A fully vaccinated 31-year-old woman in Spain caught Covid-19 twice within 20 days. This is said to be the shortest known gap between infections.
The woman healthcare worker was fully vaccinated and had received a booster shot 12 days earlier before she tested positive in a PCR staff screening test at work on December 20, 2021. Following this, she again developed a cough, fever and felt generally unwell on January 10, 2022. So, she did another PCR test. This time also she tested positive.
Researchers in Spain gave details of the healthcare worker, who tested positive a few days before Christmas in December 2021 and again in January 2022. The case is further evidence that the Omicron variant can evade immunity from even recent previous infections, reports said.
“This case highlights the potential of the Omicron variant to evade the previous immunity acquired either from a natural infection with other variants or from vaccines,” The Guardian quotes Dr Gemma Recio, of the Institut Català de la Salut in Tarragona and one of the study’s authors as saying.
She added that the case underlined the importance of genomic surveillance. “Such monitoring will help detect variants with the ability to partially evade the immune response,” she said.
Paul Hunter, a professor in medicine at the University of East Anglia, was quoted as saying: “This case is not particularly surprising, though the gap between infections is particularly short. We have known for some months that reinfections will occur. The Omicron variant with its escape mutations has made reinfections even more likely.”
Now that Omicron is the dominant variant, it is possible that prior infection with Omicron will make reinfection – especially so quickly – less likely. Previously scientists had predicted that as Covid-19 moves into an endemic phase, reinfections are likely to occur within a range of three months to five years.
“We can expect further waves of infection especially during winter even without new variants,” said Hunter. “Fortunately the evidence is that immunity to severe disease is more robust than immunity to infection. So even though reinfections will continue to occur for many years, we will see fewer and fewer severe illnesses and deaths with time,” the report said.