The Community of Madrid confirms the second case of the Ómicron variant in Spain. This is a case under study: a 61-year-old woman who arrived from South Africa on Monday night after stopping off in Amsterdam. The woman had two doses of the AstraZeneca vaccine. He is currently in quarantine and asymptomatic, as confirmed to the SER string the Ministry of Health, through a spokesperson.
It joins the case confirmed yesterday. A 51-year-old man who arrived in Madrid on Sunday via the same air route. He has mild symptoms and is also in isolation. The man had the full Pfizer guideline.
The two positives for this strain have been confirmed by the Microbiology service of the Gregorio Marañón University Hospital in the capital, the reference for cases that enter through Barajas. Its professionals have put in place a procedure to reduce the time it takes to identify Ómicron. Usually it takes up to four days, but “these response times are not enough for the current situation,” explains Darío García, one of the center’s microbiologists in statements sent to the media. Now they have managed to reduce the deadline to a few hours.
In the first place, when the volume of samples to be sequenced is very high, researchers try to narrow the field. They look for only five mutations that are present in Omicron, although not only. It is not enough to confirm a case, but it is used to screen and make the first discards. This procedure takes about two hours, according to their managers.
Once the number of suspicious samples has been reduced, “an ultra-fast sequencing technique is applied with a nanopore sequencing system,” says García. Basically, the strands of RNA – the genetic material of the virus – are passed through microscopic holes. As they pass, they cause changes in the electrical current that make it possible to identify each element that makes up that RNA sequence.
Typically, this system ‘reads’ up to 96 samples at a time, but when time is short – as now – efforts can be concentrated on a single suspect sample. This allows the sequencing time to be reduced to around five or six hours, albeit at a high economic cost. “We can only do it in situations of extraordinary justification, of high public health alarm,” says the Marañón microbiologist.
Cases in which there is epidemiological suspicion normally undergo an antigen test at the Barajas airport. Then, if applicable, he is referred to this Madrid hospital to carry out the PCR, the test that later allows sequencing the virus with which that patient has been infected. Patricia Muñoz, head of the hospital’s Microbiology service, puts the number of positives registered in the Gregorio Marañón at “more than 70,000”, among which they have identified “some 6,500 strains.” Ómicron is just one of them, but the one that worries the most at the moment, waiting for time and science to determine its transmissibility and the severity of the disease it causes.