Several months after a curious link was observed between the GlaxoSmithKline pandemic flu vaccine known as Pandremix and unexplained cases of narcolepsy emerged in Finland and Sweden, the European Medicines Agency has decided to restrict usage.
Specifically, those younger than 20 years old should use Pandemrix only in the absence of seasonal trivalent flu vaccines, and if immunization against H1N1 swine flu is still needed. An example would be those at risk of complications from infection, according to the EMA (read here). However, the EMA notes that, for now, the benefits continue to outweigh the risks.
Over 31 million doses of Pandemrix have been administered worldwide in 47 countries, according to Glaxo. And a total of 335 cases of narcolepsy in people vaccinated with Pandemrix have been reported to the drugmaker as of July 6, with 68 percent of the cases originating in Finland and Sweden. The earlier reports prompted the World Health Organization to push for further review (read this).
In reaching its decision, the EMA's Committee for Medicinal Products for Human Use reviewed preliminary results of epidemiological studies conducted out in Finland and Sweden, an analysis of safety surveillance data performed in several European Union countries and case reports from across the European Union.
The results show a six- to 13-fold increased risk of narcolepsy compared with unvaccinated children and adolescents in those countries. This corresponds to an additional three to seven cases in every 100,000 vaccinated subjects. This risk increase has not been found in those older than 20, and while a similar risk has not been confirmed in other countries, the EMA says it cannot be ruled out either.
In response, Glaxo says in a statement that further info from ongoing studies, including the final data from an epidemiological study in Europe and another in Canada that is being supported by Glaxo, is "still needed in order to gain additional insight into the cause of the reported cases of narcolepsy." The drugmaker maintains it will conduct more research to any "potential association." The EMA agreed that further research is needed.
sleeping pic thx to dirty s on flickr