Germany, France and Israel will go ahead with plans to administer COVID-19 vaccine boosters, disregarding an appeal by the World Health Organization to hold off until more people are vaccinated around the world.

The decision to press ahead with booster shots despite the WHO's strongest statement yet highlights the huge inequities in responses to the pandemic as richer nations ramp up programs to protect citizens from the more infectious delta variant.

French President Emmanuel Macron said France was working on rolling out third doses to older citizens and the vulnerable from September.