New Covid Booster Strengthens Immune Response Against Subvariants, Moderna Says
The biggest hurdle for vaccines — and a major reason researchers don’t yet have a vaccine — is the fact that different strains of viruses can make the same antibodies — for example, a vaccine that targets a virus found in bats might not work with a virus that is more common in cats or monkeys, according to Moderna, the company running the vaccine (an honor it shares with Pfizer).
The company says its new vaccine addresses this issue by using a single protein that can bind to different types of virus in different ways. In its vaccine, called VRP-121, the protein works in two basic ways to kill different influenza strains — binding to a protein on the surface of the virus, which makes the virus less likely to get into cells to replicate, and binding to a protein on the surface of cells, which makes the cells less likely to engulf the virus.
Moderna has spent $500 million on its vaccine over the past year, but it is still far from perfect. It says the new vaccine also increases the survival rate for mice by “70-90 percent.”
“It has been very challenging to test such a concept in humans because of the difficulty in identifying broadly neutralizing Abs against A(H3N2),” said Moderna co-founder and CEO John P. Rini, “so we decided to design the most stringent surrogate assay for antiviral immunity using a well-established antibody capture method.”
Moderna also says its vaccine is the first to identify which portions of the virus are important for the immunogenicity of the protein. It has created a panel of viruses that contain a few changes on their surface, but those changes do not make the virus more likely to make the immunogen or alter its ability to infect cells.
The virus also doesn’t block binding between the vaccine and the immune system, and the vaccine is safe, Pini says.
“Our new immunogen will be evaluated using high-throughput antibody screening followed by a full-scale high-dose challenge model. If successful, we expect to have one or two shots off the development path to human trials within the next 18 months,” he told TechCrunch. That’s a great first step to being able to protect people against infection.
The company’s VRP-121 is the