses, several steps are required: confirmation of the diagnosis by the facility’s physicians, transmission of the information to the data entry staff, entry into the SI-VIC database, transmission of the database to Santé publique France, followed by the data investigation and validation stages. The time between each step can vary depending on the situation and the facility. It is important to analyze and communicate the data as soon as it is received—even if it is potentially incomplete and subject to significant variations—as well as after it has been consolidated.