Universal vaccine

Animal-tested new vaccine blocks coronavirus and its variants, as well as other human coronaviruses

Marina Astvatsaturyan, Echo of Moscow

Scientists from the Duke Human Vaccine Institute at Duke University in North Carolina have created a new vaccine that effectively protects monkeys and mice from coronavirus infection, including SARS-CoV-2, as well as the previous SARS-CoV-1 and related bat coronaviruses that may cause future pandemics. The new vaccine, called the pan-coronavirus vaccine, is based on special nanoparticles. They consist of a part of the coronavirus itself, through which it binds to human cells, and are supplemented with a chemical immune response enhancer, an adjuvant. Success in primates is critically important for human trials, according to a press release from New Vaccine Blocks COVID-19 and Variants, Plus Other Coronaviruses.

The new vaccine was described by its creators in the journal Nature (Saunders et al., Neutralizing antibody vaccine for pandemic and pre-emergent coronaviruses).

"We started this work last spring, realizing that, like all viruses, the SARS-CoV-2 virus that causes COVID-19 will have mutations," says lead author of the publication Barton F. Haynes, head of the North Carolina Vaccine Institute. "mRNA-based vaccines were already being created at that time, so we were looking for ways to maintain their effect as soon as new variants of the virus appeared," he added. The antibodies initiated by the new vaccine neutralize not only SARS-CoV-2, but also the British, South African and Brazilian variants of the coronavirus, and in addition interact with a fairly wide panel of coronaviruses.

The idea of creating a pan-coronavirus vaccine arose from the authors while studying the respiratory disease caused by the SARS-CoV-1 virus. They found a patient who, after this infection, developed antibodies that neutralize many coronaviruses, and realized that this was possible. The Achilles heel of coronaviruses is a special section of the spike protein that attaches it to receptors on human cells, this is the so–called Receptor Binding Domain (RBD). It is highly conservative, the same for all coronaviruses. Thanks to it, the virus enters the body, but this site can also be a target of antibodies. The new vaccine consists of nanoparticles with a receptor-binding domain exposed to the outside, with 24 copies of it on each nanoparticle. In addition to the viral site, nanoparticles contain small molecules that enhance the immune response, which are called toll-like receptors, and aluminum-potassium alum, which also activate immunity. In tests on macaques, the nanoparticle vaccine blocked a variety of coronavirus infections with 100 percent effectiveness. 

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