BEIJING -- China has strengthened international cooperation in the research and development of vaccines against the novel coronavirus disease (COVID-19), according to an official Thursday.

Vaccines are key to the fight against the epidemic and it is the right choice to carry out international cooperation as vaccine development is difficult and faces many uncertainties, said Xu Nanping, vice minister of science and technology, at a press conference.

China shared the complete genome sequence of the novel coronavirus with the world once it had been identified, hoping many countries could carry out vaccine research and development at an earlier date, Xu said.

China has adopted five technological approaches in vaccine development and the recombinant adenovirus vector vaccine started its clinical trial on March 16.

All the five approaches are open for international cooperation, which is already underway, the official said.

Some Chinese companies are cooperating with their international counterparts in different approaches to vaccine development. A Chinese company is working with Inovio in the United States on a DNA vaccine; a Chinese company is cooperating with German pharmaceutical company BioNTech on an mRNA vaccine and a Chinese company is working with British pharmaceutical company GlaxoSmithKline (GSK) on a recombinant protein vaccine.

Besides these examples, more international cooperation is on the way, Xu said, adding that China's vaccine development pools global strength and will be shared globally.