“Between June 1, 2020 and May 10, 2022, 3,982,250 new cases of covid-19 infection were registered in BI SINAVE. Add to this value 194,244 episodes of reinfection, according to the proposed definition, which make up 4.65% of the total notifications”, states a technical report from the DGS.
According to the document, the prevalence of cases of reinfection is highest in the period when the Ómicron variant of SARS-CoV-2 is more frequent, with a proportion of 6.10%, surpassing the approximately 2% of the period in which that the Delta and Alpha variants were predominant, and only 0.35% at the time of the original variant identified in Wuhan, China.
Cases registered on the BI SINAVE platform - National Epidemiological Surveillance System - are considered suspects of reinfection when there is a positive test after 90 days of the last episode of infection, as defined by the World Health Organization.
“The emergence of the Ómicron variant of concern changed the probability of reinfection, with reinfection being five times more likely than with the variant of concern Delta”, indicates the technical report, adding that, in order to maintain the accuracy and reliability of the process of epidemiological surveillance, it was necessary to update the methodology for counting cases, incorporating suspicions of reinfection.