No guarantee any Covid vaccine in development will work: WHO Chief

WHO Chief Tedros Adhanom Ghebreyesus said there is no guarantee any Covid-19 vaccine in 'development will work'. In a virtual address, Tedros also said that almost 200 Covid vaccines are in clinical & pre-clinical testing. “We have no guarantee that any single vaccine in development will work. The more candidates we test, the higher the chance we will have a safe and efficacious vaccine. Almost 200 vaccines for Covid-19 are currently in clinical & pre-clinical testing. The history of vaccine development tells us that some will fail and some will succeed,” said Tedros. Watch the full video for more.