Effectiveness of Influenza Vaccination (Alfarix)in Preventing Clinical Influenza Cases Among General Practitioners: Non-Randomized Clinical Trial.

Two important aspects emerge when considering influenza vaccination of general practitioners as advocated by many guidelines. Besides the personal protection the vaccine especially needs to prevent transmission of influenza between GPs and their patients. In long-term elderly hospitals a possible benefit of influenza vaccination of the healthcare workers was noticed in reducing mortality among the elderly. But this specific situation is not fully transmissible to the general practice.

GPs, having yearly close contact with several influenza cases, built up a high basic immunity and probably only suffer from minor symptoms. The question remains if the vaccine is adding substantial benefit to this natural acquired immunity. In addition doubts are raised in the literature if an inactivated vaccine, which elicit especially humoral immune response, can give enough protection against virus replication and subclinical influenza infections. Until now no effectiveness studies of influenza vaccination were performed among GPs. High time to look more closer to these issues.

Comparisons: the effectiveness of an inactivated influenza vaccine compared with no vaccine in GPs against clinical respiratory tract infections and more particular against influenza cases with influenza positive nose and throat swabs (diagnosed by RT-PCR), besides serological defined influenza cases and taking important independent variables into account