The head of WHO Europe said this week that such jabs -- given low vaccination coverage in poorer parts of the world -- should not be seen as “luxury boosters”.
France began giving booster jabs of COVID-19 vaccines on Wednesday.
The recipients will be those over the age of 65 and people with underlying health conditions, providing a minimum of six months has passed since they got fully vaccinated with the Pfizer or Moderna vaccine.
Those who received the single-dose Johnson & Johnson jab can get a booster shot of Pfizer or Moderna at least four weeks after they first got vaccinated.
France's health ministry said about 18 million people are estimated to be eligible for the booster shot.
The government followed the recommendations of the country's health authority, the HAS, which said last month that “recent studies suggest a fall in the vaccine’s effectiveness, especially with the delta variant”.
The elderly and people with underlying health conditions are the most affected by the drop over time, the HAS said.
The booster shot was already available in France for some particularly vulnerable people, like transplant recipients and others with weakened immune systems.
The French government so far has made no decision regarding the potential extension of the campaign to the whole population.
France has been facing high numbers of confirmed infections since July, with a slight decrease in recent weeks — from over 23,000 per day around mid-August to 17,000 now. But many fear a reverse of the trend as children will go back to school after the summer holidays on Thursday.
Almost 44 million people, or 65.6% of the French population, are fully vaccinated.
France's decision to launch its booster campaign comes as the European Medicines Agency said it is reviewing data to see if booster shots are needed.
In Germany, authorities in Berlin, the capital, started on Wednesday offering booster shots to residents of elderly care homes. Several other German states have already begun offering boosters to vulnerable people.
Israel has expanded this week its coronavirus booster shot program to include anyone over 12 — the latest phase of a booster program that began in July with Israelis over 60.
US health officials announced last month plans to dispense booster shots to all Americans. The campaign is expected to start by the end of September.
The head of the World Health Organization’s European branch, Dr Hans Kluge, said this week he agrees with the top US infectious diseases expert that a third dose of coronavirus vaccines can help protect the most vulnerable people, and it shouldn’t be seen as a “luxury booster”.