APH 1997, 55, 299-311:

Influenza: the pandemic risc.

R. Snacken

Keywords: influenza, pandemia, action plan

There are two types of epidemic influenza. On the one hand, there are the almost yearly recurring epidemics whith variable intensity. They are due to circulation of an influenzavirus with minor mutations in capsular proteins. On the other hand, there are the influenza epidemics with a pandemic style of which the onset is unpredictable. They cause a high mortality, such as the Spanish influenza in 1918, which caused 20 million deaths. An influenza pandemia is due to an upcoming influenzavirus A as a result of a genetic transformation or by a reappearing old virus, and its explosive propagation in time and space. This influenzavirus presents new antigenic properties for which the population doesn't possess any immunoprotection.

Within the framework of the Sanitary Plan for Infectious Diseases of the Ministry of Social Affairs, Public Health and Environment, a Belgian action plan has been made in case of influenza pandemia. The major objective of the plan is to reduce as much as possible, the catastrophic impact that could be the result of an influenza pandemia. Respecting strictly the measures in the plan, from the prepandemic period untill eruption of the virus, should make it possible to avoid extreme measures such as the closing of public services. When an enhancing strain emerges without any epidemic propension, epidemiological surveillance can avoid useless measures, like the systematic vaccination of the population with a specific but quickly made vaccine.