China's mRNA vaccine triggers immune response in 95% of recipients in first stage of trial

A medical worker administering a Covid-19 booster shot in Wuhan on Nov 25, 2021.

BEIJING (CAIXIN GLOBAL) - China's first home-grown Covid-19 vaccine using mRNA technology can trigger an immune response in as many as 95 per cent of recipients with no severe adverse reaction reported, according to data from the first stage of clinical trials.

The vaccine, known as ARCoV, is being jointly developed by Walvax Biotechnology, Suzhou Abogen Bioscience and the PLA Academy of Military Science.

A phase one clinical trial of the vaccine was conducted at Shulan Hospital in Hangzhou, eastern China's Zhejiang province, to assess the preliminary safety, tolerability and immunogenicity of the shot, according to a report published on Monday (Jan 24) in The Lancet Microbe.

Between Oct 30 and Dec 2, 2020, the trial recruited 120 healthy adults aged 18 to 59 years to be randomly assigned to receive an injection of a vaccine or placebo.

Subjects were divided into groups taking different doses of the vaccine ranging between five micrograms (mcg) and 25mcg. One hundred and eighteen participants received two doses 28 days apart.

Neutralising antibodies were found among 80 per cent to 95 per cent of the participants who took two doses of the vaccine, varying with the dosage they received.

The group receiving a 20mcg injection showed the highest, a 95 per cent antibody-positive rate, according to the report.

No severe adverse event was reported among participants, but most of them did show mild reactions.

Among those who took 15mcg doses, 70 per cent reported pain at the injection site and 90 per cent had fever.

The mRNA technology used delivers a bit of genetic code to cells, teaching the cells to make a protein that triggers an immune response to the coronavirus.

Currently, two mRNA Covid-19 vaccines - one developed by Pfizer-BioNTech and another by Moderna - are in use globally.

Those vaccines outperformed others in clinical trials and are among the most administered Covid-19 shots in the world. The Chinese mainland has not yet approved any mRNA vaccine for public use.

ARCoV was approved by China's drug regulator in June to start clinical trials, making it the front runner among home-grown mRNA vaccines.

The vaccine is in phase three trials overseas, including Mexico, Indonesia and Nepal. But no data from the phase two and three studies has been released.

Researchers also studied using the vaccine as a booster shot for Chinese people, most of whom have received two shots of an inactivated-virus vaccine.

In addition to ARCoV, alternative mRNA vaccines developed by Chinese biotech companies, including Stemirna Therapeutics and Zhuhai Lifanda Biotechnology, are also undergoing clinical trials.

In December, construction of a production facility for ARCoV started in south-west China's Yunnan province. The project is set to start operation in eight months with an initial capacity of 120 million doses a year, according to Abogen.

Join ST's Telegram channel and get the latest breaking news delivered to you.