Omicron’s latest subvariants may have evolved to target the lungs, raising concerns that the next wave of Covid may begin.
Hospital admissions for patients with Covid in England have started to rise again, new NHS data show.
The World Health Organization has been investigating two sub-variants of Omicron since April to determine whether they are more infectious or dangerous than their predecessor. Both BA.4 and BA.5 have been added to the Agency’s watch list.
Last week, new data showed that Covid-19 infections in the UK rose 43% in the week following the platinum anniversary celebrations, with the two new sub-options believed to be behind the sudden increase.
In addition, about 1.4 million people in the United Kingdom had coronavirus in the week ending June 11, up from about 990,000 the previous week.
There was a jump in the Covid-infected week after the platinum anniversary celebrations
(Getty)
According to preliminary data from Kay Sato of the University of Tokyo and colleagues, BA.4, BA.5 and BA.2.12.1 may have evolved to prevent infection of lung cells rather than upper respiratory tract tissue, which makes it more similar to earlier variants, such as Alpha or Delta.
The tendency of earlier versions of Omicron to prefer to infect non-lung tissue may be one of the reasons why infections are milder in most people.
“Overall, our investigations show that the risk of [these] Omicron variants, especially BA.4 and BA.5, for global health are potentially larger than the original BA.2, ”said Sato.
Professor Sato’s experiments show that BA.4, BA.5 and BA.2.12.1 reproduce more efficiently in human lung cells than BA.2, while additional experiments with hamsters suggest that BA.4 and BA.5 may cause more severe illness.
“These things seem to be returning to a more dangerous form of infection, so they go lower in the lungs,” said Dr. Stephen Griffin, a virologist at the University of Leeds.
The total number of infected has already returned to the levels last seen in early May, but remains well below the record 4.9 million at the peak of the Omicron BA.2 wave at the end of March. Admission to Covid Hospital is also below the levels recorded during the previous wave.
ONS said the recent increase was “probably caused by infections compatible with Omicron variants BA.4 and BA.5”, which are now considered the most dominant variants in much of the UK.
Sub-options BA.4 and BA.5 become the most dominant
(PA)
Professor Christina Peigel, director of the Department of Clinical Operations Research at University College London, reiterated this.
“While jubilee celebrations would certainly not help,” she said, “the current wave is accelerated mainly by the fact that BA.4 / BA.5 and BA.2.12.1 are becoming dominant and causing a new surge, probably due to the larger ability to avoid immunity from previous infection and vaccines. “
Dr Mary Ramsey of the UK Health Security Agency said: “It is encouraging that we are not seeing an increase in admission to intensive care units, but we are closely monitoring the data and assessing the potential impact of sub-options BA.4 and BA.5.
“When we enter the summer, it is still important to remember that Covid-19 has not disappeared, and to get vaccinated to reduce the risk of serious illness from the virus.
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