LONDON (REUTERS) - The world will need more than one Covid-19 vaccine so drug companies must partner in the race to develop the weapons to fight the novel coronavirus, GlaxoSmithKline chief executive officer Emma Walmsley said on Wednesday (April 15).

GlaxoSmithKline Plc and Sanofi SA said on Tuesday that they would develop a vaccine to fight the fast-spreading coronavirus.

The drugmakers said they expect to start clinical trials for the vaccine in the second half of this year. If successful, the vaccine would be available in the second half of 2021.

Ms Walmsley said GSK's partnership with Sanofi brings scale to the attempt to get a Covid-19 vaccine but that there was still an enormous amount of work to do.

"The world's going to definitely need more than one vaccine when you think about demand in this hugely challenged global health crisis," she told BBC Radio.

The adjuvanted vaccine will be developed by combining Sanofi's S-protein Covid-19 antigen and GSK's pandemic adjuvant technology.

"It normally takes a decade, sometimes even more, to develop a vaccine but obviously we are in an unprecedented situation, the need is incredibly urgent. We are partnering with regulators to try and go as fast as we safely can," she said.