(Reuters) – China’s Sinovac Biotech said on Friday that final test data from its COVID-19 vaccine from Brazil and Turkey showed that it prevented hospitalization and death in patients with COVID-19, but had a much lower rate of effectiveness in blocking infections.
The trial of 12,396 people found that the CoronaVac vaccine was 100% effective in preventing patients with COVID-19 from being hospitalized or dying and 83.7% effective in avoiding cases that required any medical treatment, but only 50.65% effective in prevent people from becoming infected, according to a statement.
The trials evaluated the efficacy of the two-dose vaccine candidate 14 days after inoculation of the participants, including health professionals who treat patients with COVID-19.
In Turkey, the vaccine was tested in two stages between healthcare professionals and the general population, and it was found to have a 91.25% effectiveness rate in preventing COVID-19 based on an analysis of 29 cases, said the company.
In early January this year, Brazilian researchers reported provisional results from the CoronaVac vaccine trial, showing that it was 50.4% effective in preventing symptomatic infections.
The efficacy rates of other vaccines vary widely by country, an emerging pattern that reflects the impact of new variants.
Among the coronavirus variants currently of most concern to scientists and public health specialists are British, South African and Brazilian, which appear to spread more rapidly than others.
In comparison, the two COVID-19 vaccines currently authorized by Pfizer Inc and partner BioNTech SE and Moderna Inc have proven to be about 95% effective in preventing disease in their main clinical trials. These studies were done in the United States before extensive reports of variants.
Brazil’s national immunization program currently depends on CoronaVac and the vaccine developed by Oxford University and AstraZeneca Plc. Both have been approved for emergency use.
(Reporting by Vishwadha Chander, edited by Peter Henderson and Sonya Hepinstall)