CanSino Biologics Inc’s experimental coronavirus vaccine has an efficacy rate of 65.7% at preventing symptomatic cases based on an analysis from late-stage trials, adding a one-shot candidate to the world’s growing arsenal against Covid-19.
The inoculation co-developed by the Chinese military and the Tianjin-based biotech company proved effective against symptomatic Covid-19, based on a multi-country analysis first posted on Twitter by Faisal Sultan, Pakistan’s health adviser, on Monday. CanSino later forwarded Sultan’s announcement in a statement. The final stage trial included 30,000 participants and was also 90.98% effective in preventing severe disease, Sultan said.
A vaccine needs to afford at least a 50% protection rate to be considered effective, as mandated by the world’s leading drug regulators and the World Health Organization. While CanSino’s data seems at first glance lower than the 95% protection rate provided by shots from Pfizer Inc and Moderna Inc, it requires just one shot, not two.
That means it’s more accurately compared to Johnson & Johnson’s vaccine, the only other single shot that has released final stage testing data. That vaccine was found to be 66% effective in a global trial.
While their efficacy numbers are lower, single-shot vaccines offer some advantages over the cutting-edge mRNA inoculations from Pfizer and Moderna. The mRNA two-dose shots require deep-freeze storage and risk spoiling if thawed too quickly, creating distribution hurdles. CanSino and J&J’s candidates are easier to store and don’t require people to return at a set time for the second jab -- something that’s hard to guarantee especially in developing countries.
“A 70% effective single-dose vaccine may be more valuable than a two-dose regimen with 90% efficacy and greater implementation challenges,” a group of experts advising the World Health Organization on vaccines wrote in an article last month in the New England Journal of Medicine.
Among two-dose regimens, China’s vaccines have fallen behind western and Russian peers. The shot developed by the state-owned China National Biotec Group Co, a unit of Sinopharm, was shown to be 78% effective, while one from Sinovac Biotech Ltd had a 50.38% rate in a trial involving high-risk medical workers. Russia’s Sputnik V showed efficacy of 91.6%, matching the stellar efficacy of the mRNA shots.
Trials for AstraZeneca Plc’s vaccine resulted in an average of 70% from two different dosing regimes.
Efficacy Parade
The parade of efficacy reports has resulted in a steadily growing arsenal of inoculations as drug makers and governments have sped up the vaccine development process to fight the pandemic. CanSino adds another successful candidate from Chinese developers, who have played catch-up with Western rivals in finishing Phase III trials after an early lead in the process.
As richer nations secure the first supplies and the WHO-backed Covax initiative that many developing countries were relying on for vaccines has not yet started, China is filling the void by donating its vaccines to poorer places.
CanSino has agreed to supply 35 million doses to Mexico while Malaysia is in talks to get 3.5 million shots. Pakistan, where one of CanSino’s biggest trials is being conducted, will get 20 million shots. Pakistan’s efficacy at preventing symptomatic cases is 74.8%, Sultan said, adding that a tranche of vaccines had been sent by China’s army to his country’s military.