New York, Sep 30 (IANS): US-based biotech company Moderna's Covid-19 vaccine candidate has shown signs of working in older adults, new results from an early stage trial have revealed.

This study evaluated a two-dose vaccination schedule of Moderna's Covid-19 vaccine candidate mRNA-1273 given 28 days apart in 40 healthy adult participants across two dose levels -- 25 and 100 microgram -- in two age cohorts --ages 56-70 and ages 71+.

These results, published in the New England Journal of Medicine, showed that both the 25 microgram and 100 microgram dose levels were generally well-tolerated in both age cohorts, with no serious adverse events reported one month after the second dose.

"These interim Phase 1 data suggests that mRNA-1273, our vaccine candidate for the prevention of Covid-19, can generate neutralizing antibodies in older and elderly adults at levels comparable to those in younger adults," Tal Zaks, Chief Medical Officer of Moderna, said in a statement.

"Given the increased morbidity and mortality of Covid-19 in older and elderly adults, these data give us optimism in demonstrating mRNA-1273's protection in this population, which is being evaluated in the Phase 3 COVE study."

Immune responses were dose-dependent with the 100 microgram dose eliciting higher binding and neutralising antibody titers, supporting the selection of the 100 microgram dose for further study in the Phase-3 trial.

The study was led by the National Institute of Allergy and Infectious Diseases (NIAID), part of the US National Institutes of Health (NIH).

The most common solicited adverse events were headache, fatigue, myalgia, chills, and pain at the injection site, the majority of which were mild-to-moderate in severity and of self-limited duration, Moderna said.

The US government has agreed to purchase 100 million doses of mRNA-1273, with an option to purchase an additional 400 million doses.