‘Inactivated’ vaccines use a heat or chemically-treated version of the virus, and this method has been used to produce certain Polio and flu vaccines. It requires the right amount of heat or chemical to destroy infectivity, as too much could change the virus proteins, rendering the vaccine ineffective. There are Chinese inactivated vaccine candidates under development, including the State-owned SINOPHARM’s ‘Vero-Cell’, in Phase Three trials and expected to complete in summer 2021.