Studying the mutations of the coronavirus, the researchers discovered a new subspecies of the omicron strain – BA.2, which was also given the name “stealth” (stealth – invisible, hidden, English). As experts explain, genetically it is very similar to the classic “omicron” (BA.1). Differences can only be noticed with a thorough study of the genome – sequencing, and with conventional laboratory testing, special features are not visible – hence the “hidden” characteristic.
According to the latest data, another mutant has been recorded in more than 40 countries of the world, including India, South Africa, European countries, the USA and Australia. In Denmark, “stealth-omicron” has already managed to take a dominant position and displace other variants of the causative agent of COVID-19.
The main distinguishing feature of the updated virus is its even higher contagiousness. According to various data , BA.2 spreads 10-30% more actively than the classic “omicron”. Danish researchers also note that “stealth” is even better away from the immunity of those vaccinated and recovered. At the same time, however, vaccines retain a fairly high degree of protection against severe complications. And in the case of a breakthrough infection in vaccinated people (that is, they become infected despite vaccination), such people do not spread the virus more actively than with the usual “omicron”. While unvaccinated individuals who have caught BA.2 become more contagious to others.
TRIAD OF MAIN SYMPTOMS
According to foreign media with reference to the National Health Service of Great Britain (National Health Service, NHS), in terms of symptoms, the stealth omicron is in many ways similar to its predecessor. At the same time, the triad is more often observed in patients:
– persistent cough
– Loss or distortion of smell and taste.
Coughing looks like a particularly worrying sign, but doctors tend to think that it is often not associated with pneumonia. Previously , a study by scientists at the University of Hong Kong showed that “omicron” multiplies in the lungs significantly more slowly than “delta”. Based on this, doctors believe that BA.2 also affects mainly the upper respiratory tract. Therefore, the cough is of a “throat” and not pulmonary nature, said a pulmonologist, candidate of medical sciences Alexander Palman on the air of Moscow-24 .
HOW DANGEROUS IS THE NEW MUTANT?
A Danish study showed that with the spread of the stealth variant, the proportion of hospitalized patients, fortunately, is no higher than with the classic omicron variant. Mortality (that is, the percentage of deaths from all cases) also does not increase. Based on this, at the moment, the BA.2 subtype of coronavirus does not look more dangerous than its predecessor, Anders Vomsgaard, chief physician and virologist at the State Serum Institute in Denmark , told reporters .
At the same time, Mira Chand, an expert on COVID-19 at the British Health Security Agency, notes that there is still not enough data to determine the true severity of the disease in those who have caught stealth omicron. Observation and collection of information continues, the situation will become more or less clear within the next week or two, said Dr. Chand.
In turn, health professionals warn that the spread of a variant of coronavirus with increased contagiousness, even with a relatively low severity of infection, will lead to an even greater overload of clinics and hospitals.