The study will evaluate the efficacy, immunogenicity and safety of the CoronaVac vaccine on children and adolescents aged six months to 17 years, the firms said in a statement.
The trial has been approved by South African drugs regulator SAHPRA, and the first child will be vaccinated at the MeCRU Clinical Research Unit based at the Sefako Makgatho Health Sciences University on Friday.
"The primary objective of the study is to evaluate the efficacy of two doses of CoronaVac against confirmed symptomatic Covid-19 cases in children and adolescents ... efficacy will also be evaluated against hospitalisation and severe Covid-19," Sinovac and Numolux said.
The South African government has said it is considering using the CoronaVac vaccine in its immunisation programme alongside shots developed by Pfizer and Johnson & Johnson which have been administered so far.
BACKGROUNDSinovac COVID-19 vaccine
A real-world study of tens of millions of Chileans who received CoronaVac found it 66% effective against symptomatic COVID-19, 88% against hospitalization, 90% against ICU admissions, and 86% against deaths. In Brazil, after 75% of the population in Serrana, São Paulo, received CoronaVac, preliminary results show deaths fell by 95%, hospitalizations by 86%, and symptomatic cases by 80%. In Indonesia, real world data from 128,290 healthcare workers showed 94% protection against symptomatic infection by the vaccine, beating results in clinical trials.
Phase III results from Turkey published in The Lancet showed an efficacy of 84% based on 10,218 participants in the trials. Phase III results from Brazil previously showed 50.7% efficacy at preventing symptomatic infections and 83.7% effective in preventing mild cases needing treatment. Efficacy against symptomatic infections increased to 62.3% with an interval of 21 days or more between the doses.
CoronaVac is being used in vaccination campaigns in various countries in Asia, South America, Central America, and Eastern Europe. By April 2021, Sinovac had a production capacity of 2 billion doses a year. It is currently being manufactured at several facilities in China, with planned overseas manufacture in Brazil in September 2021 and eventually in Egypt and Hungary.
On 1 June 2021, the World Health Organization validated the vaccine for emergency use. Sinovac has signed purchase agreements for 380 million doses from COVAX. As of July 2021, CoronaVac was the most widely used COVID-19 vaccine in the world, with 943 million doses delivered.
The vaccine is given by intramuscular injection into the deltoid muscle. The initial course consists of two doses. According to the World Health Organization , there is no evidence that a third booster dose dose is needed, but early evidence from Chile suggests it might be. The WHO recommends an interval of 2 to 4 weeks between doses, with data from Chile suggesting that a longer interval provides more robust immunity.