BY: GRADY MCGREGOR

China may have a viable one-shot COVID-19 vaccine.

On Monday, Pakistan Health Minister Faisal Sultan announced on Twitter that Chinese vaccine maker Cansino Biologic’s COVID-19 vaccine was 65.7% effective in preventing symptomatic cases of the virus and 90.1% effective in preventing severe diseases.

Sultan said the figure was based on a multiple-country analysis of Cansino’s Phase III clinical trials, but the Pakistani subset with 30,000 participants showed slightly stronger figures of 74.8% protection against symptomatic cases and 100% protection against severe infections. In addition to Pakistan, Cansino has tested its vaccine in Mexico, Chile, and Argentina.

Neither the Pakistani government nor Cansino released further data or comment on the efficacy figure, meaning Cansino joins other Chinese vaccine makers Sinopharm and Sinovac in publishing little data beyond headline efficacy figures. Cansino did not respond to Fortune’s request for comment.

Cansino, which coproduced its vaccine with the Chinese military, had once been the leader in the global COVID-19 vaccine race, launching the world’s first clinical study of its vaccine in mid-March.

Cansino was also the first to publish peer-reviewed data on its Phase I clinical trial in May.

The early trials, however, showed that Cansino’s vaccine induced only a limited immune response among participants that was overshadowed by the blockbuster results from Pfizer and Moderna weeks later.

After surging ahead in the vaccine race, foreign vaccine makers like Pfizer and Moderna also beat Cansino in completing Phase III clinical trials, gaining governmental approvals, and rolling out their vaccines.

Cansino also fell behind its Chinese counterparts Sinovac and Sinopharm, which are now distributing hundreds of millions of doses across at least a dozen foreign countries. Sinopharm says its vaccine is 79% effective, while Sinovac’s partners have announced figures saying the vaccine is between 50% and 90% effective.

Cansino’s shot is based on similar viral-vector vaccine technology that Johnson & Johnson is using for its own one-shot vaccine. Cansino’s 65% efficacy rate also appears on par with Johnson & Johnson’s 66% figure. Cansino’s 65% efficacy figure would pass the World Health Organization’s recommended threshold of 50%, but it still lags behind the 94% and 95% figures posted by Moderna and Pfizer, respectively.

Like the J&J single-dose vaccine, Cansino may have distinct advantages in distributing its jabs to poor and middle-income countries.

Unlike mRNA vaccines from Pfizer and Moderna, Cansino’s vaccine does not require subzero storage; it can be transported in less expensive supply-chain networks at normal refrigerated temperatures (2 to 8 degrees Celsius). Its administration in a single dose could boost efforts to distribute vaccines to more rural areas, where it may be difficult to send supplies and set up follow-up appointments.

Cansino’s vaccine has not been officially approved in Pakistan or any other country, but it has been distributed to members of China’s military and to other high-risk population groups in China on an emergency basis since at least June 2020.

Cansino’s vaccine may soon be rolled out in several foreign countries. Mexico, for example, said this week that Cansino submitted paperwork for approval. Cansino and the makers of Russia’s Sputnik vaccine are also reportedly involved in a mixed trial to see if receiving both vaccines offers enhanced protection against COVID-19.

In August, Cansino said it had an annual production capacity of between 100 million and 200 million doses.

In November 2020, Cansino founder Yu Xuefeng told Fortune about the potential benefits of having a viable one-shot COVID-19 vaccine.

“In the pandemic environment, what you need is a vaccine that can quickly provide protection,” Yu said. “If we can make a single dose work, it will stop the spread of the virus.”