25 Aug 2010
The Finnish National Institute for Health and Welfare (THL) recommends that vaccination with Pandemrix vaccine is discontinued until an explanation is found for the observed rise in cases of narcolepsy among children and adolescents. THL’s recommendation is based on a proposal from the Finnish National Advisory Committee on Vaccines. The Committee convened on Tuesday 24 August 2010 to consider the matter.
The discontinuation of vaccinations is a safety measure put in place until the matter can be fully investigated. At present there is no swine flu epidemic, so there is no immediate need for swine flu vaccinations in Finland. Moreover, a large part of the Finnish population already has some protection from swine flu as a result of vaccination or from having had swine flu. The vaccine may still be used upon consideration in individual cases, for instance for people travelling to areas where an epidemic is in progress.
A number of different reasons may be behind the observed rise in the incidence of narcolepsy: A(H1N1) infection, vaccination, a compound effect of infection and vaccination, or some other factor entirely. Infections in general are known to cause narcolepsy.
So far, the THL register for adverse events following immunization (AEFI) has received reports of six cases where narcolepsy has followed vaccination. The number is consistent with the annual incidence of narcolepsy under normal circumstances. However, in addition to the above, AEFI reports have not yet been submitted for a further nine possible cases. The symptoms of all the children with narcolepsy started at the end of 2009 and beginning of 2010.
So far, at least 90 million people across the world have had the Pandemrix swine flu vaccine. Children account for more than 4 million of those vaccinated. In Europe alone, the Pandemrix vaccine has been given to at least 30 million people. According to the European Medicines Agency (EMA), no major safety concerns had emerged by the beginning of August. In August, Sweden reported six cases of narcolepsy that showed a temporal association with the Pandemrix vaccinations.
In May, THL received one AEFI report, in which symptoms of narcolepsy followed vaccination. At the end of last week and early this week, THL received a further five reports in which narcolepsy followed vaccination.
The recommendations for seasonal influenza vaccinations will remain unchanged. This year, Finland’s seasonal influenza vaccine will include the vaccine component against the A(H1N1) virus, thus providing cover against swine flu. A seasonal influenza like vaccine incorporating the swine flu vaccine was given to 29 million children in the United States last winter, with no indications of an increased incidence of narcolepsy.
A potential link between the Pandemrix vaccine and narcolepsy will be investigated in Finland by paedriatic neurologists and THL experts working together. It will take several months to get preliminary results. THL is also using its international contacts to gather additional information and to relay its research results abroad for use in the vaccination programmes of other countries.
There have been no further reports of swine flu in Europe since last May. In the southern hemisphere and the tropics, swine flu has been recorded in several countries in recent months, often simultaneously with seasonal influenza viruses. Recently, a wave of swine flu has occurred in New Zealand, particularly in areas where last year’s epidemic was mild. There are also relatively strong swine flu epidemics in some parts of India. The swine flu H1N1 virus appears to have supplanted the subtype of H1N1 virus that previously gave rise to outbreaks of seasonal influenza. During the cycle of seasonal influenza starting this autumn in the northern hemisphere, the viruses involved will probably include both swine flu and the H3N2 subtype.
Preliminary analyses of the impact of the swine flu epidemic in Finland in 2009 indicate that there were far fewer severe cases of influenza among pregnant women, who were among the first to be given the vaccine, than in countries where the first wave of influenza occurred before vaccinations were started. Research is ongoing in several countries to monitor the effect of the vaccine in preventing illness and death.
Enquiries concerning vaccinations
tel. +358 20 610 8787
tel. +358 20 610 8246
Adjunct Professor, Oulu University Hospital
Chair of the Finnish National Advisory Committee on Vaccines
tel. +358 50 387 8887
Enquiries concerning the status of the epidemic
tel. +358 20 610 8670
Short address: http://www.thl.fi/doc/en/22930
Updated 25 Aug 2010