Switzerland on Monday approved Moderna's Covid-19 vaccine for youngsters aged between 12 and 17 years old, weeks after EU regulators authorised the drug for the same age group.

The Swissmedic regulatory authority, which has already approved the Pfizer-BioNTech jab for over-12s, said results from an ongoing study showed Moderna had 93 percent efficacy in the young age group.

"The vaccine produced a similar immune response... in this study compared to young adults aged 18 to 25 years," the regulator said.

Switzerland, which is not in the European Union, has its own regulatory process and was the first country in continental Europe to start using the Pfizer-BioNTech jab.

The country has doled out more than 9.1 million doses and nearly 49.2 percent of the population of 8.6 million are now fully vaccinated.

However, take-up has slowed in recent weeks. Nearly 2.5 million doses were administered in June but fewer than 1.4 million in July.

The virus has killed 10,354 people in Switzerland and 723,907 positive tests have been registered.

Moderna's Covid-19 jab is used in 48 countries, behind AstraZeneca (161), Pfizer-BioNTech (88) and Sinopharm (49), according to an AFP count.