New York, June 3 : In a ray of hope against Covid-19, Massachusetts-based biotechnology giant Moderna has commenced stage 2 trials for its new coronavirus vaccine and aims to enrol 600 participants, up from 45 participants in the phase 1 trials. According to Forbes, Moderna is looking to start phase 3 trials by July for its vaccine candidate named mRNA-1273. "Phase 2 trials may be viewed as more crucial compared to other phases for a couple of reasons. While phase 1 trials are used to ascertain the safety of a vaccine or treatment in humans, phase 2 trials gauge the effectiveness and also provide more data on how safe it is," said the report on Tuesday. Based on historical data, the probability of success for a drug moving from phase 1 of clinical trials to phase 2 stands at about 63 per cent. US stocks surged as investors eyed some encouraging news about a potential coronavirus vaccine. Last month, the Moderna mRNA vaccine showed promising results by generating an immune-system response in the body to fight coronavirus. mRNA-1273 is an mRNA vaccine against SARS-CoV-2 which was selected by Moderna in collaboration with investigators from the Vaccine Research Center (VRC) at the National Institute of Allergy and Infectious Diseases (NIAID), a part of the US National Institutes of Health (NIH). Vaccine candidates from the NIH and Moderna Inc, and the one from the Oxford University, have been getting maximum attention as over 100 vaccines are currently under various stages of trial. Shares of Moderna jumped nearly 20 per cent after the US biotech company announced positive interim clinical data for a potential coronavirus vaccine on May 18 as Dow soared over 900 points. Moderna anticipates the dose for the Phase 3 study to be between 25 Aug and 100 Aug and expects Phase 3 trial initiation in July, subject to finalisation of the clinical trial protocol. /IANS