Researchers at the Tokyo Metropolitan Institute of Medical Science are working on a COVID-19 vaccine that not only delivers lifelong immunity against the SARS-CoV-2 virus but could also be transported at room temperature to far-off corners of the world, The Japan Times reported.
As infections caused by the Omicron variant surge across the world, countries may soon face the difficult choice of either imposing strict lockdowns or letting the variant run through the population. Vaccinations are reducing the severity of the disease but are ineffective in halting the spread of the highly transmissible infection. As vaccine companies rush to develop variant-specific booster doses that might become the norm in this pandemic that will soon enter its third calendar year, the news of a single vaccine that can last a lifetime is highly welcome.
The vaccine that is being developed by Michinori Kohara and his team of researchers employs the most successful vaccine used in history, one against smallpox. The team uses a strain of the vaccinia virus that does not cause disease but replaced some of its protein components with those from the SARS-CoV-2 spike protein.
While recombining the spike protein with a different delivery mechanism is a common strategy used in vaccine design these days, Kohara is confident that his vaccine can not only deliver potent neutralizing antibodies with a single dose, they also induce strong cellular immunity that offers long term protection.
Experiments conducted in mice showed that vaccinated mice maintained high antibody levels for over 20 months or their average lifetime, The Japan Times reported. When two doses were administered, three weeks apart, the neutralizing antibodies increased tenfold, the report said.
Similar experiments conducted in macaques showed that vaccine protected them from infection as virus levels in the vaccinated macaques remained lower than detection limits, seven days after they were infected with the coronavirus.
Kohara also told the news outlet that the vaccine would offer an added advantage of producing fewer side-effects compared to other vaccines that have been given emergency-use authorizations. The non-pathogenic strain used in the vaccine design is incapable of replicating in mammals and would produce fewer side-effect reactions, Kohara claimed.
The researchers have tested the vaccine against the four previously reported coronavirus variants of concern and found it to be effective. Kohara told the media outlet that he expects it to work against Omicron as well while also stating that the vaccine could be stored at room temperatures making them easy to transport and administer in developing countries with tropical climates.
The Tokyo Metropolitan Institute of Medical Science does not have previous experience of commercializing a vaccine and has signed up domestic drugmaker Nobelpharma Co to take it through clinical trials. The first and second phases of human clinical trials are expected to begin only in 2023 followed by a larger phase trial immediately if no efficacy and safety concerns pop up. If all goes well, the vaccine may be commercially available from 2024, at the earliest, The Japan Times reported.