In a recent study, an international team of scientists has compared Omicron’s antibody sensitivity to that of the currently prevalent Delta variant. The study which has been released in the ‘Nature Journal’ aims to see how effective therapeutic antibodies, as well as antibodies created by people who had previously been infected with SARS-CoV-2 or who had been vaccinated, were in neutralising this new strain. 

This research has been supported by the researchers from the Institut Pasteur and the Vaccine Research Institute, in cooperation with KU Leuven (Belgium), Orleans Regional Hospital, Hospital European Georges Pompidou (AP-HP), and Inserm. This has also been assisted by the European Union’s Health Emergency Preparedness and Response Authority (HERA), ANI reported.

Findings of the research  

According to the research, scientists at KU Leuven identified the Omicron strain from a nasal swab of a 32-year-old woman who had mild COVID-19 symptoms just a few days after returning from Egypt. The isolated virus was subsequently forwarded to experts at the Institut Pasteur, who studied the sensitivity of the Omicron variant using therapeutic monoclonal antibodies and blood samples from persons who had been inoculated or earlier infected to SARS-CoV-2. 

Further, on the isolated specimen of the Omicron virus, the researchers employed quick neutralisation tests established by the Institut Pasteur’s Virus and Immunity Unit. The researchers initiated the testing by putting nine monoclonal antibodies in clinical use or in preclinical development. As per the findings of the research, six antibodies had lost their antiviral function completely, and the remaining three were 3 to 80 times less efficient against Omicron than Delta. 

As per the research, antiviral property against Omicron was lost in the antibodies Bamlanivimab/Etesevimab, Casirivimab/Imdevimab, and Regdanvimab (produced by Celtrion). The combination of Tixagevimab/Cilgavimab, manufactured by AstraZeneca as Evusheld, was 80 times less efficient against Omicron than it was against Delta. 

Olivier Schwartz, a co-author of the study and Head of the Institute Pasteur’s Virus and Immunity Unit, said, “We demonstrated that this highly transmissible variant has acquired significant resistance to antibodies. Most of the therapeutic monoclonal antibodies currently available against SARS-CoV-2 are inactive,” ANI reported.  

In addition to this, the researchers noticed that the blood sample of patients who had earlier been afflicted with COVID-19, acquired up to 12 months after symptoms, and that of those who had obtained two doses of vaccine, collected five months after vaccination, were hardly neutralised the Omicron variety. Furthermore, during cell culture experiments, five to 31 times more antibodies were needed to neutralise Omicron than Delta. Thus, these findings offer insight into the vaccinations’ ongoing usefulness in preventing severe forms of the disease. 

The study shows that the Omicron variant hampers the effectiveness of vaccines and monoclonal antibodies

Emmanuel Andre, co-author of the study, a Professor of Medicine at KU Leuven and Head of the National Reference Laboratory as well as the genome surveillance network for COVID-19 in Belgium, stated, “This study shows that the Omicron variant hampers the effectiveness of vaccines and monoclonal antibodies, but it also demonstrates the ability of European scientists to work together to identify challenges and potential solutions,” ANI reported.  

 While concluding, the scientists determined that the Omicron variant’s numerous mutations in the spike protein allowed it to mainly elude the immunological response. Further researches are ongoing to establish why this variety is more communicable from one person to the next, as well as to assess the long-term efficacy of a booster dose. 

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