The level of efficacy provided by the Sinopharm Covid-19 vaccine is compatible with that required by the World Health Organisation, the chairman of a WHO panel said.
Alejandro Cravioto’s comments were based on data provided by the Chinese manufacturer in a closed-door meeting to WHO experts last week.
The meeting also discussed the efficacy of Sinovac, another Chinese-made vaccine, against Covid-19.
Dr Cravioto said the information shared during the Strategic Advisory Group of Experts meeting “clearly indicates that they have levels of efficacy that would be compatible with the requirements that WHO has asked for this vaccine”.
“That means about 50 per cent [efficacy] and preferably close to, or above 70 per cent and of course, they have all the safety data to show that this vaccine would cause no harm in humans when used,” he said.
The vaccines have not yet received WHO approval.
WHO spokeswoman Margaret Harris said last month that Sinopharm and Sinovac vaccines could receive WHO emergency listing "quite soon".
A decision is expected by the end of April.
The Sinopharm vaccine factory in China
Dr Cravioto said the vaccines would first require emergency use listing from the WHO, or from a body considered by the organisation as a “stringent regulatory authority”, before Sage experts can make recommendations about their use.
“The 50 per cent efficacy threshold set for Covid-19 vaccines is because Covid-19 was deemed such a severe disease, that if a vaccine is only 50 per cent effective, it’s still worth using,” said Dr Lee Hampton, a paediatrician and medical epidemiologist with Gavi, the Vaccine Alliance, in an online explainer by WHO about Covid-19 vaccine efficacy.
A study in Brazil showed Sinovac's vaccine to be 50.4 per cent effective.
Sinopharm, the most widely available vaccine in the UAE, was found to be 86 per cent effective in preventing infections in local trials.
The manufacturer later revised this to 79 per cent, after studies in several countries.
Emirati officials, however, said Sinopharm had proved to be 100 per cent effective against the development of serious disease – an important metric.
Dr Nawal Al Kaabi, chairwoman of the National Covid-19 Clinical Management Committee, told a conference on the Covid-19 response in the UAE that there were no critical care admissions or deaths among those who had been vaccinated in Abu Dhabi.
People who were infected after taking both doses of the vaccine were mostly asymptomatic or presented only mild symptoms, she said.
Efficacy of other vaccines
The Pfizer-BioNTech vaccine, one of two in use against Covid-19 using new mRNA technology, surprised many scientists by offering 95 per cent protection against the virus.
But it does not prevent severe disease completely.
In the Phase 3 Pfizer trial, there were 10 severe cases of Covid-19, one of which occurred in the vaccine group.
The vaccine has, however, been extremely effective in the real world, with at least 97 per cent protection against symptomatic Covid-19 cases, admission to hospital, severe and critical cases and deaths in Israel.
Other vaccines found to protect against severe Covid-19 complications include AstraZeneca and Moderna, which both offered 100 per cent protection against severe disease in trials.
Sinopharm has not yet released detailed Phase 3 data on the vaccine’s efficacy in a peer-reviewed journal, like other manufacturers such as Pfizer or Sputnik.