Uk Vaccine Expert Andrew Pollard

The highly transmissible Delta variant of coronavirus has rendered the prospect of herd immunity, where the majority of a country's population becomes immune to a virus, difficult, the head of the UK's Oxford Vaccine Group has warned.

The highly transmissible Delta variant of coronavirus has rendered the prospect of herd immunity, where the majority of a country's population becomes immune to a virus, difficult, the head of the UK's Oxford Vaccine Group has warned.