Omicron subvariants evade vaccines better than previous COVID strains

omicron subvariants
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Evidence from a Columbia University Vagelos College of Physicians and Surgeons study reveals that vaccines and antibody treatments are less effective against newly discovered omicron subvariants.

The newest omicron subvariants, such as the BA.4 and BA.5 strains of COVID, have caused a surge in infections around the world and are believed to be more transmissible than previous variants. Novel research suggests that these omicron subvariants have become increasingly prevalent due to their ability to evade vaccines and antibody treatments.

The study is titled “Antibody evasion by SARS-CoV-2 Omicron subvariants BA.1.12.1, BA.4 and BA.5.

The rise of omicron subvariants

Around the world, the omicron subvariants BA.2.12.1, BA.4, and BA.5 are becoming increasingly common, as seen in the United States, where the BA.4 and BA.5 subvariants are responsible for more than 50% of new COVID cases.

Due to a range of new mutations in the virus’ spike protein, these subvariants are believed to be more virulent than previous omicron subvariants.

David D. Ho, MD, the study’s leader and director of the Aaron Diamond AIDS Research Center and the Clyde’56 and Helen Wu Professor of Medicine at Columbia University Vagelos College of Physicians and Surgeons, commented: “The virus is continuing to evolve, as expected, and it is not surprising that these new, more transmissible subvariants are becoming more dominant around the world.

“Understanding how currently available vaccines and antibody treatments stand up to the new subvariants is critical to developing strategies to prevent severe disease, hospitalisations, and deaths—if not infection.”

Overriding vaccines and antibody treatments

In a series of laboratory experiments, the research team analysed the ability of antibodies from people who received at least three doses of an mRNA COVID vaccine or had two vaccine doses and were then infected with omicron, to neutralise these new omicron subvariants.

The researchers did not analyse patients who had not received a COVID booster vaccine due to an earlier study suggesting that two doses provide little protection against infection from earlier omicron variants.

The results illuminated that although BA.2.12.1 is only slightly more resistant to vaccines than BA.2, the BA.4 and BA.5 strains were at least four times more resistant.

Additionally, the team examined the effectiveness of 19 monoclonal antibody treatments at neutralising BA.2.12.1, BA.4, and BA.5, finding that only one treatment was effective against all subvariants.

Ho concluded: “Our study suggests that as these highly transmissible subvariants continue to expand around the globe, they will lead to more breakthrough infections in people who are vaccinated and boosted with currently available mRNA vaccines. Though the current study suggests that the new variants may cause more infections in vaccinated individuals, the vaccines continue to provide good protection against severe disease.

“Efforts in the United States to develop new vaccine boosters aimed at BA.4 and BA.5 may improve protection against infection and severe disease. In the current environment, though, we may need to look toward developing new vaccines and treatments that can anticipate the ongoing evolution of the SARS-CoV-2 virus.”


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