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Chinese mRNA vaccine may fall short of Pfizer, Moderna shots

Residents wearing face masks to help curb the spread of the coronavirus line up to receive booster shots against COVID-19 at a vaccination site in Beijing, Wednesday, Nov. 10, 2021.Andy Wong/Associated Press

(Bloomberg) -- A vaccine being developed in China using messenger RNA, the new technology that has become the backbone for immunizing much of the world, may fall short of the benefits generated by shots from Pfizer Inc., BioNTech SE and Moderna Inc.

The first published study of the experimental vaccine from Walvax Biotechnology Co., Suzhou Abogen Biosciences Co. and the Chinese military generated twice the level of neutralizing antibodies seen in people who had recovered from a COVID-19 infection, though only at an intermediate dose. People given slightly more or slightly less produced fewer of the protective antibodies than those who recovered from an earlier infection, the study found.

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The trial of the vaccine known as ARCoV involving 120 volunteers was published in the journal Lancet Microbe. Six of the 20 people getting the best dose, or 85%, developed a fever. There were no serious complications in the trial, which is from the first of three stages needed to get approval.

Because the vaccine only generated more antibodies compared to previous infection at a precise dose, it may be difficult in the real world to administer the exact amount and reap the full benefit, said Mia He, an analyst with Bloomberg Intelligence. Side effects may also be an issue, with the vaccine causing more fevers than rival shots that are already on the market, she said.

The Chinese shot may trigger more inflammation or damage to the circulatory system, as seen in the study with a transient drop in infection-fighting white blood cells among participants, she said.

Overall, the vaccine shows some promise, but more results are needed, He said. “We will keep cautiously positive on this domestic vaccine candidate,” she said.

While still early, the data isn’t encouraging for China’s ambitions to develop its own highly effective mRNA shot to stop COVID-19 after its first generation of homegrown vaccines were shown to be less powerful than western ones. China’s government also appears unwilling to green-light western mRNA vaccines for domestic use: an application from Shanghai Fosun Pharmaceutical Group Co. to distribute the BioNTech shot locally has been stalled for several months.

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The immunization appeared safe at all doses, the main goal of the trial, and the results supported additional testing, the researchers said. A definitive study from the final round of testing is already underway.

A 2020 trial of Pfizer’s shot showed it generated 3.8 times more neutralizing antibodies than an infection with COVID-19, though it’s difficult to compare results across studies and it’s not clear which strains of the virus were being used.

Only a few people in the Walvax trial developed neutralizing antibodies against the virus after one shot, though everyone had a strong immune reaction after a second injection that was given 28 days later, said the researchers led by Lan-Juan Li from Zhejiang University School of Medicine in Hangzhou. The vaccine also benefits from the fact that it is stable, making it possible to transport and store it under refrigerated conditions, they said.