Effectiveness of Influenza Vaccination Among General Practitioners

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

Status

Completed

Phases

Phase 4

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT00221676

Enrollment

300

Registered

2005-09-22

Start date

2002-07-31

Completion date

2004-06-30

Last updated

2006-11-28

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Influenza

Keywords

influenza vaccine, general practitioner

Brief summary

Besides the personal protection, influenza vaccination especially needs to prevent transmission of influenza between GPs and their patients. The question remains if the vaccine is adding substantial benefit to the natural acquired immunity of GPs. Doubts are raised 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. This study will assess the effectiveness of an inactivated influenza 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).

Detailed description

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

Interventions

BIOLOGICALAlfarix

Study design

Allocation

NON_RANDOMIZED

Intervention model

PARALLEL

Primary purpose

PREVENTION

Masking

NONE

Eligibility

Sex/Gender

ALL

Age

25 Years to 76 Years

Healthy volunteers

Yes

Inclusion criteria

general practitioner with an active practice in Flanders, Belgium -

Exclusion criteria

other specialists in medicine \-

Design outcomes

Primary

Measure	Time frame
number of respiratory tract infections	—
number of influenza cases defined as a RTI with positive nose and throat swabs	—
number of influenza cases defined as a RTI with 4-fold IgG titre rise	—

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026