Immunization safety is pivotal in determining the success or failure of national vaccine-based disease control programs. Safety issues have derailed vaccine programmes in the developing and in the developed world. This is critical as vaccine safety concerns can be real and may require prompt interventions to minimize the impact. Active monitoring of vaccine safety is important to build up trust and to be able to respond quickly to safety signals, which are likely to arise. The ability to respond quickly and to provide high quality information on the level of risk may avoid rapid deterioration of trust in the vaccine and therefore potentially save more lives.

 

Currently, most European Member States are preparing to monitor the safety of pandemic influenza vaccines (PIV). However, national and regional capacity and expertise, as well as the sensitivity and timeliness of vaccine safety monitoring and response systems vary considerably
The VAESCO consortium is a growing network of investigators from European member states exploring the feasibility and demonstrating the benefits of collaborative post-licensure epidemiological studies investigating the safety of human vaccines. The VAESCO consortium recognizes the need for concerted international action to enhance the capacity of national immunization programs to independently, consistently, and credibly gather and assess safety data of pandemic influenza vaccines. It also recognizes that a common strategy of European members states based on generally accepted standards would significantly improve data comparability across European Member States and thus enhance the value of national safety data.

A shared methodology will help national decision-making by facilitating the interpretation of local data in the European context through scientific validation processes and potentially provide more statistical power by meta-analyzing results across countries. It will give credibility to high quality local data and thus strengthen the communication needs of national authorities. A common European approach will help mobilizing local resources and directing them towards a common aim. Concerted action among European member states will shore up local capacity through the support of internationally recognized experts in the field. It may also compensate for the lack of national capacity through the added benefit of international collaborative engagement.

AEFI surveillance in Europe is primarily the responsibility of European Medicines Agency (EMA). In the draft CHMP recommendations for pharmacovigilance of PIV EMA highlights the need for active collaboration between public health organizations, regulatory authorities and marketing authorization holders with regard to the pandemic. It strongly encourages a common approach with shared methodologies and resources beyond evaluation of periodic safety update reports (PSUR) and prospective cohorts with a limited number of immunized subjects.

The VAESCO network is in a unique position to contribute to a European approach to investigating PIV safety. This is due to the established and flexible infrastructure of the Network and the outstanding accrual of expertise in the field of vaccine safety assessment among the participants, contributing the different necessary professional backgrounds including academia, patient care, and public health, in addition to regulatory organizations.

The European Center for Disease Control (ECDC) has requested VAESCO for the set up of a European Vaccine Safety Datalink (EVSD) to monitor the safety of vaccines in Europe. Partners from a third of all European member states have consented to participate already.
The emerging H1N1 pandemic for which governments prepare for potential mass vaccination programs demands for accelerated action of the VAESCO consortium. The ECDC has allocated additional funding for this joined effort of partners involved in the program for setting up a VSD in Europe.

The main concern with the envisioned H1N1 vaccination is the occurrence of neuro-immunologic events such as Guillain Barré syndrome (GBS). On the one hand, GBS is associated with preceding influenza like illness. Thus, immunization should primarily protect from GBS and reduce the annual incidence rate. On the other hand H1N1 vaccines may induce cross-reactive anti-ganglioside antibodies 1, which is associated with the development of GBS. Several studies have shown an increased risk after influenza vaccination ranging from relative risks of more than 7 in 1957 to around 1.5 in 1976 and 1992-1994 2-4. Other neuro-immunolgic diseases such as neuritis (Multiple Sclerosis) and a selection of specific adverse reactions also have the attention of the ECDC and EMA. The safety monitoring of H1N1 will have to focus on these diseases.

In order to put safety alerts in perspective through analyses of observed and expected number of cases, background rates of the pre-specified events will be needed. The present study was set up to provide these rates in each country and across Europe. The obtained background rates will serve as an objective country-specific reference. The integrated data serve to provide a measure of the heterogeneity.
In the present report we provide background rates of ESI to allow for timely estimations on the observed/expected number of cases, that will be necessary to counter the initial safety concerns on PIV.