According to new research, the omicron sub-variants that have emerged as dominant in recent months pose a severe danger to the efficacy of the new boosters, render antibody therapies useless and might result in an increase in breakthrough infections.

Scientists from Columbia University and the University of Michigan have determined that the BQ.1, BQ.1.1, XBB, and XBB.1 omicron sub-variants are the most immunologically evasive versions of Covid-19 to yet. According to information from the Centers for Disease Control and Prevention, these variations collectively are responsible for 72% of new infections in the United States.

According to the researchers’ findings, these sub-variants are “barely sensitive to neutralization” by the vaccinations, including the novel omicron boosters, which were published online on Tuesday in the peer-reviewed journal Cell. Moreover, people who experienced breakthrough infections with previous omicron variants and received the vaccine also exhibited lower immune responses to the sub-variants.

Together, our results show that BQ and XBB sub-variants pose major risks to the current COVID-19 vaccinations, make all permitted antibodies inactive, and may have become dominant in the population due to their prowess at dodging antibodies, the researchers concluded.

The researchers noted that the vaccinations were effective at avoiding hospitalization and severe sickness from omicron, even if these sub-variants are more prone to result in breakthrough infections.

Blood samples from individuals who received three or four doses of the original vaccines, those who received the new omicron boosters following three doses of the original vaccines, and people who received the original shots but also experienced breakthrough infections caused by the BA.2 or BA.5 sub-variants were all examined in the study.

Antibodies that prevent infection were 24 times lower in those who received the omicron boosters against BQ.1, 41 times lower in those who received BQ.1.1, 66 times lower in those who received XBB, and 85 times lower in those who received XBB.1 compared to their performance against the ancestral strain that first appeared in Wuhan, China, in 2019.

However, the study found that those who received the omicron boosters had somewhat greater antibody levels against these sub-variants than those who received three or four doses of the initial vaccinations.

Although neutralization was also significantly lower against the sub-variants than the ancestor strain, people who had been immunized and experienced breakthrough infections had the highest antibody levels of any group in the research.

The sub-variants of omicron have dramatically diverged from earlier iterations. For example, the study found that BQ.1.1 is almost as distinct from omicron BA.5 as the latter subvariant is from the original Covid strain.

It is concerning that these recently discovered sub-variants “may further undermine the efficiency of existing COVID-19 vaccines and result in a rise of breakthrough infections, as well as re-infections,” according to the researchers.

The largest obstacle, though, is XBB.1. According to the study, compared to the BA.5 subvariant, it is around 49 times more resistant to antibody neutralization. Fortunately, according to CDC data, less than 1% of infections in the U.S. are now caused by XBB.1.

XBB is responsible for 4.7% of new infections, according to CDC statistics, whereas BQ.1.1 and BQ.1 account for 37% and 31% of new infections, respectively.

Antibodies prove ineffective

Evusheld and bebtelovimab, two essential antibody medications, were “totally inert” against the novel subvariants, the study found. People with weakened immune systems are the ones who often employ these antibodies.

To avoid Covid in those with weakened immune systems which don’t respond well to immunizations, Evusheld is an antibody cocktail. In addition, organ transplant recipients and other people who cannot tolerate alternative therapies can use bebtelovimab to stop Covid from advancing to a severe condition.

The authors stated that this “poses a severe concern for millions of immunocompromised patients who do not respond strongly to COVID-19 vaccinations.” Therefore, developing active monoclonal antibodies for clinical usage is crucial.

Because bebtelovimab is no longer effective against the predominant omicron variations in the United States, the Food and Drug Administration has already revoked its drug authorization nationwide. Therefore, the only available pre-exposure prophylactic option is still Evusheld.

For the week ending December 7, the CDC reported that there were 459,000 new Covid infections, an increase of roughly 50%. In addition, nearly 3,000 Covid fatalities occurred in the same week, an increase of 61%. According to the statistics, hospital admissions increased in November before plateauing at 4,700 per day on average.

At a press conference last month, Dr. Anthony Fauci, the chief medical advisor to the White House, said that health officials in the United States are hoping that the population has built up enough immunity from immunization, infection, or both to avert the severe increase in infections and hospitalizations that the country experienced when omicron first arrived in the country last winter.