An employee holds a vial containing Sinovac Biotech's vaccine against COVID-19 at the Butantan biomedical production centre in Sao Paulo. [Source: Aljazeera]

A coronavirus vaccine developed by China’s Sinovac Biotech was found to be just 50.4 percent effective at preventing symptomatic infections of COVID-19 in a Brazilian trial.

This is barely enough for regulatory approval and well below the rate announced last week.

The latest results are a substantial disappointment for Brazil, as the Chinese vaccine is one of two that the federal government has lined up to begin immunization during the second wave of the world’s second-deadliest COVID-19 outbreak.