Omicron escapes vaccine, antibody therapies: study
New York- The highly transmissible Omicron variant of Covid-19 has the potential to evade the immune protection conferred by vaccines and natural infections, as well as to render most monoclonal antibody therapies ineffective, according to a new study.
The study conducted by researchers at Columbia University in the United States, in collaboration with scientists at the University of Hong Kong, suggests the need for new vaccines and treatments that anticipate the future course of the virus.
A striking feature of the omicron variant is the alarming number of changes in the virus spike protein that could threaten the effectiveness of current therapeutic vaccines and antibodies.
The new study, published in the journal Nature, tested the ability of immunization-generated antibodies to neutralize the Omicron variant in lab tests that pitted antibodies against live viruses and pseudoviruses built in the lab to mimic Omicron.
The results showed that the antibodies of people doubly vaccinated with one of the four most widely used vaccines – Moderna, Pfizer, AstraZeneca, Johnson and Johnson – were significantly less effective at neutralizing the Omicron variant compared to the ancestral virus.
Antibodies from previously infected individuals were even less likely to neutralize Omicron.
Individuals who received a booster shot of one of the two mRNA vaccines were found to be better protected, although even their antibodies showed decreased neutralizing activity against Omicron.
“The new results suggest that previously infected individuals and fully vaccinated individuals are at risk for infection with the omicron variant,” said David Ho, director of the Aaron Diamond AIDS Research Center at Columbia.
“Even a third booster may not adequately protect against omicron infection, but of course getting one is advisable because you will still have some immunity,” he added.
The results are consistent with other neutralization studies, as well as with early epidemiological data from South Africa and the UK, which show that the efficacy of two doses of the vaccines against symptomatic disease is significantly reduced against the omicron variant.
Additionally, the study suggests that all of the monoclonal antibody therapies currently in use and most in development are much less effective against Omicron, if they work.
When given early in the infection, monoclonal antibodies have been shown to prevent many people from developing severe Covid.
In neutralization studies with monoclonal antibodies, only one (Brii198 approved in China) maintained notable activity against Omicron. A minor form of Omicron is completely resistant to all antibodies in clinical use today, the researchers said.
The researchers note that Omicron is now the most complete “escape” from neutralization that scientists have seen.
In this study, Ho’s lab also identified four new cutting edge mutations in the omicron that help the virus escape antibodies, suggesting the need for new approaches to combat the variant.
“It is no exaggeration to think that SARS-CoV-2 is just a mutation or two to be completely resistant to current antibodies, whether they are the monoclonal antibodies used as therapies or the antibodies generated by the vaccination or infection with previous variants, “said Ho. (IANS)