One of the complications that makes developing a vaccination against coronavirus so challenging is that the virus itself is constantly mutating.
In China, where the first cases of Covid-19 were reported, a new set of symptoms has emerged. Patients in Jilin and Heilongjiang provinces have been taking much longer to recover than the early cases in Wuhan, according to a senior member of the National Health Commission expert group.
Qiu Haibo told national broadcaster CCTV that the latest batch of patients have not been displaying high temperatures and the damage from the illness was focused on their lungs.
They also appear to be incubating the virus for much longer than the first wave of cases. Qiu says that this longer incubation period