CanSino Biologics Inc’s (CanSinoBIO) COVID-19 vaccine showed 65.7 percent efficacy in preventing symptomatic cases, and a 90.98 percent success rate in stopping severe disease in an interim analysis of global trials, Pakistan’s health minister said on Monday.
The positive data moves the vaccine, jointly developed by a research institute affiliated with the Chinese military, a step closer to becoming China’s third successful shot for the disease.
Although COVID-19 vaccines from Chinese developers have shown lower protection rates than some Western products, and no detailed study results are publicly available yet, they have already been approved in several developing countries battling a surge in coronavirus infections.
The CanSinoBIO vaccine is being tested in Pakistan, Mexico, Russia, Argentina and Chile, according to clinical trial registration data, and the company has supply deals with some of those countries, including Mexico.
In Pakistan, health minister Faisal Sultan had said that the country could receive “in the range of tens of millions” of the vaccine under an agreement with the Chinese firm.
The efficacy of the shot is based on analysis of 30,000 participants and 101 confirmed cases of COVID-19, the minister said on Twitter, quoting data from an independent data monitoring committee.
No serious safety concerns have been raised in the study, he said.
In the Pakistani subset, efficacy of the CanSinoBIO vaccine at preventing symptomatic cases was 74.8 percent and 100 percent at preventing severe disease, Sultan added.
CanSinoBIO was not immediately available for comment.
While the vaccine’s protection rate trails the more than 90 percent efficacy of shots developed by Pfizer Inc and its partner BioNTech SE and Moderna Inc, its single dose regimen and normal refrigerator storage requirement could make it a favorable option for many countries.
CanSinoBIO’s vaccine - which was approved for use in the country’s military last year and has since been given to at least 40,000-50,000 people - uses a modified common cold virus known as adenovirus type-5 (Ad5) to carry genetic material from the coronavirus protein into the body.
However, researchers in an early and mid-stage trial report expressed concern that the vaccine may not work in those previously exposed to Ad5, as the pre-existing antibody against the common cold virus could weaken the vaccine-triggered immune response.
CanSinoBIO is also testing a two-dose regimen of the vaccine in China including on participants aged between 6-17 and older than 55.
Shots from Chinese companies Sinovac and state-backed Sinopharm have shown efficacy of between 50 percent and 91 percent.
The three firms have applied to join the global vaccine sharing scheme COVAX for approval and China plans to provide 10 million doses to the initiative, which is backed by the World Health Organization and GAVI vaccine alliance.