Switzerland on Friday restricted the use of British drugs group GlaxoSmithKline's swine flu vaccine Pandemrix, excluding pregnant women, minors and people over the age of 60.
The regulatory authority Swissmedic said it has received data on the vaccine for adults, but not for pregnant women and very little data for children.
"For this reason, Swissmedic has not yet authorised the administration of Pandemrix to pregnant women, children under the age of 18 and adults over 60," the regulator said in a statement.
However, it said one of two vaccines produced by Swiss pharmaceutical giant Novartis was safe to be used by both children and adults.
The vaccine Focetria was already approved by the European Medicines Agency before an authorisation application was filed in Switzerland.
Swissmedic therefore "based its decision largely on the EMEA authorisation," said the regulator.
"In accordance with this, Focetria is recommended for use in adults and children over six months old," it said.
As for usage by pregnant women, Swissmedic left it to doctors to weigh up the advantages and disadvantages of the vaccination.
The regulator added that it was still examining a second Novartis vaccine, Celtura.
Countries in the northern hemisphere are in the midst of rolling out vaccinations programmes, in preparation for the coming winter.
Nearly 5,000 people have died from swine flu infections since the A(H1N1) virus was uncovered in April, according to data issued by the World Health Organisation last week.