A healthcare worker takes a swab sample from a citizen for nucleic acid testing at a testing site in the new Binhai area of Tianjin, northern China on January 9, 2022.
Zhao Zishu | Xinhua News Agency | Getty Images
A health care worker reportedly tested positive for the omicron strain of the coronavirus just 20 days after having an infection caused by the delta variant. according to Spanish researchers.
The case study of the 31-year-old woman, who has been fully vaccinated and potentiated, will be presented by researchers at this year’s European Congress of Clinical Microbiology and Infectious Diseases in Portugal next weekend.
The 20-day gap between infections is the shortest known.
The woman tested positive for the first time on Dec 12 last year in a PCR test while screening staff in the workplace. The patient who did not develop any symptoms isolated himself for 10 days before returning to work.
On January 10 of this year, just 20 days after testing positive for the first time, she developed a cough, fever and was generally sick and did another PCR test. This was so good.
Genome-wide sequencing showed that the patient was infected with two different strains of Covid-19. The woman’s first infection was with the delta variant while the second, in January, was with the more transmissible variant of omicron that was identified as a worrying variant by the World Health Organization last November.
Studies have shown that omcron is much more contagious than delta and can evade the immunity people gain from past infections and Covid vaccination, which protects against serious infections, hospitalization and death.
Since then the omicron variant has started to be supplanted by a sub-variant of the strain, known as BA.2, while other variants have since emerged as well, including one nicknamed XE.
One of the authors of the study, Dr. Gemma Recio of the Institut Català de Salut in Tarragona in Spain, said the case highlights the potential of the omicron variant to circumvent previous immunity acquired from a natural infection with other variants or from vaccines.
“In other words, people who have had Covid-19 cannot assume they are protected from reinfection, even if they have been fully vaccinated,” Recio said.
“However, both prior infection with other variants and vaccination appear to partially protect against serious illness and hospitalization in those with omicron.”
He said the case highlighted the need for genomic surveillance of viruses in infections in those who are fully vaccinated and in reinfections as “the monitoring will help detect variants with the ability to partially evade the immune response.”
The material has been peer-reviewed by the European Congress of Clinical Microbiology and Infectious Diseases Selection Committee, but there is no complete paper at this stage, and the authors have not yet sent the work to a medical journal for publication.