Sinopharm's two COVID-19 shots effective, study says
Two COVID-19 vaccines from China's Sinopharm showed more than 70 percent efficacy against symptomatic cases with rare serious adverse effects reported, according to the world's first published phase-three study results of inactivated COVID-19 vaccines.
A vaccine developed by a Wuhan-based subsidiary of Sinopharm was 72.8 percent effective against symptomatic COVID-19 at least two weeks after second injection, based on interim results, the peer-reviewed study published in the Journal of the American Medical Association showed on Wednesday. Another vaccine developed by a Beijing-based institute linked to Sinopharm, which this month obtained emergency use approval by the World Health Organization, showed a 78.1 percent efficacy, the paper said.
The randomized, double-blind and placebo-controlled trials were designed by the Wuhan and Beijing institutes. Study enrollment began on July 16, 2020. Data sets used in the study were locked on December 31, 2020.
The virus strains in the study were isolated from two patients in Wuhan's designated coronavirus-treating Jinyintan Hospital and separately used to develop the two inactivated vaccines.
The readings were based on calculations over 142 symptomatic cases in a trial involving more than 40,000 participants, with 26 injected with the Wuhan unit's vaccine and 21 with the Beijing unit's shot. The vaccination procedure required two injections with an interval of 21 days. "There were only two severe cases of COVID-19 among participants, so conclusions about prevention of severe cases cannot be made," the paper said. "The study could not address the question of whether the ... vaccines prevent against asymptomatic infection, which requires formal study-wide surveillance via virologic and serologic tests," it said.
The trial, conducted in countries including the United Arab Emirates and Bahrain, did not recruit pregnant women and people under 18, while data was insufficient for the elderly and those with chronic diseases.
