Expert: No coronavirus vaccine before end of 2021 under most optimistic scenario

“Vaccine development is a hugely complicated and expensive process,” he told Sky News, adding that there were multiple stages of human trials involved to make sure it was safe and effective.

“On top of that, you need to make sure in this kind of situation of your manufacturing capacity, which essentially is sufficient for the whole world.”

"Having a one-and-a-half to two year timeline to get that done is nothing short of a miracle.”

Penttinen is the head of the ECDC’s Influenza and other Respiratory Viruses Programme.