A Spanish woman, the first documented case of reinfection by COVID-19 in less than three weeks

A 31-year-old Spanish woman who contracted COVID-19 twice in less than three weeks has become the first documented case with the shortest known time gap between infections, according to a report to be presented at this year’s European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) in Lisbon, Portugal, between the April 23 and 26.

Having overcome COVID-19 and being vaccinated is not a guarantee of not suffering a new infection, and according to this report it may occur sooner than expected. Specifically in 20 days. This was the time that this Spanish step from contracting the Delta variant to being infected by Omicron.

The woman, a health worker, gave positive for the first time on December 20, 2021, in a PCR test during the evaluation of staff at their workplace. She was fully vaccinated and had received a booster shot 12 days earlier. The patient, who did not develop any symptoms, was isolated for ten days before returning to work. On January 10, 2022, just 20 days after the first positive test, she developed a cough, fever and felt generally unwell and had another PCR test, which was also positive. Whole genome sequencing showed that the patient had been infected by two different strains of SARS-CoV-2. His first infection, in December, was with the Delta variant. The second, in January, was with the Omicron variant.

The Omicron variant had been identified as a variant of concern by the World Health Organization (WHO) just over a month earlier, on November 26, 2021. The strain, which became the dominant variant worldwide, is much more infectious than Delta and can evade immunity from past infections and vaccinations.

“This case highlights the potential for the Omicron variant to evade previously acquired immunity either from natural infection with other variants or from vaccines. In other words, people who have had COVID-19 cannot assume they are protected against reinfection.” , even if they have been fully vaccinated,” says Dr. Gemma Recio, from the Institut Català de Salut, in Tarragona, one of the authors of the study.

“However, both prior infection with other variants and vaccination appear to partially protect against severe disease and hospitalization in people with Omicron. This case also underscores the need for genomic surveillance of viruses in infections in those who are fully vaccinated and in reinfections. Such monitoring will help detect variants with the ability to partially evade the immune response,” he concludes.