China has witnessed 21 COVID-19 vaccines enter clinical trials, an official with the National Health Commission said Sunday.

So far, four COVID-19 vaccines have been granted conditional marketing approval and three have been authorized for emergency use within the country, according to Zeng Yixin, deputy head of the NHC.

A total of eight COVID-19 vaccines have been approved for phase III clinical trial overseas, and one messenger RNA (mRNA) COVID-19 vaccine met the ethical requirements for phase III clinical trial overseas, Zeng said.

He also said the clinical trials of China-developed nasal spray and inhaled COVID-19 vaccines are currently underway.

The nasal spray has been selected as one of China’s vaccine technologies to combat COVID-19 in the very beginning, Zeng said.

Medical experts will study the safety and effectiveness of the tested vaccines after completing the collection of clinical trial data, he added.