Key Points

• COVID-19 Surveillance

  • Multi-source;

  • Enabling the tracking and description of the epidemic;

  • First-time implementation of a system to centrally and responsively aggregate all diagnostic tests for a disease (SI-DEP available starting in May 2020) and vaccination data (VAC-SI).

• Study period for this BSP

  • From March 2020 to May 2021, just before the emergence of the Delta variant, which is still circulating today.

• Epidemic dynamics in Réunion (March 2020 – May 2021)

  • Epidemic resurgences during each school vacation period, against a backdrop of rising numbers of imported cases prior to each peak, with insufficient vaccination coverage;

  • March to May 2020: local viral circulation delayed until July–August 2020, thanks to the implementation of the first and only lockdown that Réunion experienced;

  • June to December 2020: First wave, limited in scope during the second half of 2020 (maximum incidence rate of 80 per 100,000 inhabitants)

  • January to May 2021: Second wave, beginning in early January 2021 and particularly among young adults. Circulation was less intense (TI max of 153 per 100,000 inhabitants) and shorter-lived than in other regions. A brief period of strain on hospitals in March 2021, following an increase in the number of locally transmitted cases (linked to the spread of the Beta variant) and medical evacuations from countries in the Indian Ocean region.

• Key Data for Réunion (March 2020 – May 2021)

  • Nearly 827,800 tests conducted;

  • 2,055 hospitalizations, including 517 in intensive care, and 186 deaths in the hospital;

  • 354 cases reported by sentinel intensive care units; median age of 62 years; presence of comorbidities in over 83% of them; median length of stay of 7 days, resulting in death in 20% of cases (primarily among people aged 65 and older with comorbidities). Obesity, high blood pressure, and diabetes were the main risk factors among patients admitted to an intensive care unit;

  • 2,447 emergency department visits for suspected COVID-19, of which 901 were followed by hospitalization. The peak weekly activity rate in emergency departments for this reason was 3.3% in 2021-S12;

  • 49% of people aged 75 and older had received one dose of the vaccine; 38% had completed the full vaccination series by the end of May 2021;

  • Nearly 1,300 genomes sequenced (from January to May 2021): identification of the introduction of the Beta variant, which became dominant within a few weeks.