Chinese scientists and their U.S. counterparts have developed two cocktail antibodies against COVID-19 that may deliver a one-two punch to infections caused by the prevalent Omicron variant.

Researchers from the University of Science and Technology of China, the Chinese Academy of Sciences and the University of Texas Health Science Center at San Antonio designed bivalent nanobodies that can provide broad-spectrum protection against SARS-CoV-2 variants of concern including Omicron.

These variants with adaptive mutations have caused fresh outbreaks even amongst vaccinated populations.

In the two new experimental medicines, the researchers fused an antibody called aRBD-2 with another two aRBD-5 and aRBD-7, respectively, according to the study published recently in the journal Cell Research.

The detection of their crystal structures reveals that those three nanobodies can neutralize the coronavirus by binding with a highly-conserved place in the virus's spike protein, according to the study.

Furthermore, aRBD-5 and aRBD-7 are capable of binding to a less-conserved place in the virus protein, thus effectively enhancing the overall binding affinity of the two-in-one antibodies.

The cellular assays demonstrated that the two combined nanobodies, aRBD-2-5 and aRBD-2-7, retain strong neutralization activity against all the tested major variants, including Omicron BA.1, BA.1.1 and BA.2.

In a Syrian golden hamster model, aRBD-2-5 works to eliminate Omicron BA.1 virus, according to the study.

The strategy provides new solutions in the development of broad-spectrum therapeutic antibodies for COVID-19, the researchers said.