More vaccines enter clinical trials

China has about a dozen COVID-19 vaccines that have entered clinical trials, in addition to the four vaccines already on the market, Shao Yiming, chief expert at the Chinese Center for Disease Control and Prevention, told a news briefing on Wednesday.

He said an attenuated influenza virus vector vaccine has completed early and mid-stage clinical trials and has demonstrated excellent safety and ability to cause an immune response. Research on mRNA and DNA-based vaccines has also shown promise in preclinical studies and has entered mid-stage clinical trials.

The government laid out five technical routes to develop vaccines early in the COVID-19 outbreak, with three inactivated vaccines and one adenovirus vector vaccine already marketed and a recombinant protein vaccine approved for emergency use.

The remaining two technical routes under research are mRNA and DNA-based vaccines and the attenuated influenza virus vector vaccine.

Shao said in addition to technological innovation, innovative mechanisms are also needed to accelerate the development of vaccines.

As the pandemic at home is well under control, China needs to cooperate with other countries to conduct late-stage clinical trials. However, as the situation is still grim globally, other countries face public health pressure and ethical issues when setting up control groups using a placebo.

"Everybody wants to be vaccinated, instead of taking a placebo," he said.

Shao said some innovation can be considered, such as evaluating the effectiveness of vaccines via surrogate end points or real-world studies, in order to accelerate their entry into the market.