THL says that the recommendation is a precautionary measure. At the moment there is no swine flu epidemic in the country that would require urgent vaccination against the virus, it notes.

"Indications of a time link between vaccinations and narcolepsy cases have been seen, but an actual link has not been established. In light of international information, a connection would even seem unlikely," Dr Hanna Nohynek, a special researcher at THL, told YLE on Tuesday.

Exceptions can be made to the THL recommendation if needed. For instance, the vaccine can be given to people travelling to any area experiencing a swine flu epidemic.

Experts to gather

If required, a final decision on a nationwide end to the swine flu vaccination programme will be made by the Ministry of Social Affairs and Health. Such a decision will be taken if the reported cases of narcolepsy are proven to have resulted from the vaccine.

The group coordinating the investigation into the cases is scheduled to meet next Tuesday to make an overall evaluation. It is comprised of experts from THL, the Ministry of Social Affairs and Health, the National Agency for Medicines, the National Supervisory Authority for Welfare and Health Valvira, and representatives of provincial authorities.

According to the THL, the increase in the number of cases of narcolepsy may have been caused by the flu virus, by the vaccine, by the interaction of an infection with the vaccine, or some other factor. It is known that infections can cause narcolepsy.

THL has been notified of 15 cases of narcolepsy, six of which are more clearly associated with the vaccination than are the remainder. Preliminary research into the connection between the vaccine and the cases is expected to take several months. Annually up to 50 cases of narcolepsy are diagnosed in adults in Finland and fewer than 10 in children.

Worldwide, at least 90 million people have received the Pandemrix vaccine in more than 20 countries. However, so far a possible link between the swine flu vaccine and narcolepsy has been reported only in Finland and Sweden.