Elk jaar een nieuw griepvaccin. Hoe wordt de samenstelling ervan bepaald?

The production process of influenza vaccines for seasonal influenza takes about six months. Twice each year, in February for the northern hemisphere and in September for the southern hemisphere, the World Health Organization provides recommendations for the composition of the influenza vaccine for the coming influenza season. However, due to the continuous evolution of the viruses it is not possible to predict with absolute certainty which influenza viruses with which antigenic properties will cause the next influenza epidemic. Because of this, the antigenic properties of the vaccine strain occasionally may not fully match the epidemic viruses. As a result, the vaccine effectiveness might be reduced. In addition, the seasonal influenza vaccine offers little or no protection against completely new (pandemic) influenza viruses, which often originate in animals. Therefore, continuous comprehensive surveillance of circulating influenza viruses, the epidemiology of influenza, and the vaccine effectiveness, during influenza epidemics is crucial to provide timely information to take counter measures if unexpected patterns are observed. Counter measures include for example increasing capacity in primary health care and intensive care in hospitals, and treatment of severely ill patients with antiviral drugs. In addition, the information is also pivotal for recommending the composition of the vaccine to be used in the next influenza season