Livzon’s vaccine, if rolled out to the public, would widen booster options for China’s 1.4 billion population, of which 90% have been vaccinated and nearly 60% received a booster dose.

Most people in China have been injected with inactivated vaccines from Sinovac or Sinopharm for primary vaccination, among seven domestically developed shots the country approved for use between 2020 and 2021.

Data showed that other vaccines, ranging from foreign mRNA products produced by Pfizer-BioNTech or Moderna to domestic non-inactivated candidates, elicited higher antibody readings against the Omicron variant as a mix-and-match booster compared with using a third Sinovac or Sinopharm dose.

Livzon’s protein-based vaccine, adopting a different technology than Sinovac and Sinopharm’s products, were among the two products Chinese officials said have recently been cleared for use.

The other one has not been formally identified.

The regimen of one Livzon booster after two doses of inactivated vaccines had an efficacy of 61.35%, Livzon said in February, citing preliminary data from a trial involving more than 10,000 participants and 110 cases, without providing details.

The combination had an efficacy of 60.81% against Omicron, based on calculations involving 63 cases infected with the variant, a Livzon executive said today, without specifying the severity of those cases, or which subvariants of Omicron the participants had contracted.

The company is working on bivalent or multivalent vaccine candidates, which include designs targeting the BA.5 subvariant of Omicron, after animal test data showed a candidate updated for BA.5 solely did not elicit broad neutralisation across variants, Yang Jiaming, deputy general manager at Livzon’s vaccine unit, told an event.

China currently only allows one booster dose following primary vaccination.

It has yet to approve any foreign-made doses.