India's ‘warm’ vaccine candidate effective against Delta, Omicron variants in mice: Study

A heat-stable COVID-19 vaccine that is being developed in India and does t need cold chain stor has generated strong antibody response against coronavirus variants, including Delta and Omicron, according to a study on mice.

vaccine candidate, by Indian Institute of Science (IISc) in Bengaluru and biotech start-up company Mynvax, uses a part of viral spike protein called receptor-binding domain (RBD), which allows virus to connect with host cell to infect it.

team, including researchers from Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO), ted that most vaccines require refrigeration to remain effective. heat-tolerant COVID-19 vaccine candidate can be stored at 37 degrees Celsius for four weeks and at 100 degrees Celsius for up to 90 minutes.

In comparison, Oxford-AstraZeneca vaccine, kwn as Covishield in India, must be kept between 2-8 degrees Celsius and Pfizer preventive requires specialised cold stor at minus 70 degrees Celsius.

Findings of study

latest study, published recently in journal Viruses, assessed vaccinated mice sera (blood samples) for efficacy against key coronavirus variants, including Delta and Omicron.

study found that mice immunised with different formulations of vaccine elicit high titres (unit to measure amount or concentration) of antibodies that neutralise SARS-CoV-2 variants VIC31 (reference strain), Delta and Omicron variants of coronavirus.

Compared to VIC31, re was an aver 14.4-fold reduction in neutralisation against Omicron variant for one formulation of Mynvax vaccine and a 16.5-fold reduction for ar formulation.

corresponding values for reduction in neutralisation against Delta variant were 2.5 and 3, according to researchers.

" aver 14.4- or 16.5-fold reduction in neutralisation against Omicron BA.1.1 for momeric and trimeric formulations, respectively, compares favourably with equivalent reductions observed with leading COVID-19 vaccines,” authors of study ted.

“Our findings suggest that momeric formulations are suitable for upcoming Phase I human clinical trials and that re is potential for increasing efficacy with vaccine matching to improve responses against emerging variants,” y wrote in journal.

Momeric and trimeric formulations refer to different shapes and combinations that can be used to develop vaccine.

CSIRO's evaluation of different Mynvax formulations will support selection of most suitable candidate and dos for planned human clinical trials in India.

heat tolerance of vaccine and its ability to withstand transient rmal shocks is particularly promising to address vaccine inequity that affects most low- and lower-middle-income countries, researchers added.

Over 10 billion doses of COVID-19 vaccines have been administered globally and 51 countries have reached more than 70 per cent of ir population. However, this is only 11 per cent in low-income countries.