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A study has showed that China’s widely used Sinovac vaccine failed to produce sufficient antibodies to neutralize the omicron variant.
A team at the Department of Microbiology of the University of Hong Kong analyzed serum antibodies from 25 people fully vaccinated with CoronaVac, developed by Sinovac, as well as a separate group of 25 more who had received two doses of the COVID vaccine from Pfizer
PFE,
and its German partner BioNTech
BNTX,
None of the 25 vaccinated with two doses of the Sinovac vaccine showed any neutralizing antibodies against the omicron variant.
Of the Pfizer-BioNTech group, five showed neutralizing ability, though with vaccine efficiency “significantly reduced” to 20% to 24%. Compared with the original COVID strain, neutralizing antibodies against omicron dropped by 36 to 40 times in that group, the study said.
The authors recommend a third dose of COVID-19 vaccines, though they say it remains unclear how effective that will be in enhancing neutralizing responses against omicron. The study’s results have been accepted for publication in the medical journal Clinical Infectious Diseases, and available online as a preprint.
The study could be a worrying early signal for the fight against the omicron variant as Sinovac is one of the most widely used vaccines in the developing world. The vaccine uses an inactivated form of the COVID-19 virus, instead of the mRNA technology used by Pfizer and Moderna
MRNA,
Scientists are still racing to learn how well current vaccines will hold up against the rapidly spreading omicron variant, which was brought the world’s attention by South African scientists in late November.
A large-scale study of omicron in South Africa, also released Tuesday revealed that two doses of the Pfizer and BioNTech vaccine provided 33% protection against infection but 70% protection against hospitalization, the Associated Press reported.
