Key Points

In the last week of 2020, there was an increase in the incidence rate and positivity rate, even as testing activity slowed compared to previous weeks, indicating a resurgence of SARS-CoV-2 transmission in the region.

In week 53 (December 28 to January 3), the number of new confirmed COVID-19 cases increased, with approximately 5,600 new confirmed cases in the region. The incidence rate also increased (+30% between weeks 52 and 53), reaching 93.6 per 100,000 inhabitants. This trend is observed across all age groups, except among those aged 75 and older, where the rate was already the highest but remained stable.

The positivity rate doubled, rising from 1.9% in week 52 to 4.0% in week 53. This increase is observed across all age groups, particularly among children aged 0 to 14. At the same time, the testing rate fell sharply in week 53, with 2,321 tests performed per 100,000 inhabitants compared to 3,650 per 100,000 in week 52, representing a 37% decrease in the testing rate.

This opposite trend in the positivity rate and testing rate is likely linked to a “return to normal” in testing practices. Thus, during the holidays, a surge in people seeking to get tested to avoid exposing their families to the virus led to an increase in precautionary testing among asymptomatic individuals and, consequently, a mechanical decrease in the positivity rate. We are now seeing the opposite phenomenon, with a decrease in the number of tests performed and an increase in the positivity rate linked to a refocusing of testing on symptomatic individuals and close contacts of confirmed cases.