People queue up in front of a hospital near Delhi during a COVID-19 vaccination drive. Credit: Subhra Priyadarshini
An international research team has developed an intra-nasal vaccine candidate that could provide broad protection against current and future SARS-CoV-2 variants1.
SARS-CoV-2, which causes COVID-19, has a positive-sense RNA genome that encodes proteins, including the spike protein which is the target of most vaccines. New variants with mutations in the spike protein have made existing vaccines less effective.
Researchers at Indian Immunologicals, Telangana, in collaboration with Griffith University in Australia and other partners, used codon deoptimization (CDO) to create a panel of live-attenuated vaccine candidates. CDO is a genetic engineering technique that doesn't change the protein's amino acid sequence but reduces the efficiency of viral protein synthesis.
A single dose of CDO-7N-1, one of the vaccine candidates, triggered strong immune response, including neutralizing antibodies and T-cell responses. It provided strong protection from SARS-CoV-2 infection in mice, hamster and macaque models, showed significantly reduced viral growth in vitro and was highly attenuated in vivo.
CDO-7N-1 induced immunity to all major SARS-CoV-2 proteins and is highly effective against all major variants to date. The vaccine was also stable after multiple passages in cell cultures and animals, showing no signs of reversion to virulence.
The vaccine candidate could potentially offer longer-lasting immunity and better protection against emerging variants, the researchers say.
