HANOI, June 8 — Vietnam's capital, Hanoi, is considering injecting the fourth dose of Covid-19 vaccines to vulnerable adults or those whose jobs put them at high risk of exposure to the virus, starting this month.

PARIS, March 13 — France will start offering a fourth Covid-19 vaccination shot to people over 80 years old who have received their booster dose on Monday, French Prime Minister Jean Castex told daily Le Parisien in an interview published on Saturday.