The woman, a Spanish healthcare worker, had a delta and then an Omicron
Spanish researchers said a 31-year-old health care worker contracted the coronavirus twice within 20 days – the shortest known period of time between two infections.
Tests show that the woman was infected with two different mutants – delta in late December and omicron in January.
Researchers say this shows that even if you’ve had the coronavirus before, you can still get infected again even if you get fully vaccinated.
The known period of infection twice in the UK is 90 days.
Based on this definition, health officials say it is likely that nearly 900,000 people may have contracted the coronavirus twice as of the beginning of April.
It is difficult to determine the exact number, because only complete genome sequencing can confirm that the infection is caused by different strains.
The Spanish woman did not show any symptoms after her first positive test, but less than three weeks later she developed a cough and fever, which prompted her to take another test.
When the tests were analyzed further, the results showed that the patient had been infected with two different strains of coronavirus.
In a presentation at the European Conference on Clinical Microbiology and Infectious Diseases, study author Dr. Gemma Risio said the case showed that Omicron can “avoid prior immunity acquired either from natural infection with other mutant or from vaccines”.
“In other words, people who have previously been infected with the coronavirus cannot assume that they are protected from reinfection, even if they have been fully vaccinated,” she said.
“However, it appears that both previous infection with other variants and the vaccines partially protect against severe symptoms and hospitalization in Omicron patients,” added Recio, who works at the Instituto Catala de Salute in Tarragona, Spain.
And she continued, by saying: Monitoring the re-infection of the virus for people who have been fully vaccinated is important, and will help in the search for variants that avoid vaccines.
Corona virus cases rose sharply in December 2021 after the emergence of the most contagious and widespread omicron mutant, and there was another increase when a slightly different strain of it called “PA2” appeared in early March.
Before that, a second infection represented just one percent of all cases recorded in the UK – but that proportion has now risen to 11 percent.
Most are likely to have had previous alpha or delta mutants and then re-infected with the more infectious omicron.
Scientists expect that each person will eventually be infected with the Corona virus twice, and possibly several times, over the course of his life.