Special: Battle against the new coronavirus
The immunity obtained from the original strain is not adequate against later subvariants
People infected with the original version of the Omicron COVID-19 variant virus are vulnerable to reinfection by mutated subsequent subvariants of Omicron, including BA.4, BA.5, and BA.2.12.1, according to a new study. published in the journal Nature. last week.
Researchers warned that vaccine enhancers being developed from the original Omicron strain may not achieve broad-spectrum protection against new Omicron subvariants.
The study found that the natural immunity obtained by becoming infected with the early version of Omicron also does not offer adequate protection against the latest strains, thus disproving the controversial notion that the Omicron variant is a “natural vaccine. “with mild symptoms and that people should be proactively infected to gain immunity against future viral strains.
BA.4, BA.5 and BA.2.12.1 are newly discovered Omicron strains that have shown greater evasion and transmissibility of immunity than their predecessors. They have recently become the dominant strains in the United States, South Africa, and some European countries, but the total number of new cases attributed to these strains is less than the massive wave of Omicron infections that swept the world during the winter of 2021.
Sunney Xie Xiaoliang, a scientist in charge of the study and professor of biochemistry at Peking University, told The Beijing Intellectual Science Network that BA.4, BA.5 and BA.2.12.1 share a mutation called L452. while BA.4. and BA.5 also have an additional mutation called F486V.
These mutations played a key role in increasing the ability of these subvariants to evade antibodies from the original Omicron variant, leading to innovative infections, he said.
Xie said there is still a need to develop booster vaccines that can provide broad-spectrum protection against a number of Omicron strains. This may require advances in protein or mRNA vaccines, but designing a broad-spectrum vaccine is generally very difficult, he added.
As for treatments, Xie said most monoclonal antibody drugs have lost their effectiveness against Omicron subvariants due to new mutations, except for Bebtelovimab and Evusheld.
Scientists may need to find new combinations of antibodies that can target new strains, he said. A candidate combination, i.e. SA58 and SA55, has shown great potency against all Omicron subvariants, but more research is needed to confirm its effectiveness.
“It’s easy to find an antibody that is very powerful in neutralizing the virus, but the key is to find an antibody that is difficult to avoid for the new subvariant,” he said.
These antibodies can also become safe preventative drugs for the Omicron variant, but the downside is that this treatment is currently very expensive, he said. However, the cost can be reduced to a manageable level if production increases or if treatment is only used among highly vulnerable demographics, such as those with compromised immunity, he added.