China's Sinovac Covid-19 vaccine candidate appears safe, weaker in elderly
Health officials have been concerned about whether experimental vaccines could safely protect the elderly, whose immune systems usually react less robustly to vaccines.
A volunteer receives an injection in a human clinical trial for a potential vaccine against the novel coronavirus, at the Baragwanath hospital in Soweto, South Africa, June 24, 2020(photo credit: REUTERS/SIPHIWE SIBEKO)ByREUTERS
