US vaccine boost put down to Covid Delta variant

The spread of the Delta variant of Covid-19 in parts of the US is encouraging more people to get vaccinated, Dr Marcus Plescia, chief medical officer, at the Association of State and Territorial Health Officials, has said.

He told BBC World News the past week had seen a slight increase in vaccinations.

"We would like to see much more but we are seeing it start to trend up a little bit and we are hearing from people that this has gotten their attention," Dr Plescia said.

There had been serious increases in infections in states in the South East and mid-West, he added.

America's top infectious-disease expert, Dr Anthony Fauci, earlier said the variant, first identified in India, was driving the spike in areas with low vaccination rates, adding health officials were considering revising mask guidance for vaccinated Americans - to curb cases.