Paris, May 18 : A Covid-19 vaccine developed by pharmaceutical giants Sanofi and Glaxo Smith Kline (GSK) has shown strong rates of neutralising antibody responses against the infectious Coronavirus disease in the Phase-II trial. The Phase-II trial, which involved 722 adult volunteers from the US and Honduras between 18 to 95 years old, did not raise any safety concerns and also produced a strong immune response across all age groups. It showed 95 per cent to 100 per cent seroconversion following a second injection, while a single jab produced high neutralising antibody levels among people with prior SARS-CoV-2 infection. This suggested the vaccine's strong potential for development as a booster shot. The vaccine also elicited strong neutralising antibody levels that were comparable to those generated by natural infection. The higher levels observed in people between 18 to 59 years old. "Our Phase 2 data confirm the potential of this vaccine to play a role in addressing this ongoing global public health crisis, as we know multiple vaccines will be needed, especially as variants continue to emerge and the need for effective and booster vaccines, which can be stored at normal temperatures, increases," said Thomas Triomphe, Executive Vice President and Global Head of Sanofi Pasteur, in a statement. "These positive data show the potential of this protein-based adjuvanted vaccine candidate in the broader context of the pandemic, including the need to address variants and to provide for booster doses. We believe that this vaccine candidate can make a significant contribution to the ongoing fight against Covid-19," added Roger Connor, President of GSK Vaccines. In December, last year, the Sanofi-GSK faced a major setback after their experimental Covid-19 vaccine did not appear to work well in older adults. The pharma companies, now, aim to start a global pivotal Phase 3 study in the coming weeks. The Phase-III trial is expected to enroll more than 35,000 adult participants from a broad range of countries and will assess the efficacy of two vaccine formulations including the D614 (Wuhan) and B1351 (South African) variants. The French pharma company Sanofi and its British peer GSK aim to produce up to one billion doses in 2021. In addition, the companies also intend to conduct booster studies with various variant formulations in order to assess the ability of a lower dose of the vaccine to generate a strong booster response regardless of the initial vaccine platform received. /IANS