Sinopharm, Sinovac Shots Protective in Guangdong Outbreak, Chinese Researchers Say
(Bloomberg) -- China’s inactivated vaccines maintained their protective power during a recent outbreak of Covid-19 in the southern Chinese province of Guangdong, providing real world evidence about their ability to stave off the highly infectious delta variant.
The immunizations from state-owned Sinopharm and Sinovac Biotech Ltd. had a combined effectiveness of 70% against pneumonia caused by Covid and completely protected against severe disease caused by the delta variant, according to a pre-print study from researchers with the Guangdong Provincial Center for Disease Control and Prevention. The paper hasn’t yet been reviewed by outside experts.
The paper tracked more than 10,000 people, including those infected and their close contacts during the outbreak that started in late-May and ended in mid-June. A total of 167 people contracted the virus. About one in eight of those in the study were fully vaccinated, mostly with shots from Sinopharm and Sinovac, and just over half were unvaccinated. The remainder had received at least one shot but came into close contact with someone who was infected before they had time to fully build up their immunity.
The research is the first real world examination of the potency of Chinese shots against the delta strain that is driving a resurgence of disease around the world. It comes amid questions about the effectiveness of the Chinese vaccines compared to those made elsewhere, as evidence emerges that some rival shots have less potency when trying to ward off delta infections.
Both the Sinopharm and Sinovac vaccines have been widely used across China and much of the developing world. Millions more doses will be supplied globally through the Covax program backed by the World Health Organization to countries struggling to get enough shots to immunize their people.
The study evaluated the ability of the Chinese shots to prevent fully vaccinated people from developing pneumonia or severe disease caused by Covid. The design makes it difficult to directly compare them to western shots, such as the mRNA vaccine from Pfizer Inc. or the viral vector immunization from AstraZeneca Plc. Those inoculations were found to be 88% and 67% effective against symptomatic infections caused by the delta variant in an English study, and all appear to be highly effective against severe disease.
The two inactivated Sinopharm shots were originally found to be 78% and 73% effective against symptomatic disease in pivotal trials earlier in the outbreak, before delta was circulating. The Sinovac shot’s efficacy ranged from a little over 50% to 83.5% across a number of testing sites in late-stage trials.
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