BA.2 variant effectively threatens many 'weapons' against Covid-19

Japan's Kei Sato noted that BA.2 should not be viewed as a fork of Omicron and this variant should be monitored more closely.

A new study shows that the BA.2 virus - a sub-variant of Omicron, not only spreads faster than the original variant, but also has the ability to cause more severe disease and reduce the effectiveness of some 'weapons' main' that we use to fight Covid-19.

 Japanese scientists discovered many worrying signs of variant BA.2.

Disturbing findings

New laboratory studies in Japan show that BA.2 has properties that make it more likely to cause severe Covid-19 symptoms than older variants, such as Delta. Like Omicron, it seems to avoid the immunity created by vaccination. BA.2 is also resistant to a number of treatments, including the drug sotrovimab - a class of monoclonal antibodies currently used against Omicron.

The new findings were published on the open data science portal bioRxiv on February 16. Dr. Daniel Rhoads, head of microbiology at the Cleveland Clinic in Ohio (USA), said: 'According to research, it can be seen that BA.2 is a "worse" virus than BA.1 because of its transmissibility. more easily and cause more severe illness. Mr. Rhoads was the one who reviewed the bioRxiv report but was not involved in the research process.

Compared to the SAR-CoV-2 virus that causes Covid-19 disease, which originally appeared in Wuhan, China, BA.2 has more mutations. It also has dozens of genetic variations, different from the original Omicron strain, and also different from many other variants such as Alpha, Beta, Gamma and Delta.

People wear masks to prevent Covid-19 in Tokyo, Japan, February 9.

The findings suggest that BA.2 should not be viewed as an offshoot of Omicron and that this variant should be monitored more closely, said Kei Sato, an expert at the University of Tokyo, who carried out the study.

Speaking to CNN, Mr. Kei Sato said: 'BA.2 is called 'stealth Omicron'. That's because it's not easy to detect with a PCR test. While Omicron is detectable by PCR due to the lack of the S gene, BA.2 does not have this genetic property. Therefore, laboratories need to sequence the gene to find it."

"Building a method to detect BA.2 will be the first thing that many countries need to get wrong", this expert emphasized.

"Maybe we'll need a new Greek letter," said Deborah Fuller, a virologist at the University of Washington School of Medicine. Many data show that BA.2 is about 30 to 50% more contagious than Omicron. It has been detected in 74 countries and 47 US states.

There are still positive signals

The US Centers for Disease Control and Prevention estimates that about 4% of the US population has been infected with BA.2. According to the World Health Organization (WHO), BA.2 has become the dominant variant in 10 countries: Bangladesh, Brunei, China, Denmark, Guam, India, Montenegro, Nepal, Pakistan and the Philippines.

However, there is mixed evidence about the severity of BA.2. Hospitalization rates continued to decline in countries where BA.2 was endemic, such as, South Africa and the UK. But in Denmark, where BA.2 is becoming the leading cause of Covid-19, the number of hospitalizations and deaths is increasing day by day, the WHO said.

Research shows that BA.2 can self-replicate in cells faster than BA.1 (original version of Omicron). It also makes it easier for cells to stick together, to form a large cell mass, called a syncytium. This is really worrisome because these syncytial cells then become 'factories' for making multiple copies of the virus. Delta also has the ability to efficiently produce syncytial cells, and many have suggested that this may be the reason why it is so prone to ravaging the lungs.

When the researchers transplanted BA.1 and BA.2 into hamsters, those infected with BA.2 experienced more severe symptoms and poorer lung function. In diseased samples, the lungs of mice infected with BA.2 were more damaged than those of mice infected with BA.1.

Similar to the original Omicron version, BA2 has the ability to disrupt antibodies in the blood of people who have been vaccinated against Covid-19. It also has the ability to fight antibodies of people who have been infected with Covid-19, caused by infection with Alpha and Delta variants. More worryingly, BA.2 is almost entirely resistant to some monoclonal antibody treatments.

There's some good news, though: Antibodies in the blood of people who have been recently infected with Omicron may offer protection against BA.2, especially if they've been vaccinated. Fuller said that although BA.2 is more contagious and disease-causing than BA.1, it may not create a more severe Covid-19 wave.

'One of the things we have to think about before working on new variants that seem more dangerous is that each story often has two sides'. "Our immune system is evolving and that will repel any threat," she said.

"We are in a race against the virus, so the key question is who will take the lead?" Fuller said. The last thing we want to do is help the host stay ahead of the virus. In other words, keeping our immunity one step ahead of the next variant'.