China’s Sinovac claimed 94% effectiveness of the third dose of its Covid-19 vaccine against the omicron variant of the coronavirus pandemic.

Among 48 individuals who received three doses of CoronaVac, 45 or 94% tested positive for neutralizing antibodies, the report of drugmaker Nikkei Asia indicated.

In the report, Forbes noted Sinovac also stated that seven out of 20 people who had received two shots of its CoronaVac vaccine tested positive for neutralizing antibodies—which the vaccine maker says is an efficacy rate of 35%.

Sinovac’s study was based on two omicron samples collected from Hong Kong and the company is conducting further studies to offer a more comprehensive evaluation, the report added.

Sinovac’s CoronaVac is one of the most widely used Covid-19 vaccines across the world and is one of the two Chinese made shots that have received emergency use approval from the WHO.

The response of Sinovac comes after a study published by the University of Hong Kong raised concerns about the widely used vaccine’s effectiveness against the rapidly spreading omicron variant. 

The study examined the serum from 25 people who received two doses of CoronoVac and found that none of them contained detectable antibodies that neutralized omicron.

The total number of doses of the Sinovac vaccine that China has distributed around the world reached over 808 million, according to data compiled by Beijing based Bridge Consulting.