China’s Covid vaccine is only 50.4 per cent effective, Brazilian researchers have found, just days after they announced results of 78 per cent from their late-stage trials.
The Brazilian Butantan biomedical centre announced last week the Sinovac Biotech jab had proved 78.4 per cent effective against ‘mild to severe’ cases which required treatment.
But it has now been revealed their results did not include ‘very mild’ infections from those who had received the vaccine but did not need medical assistance.
With this data included, the success rate has now dropped to 50.4 per cent, barely sufficient for the 50 per cent minimum for regulatory approval.
It is also well below the 70 per cent recommended by the Chinese government and the World Health Organisation.
The news is a major disappointment for Brazil, as the Chinese vaccine is one of two that the federal government had lined up to administer during their deadly Covid surge.
Many have criticised the Butantan biomedical centre for releasing partial data just days ago that generated unrealistic expectations.
The results came from a trial of 13,000 people in Brazil in the most advanced final phase of testing.
The trial saw 220 people infected of which 160 were in the placebo group and 60 received the vaccine.