THE DISEASE - INFLUENZA FACTS
What is the clinical case definition of influenza?
The clinical case definition of Influenza includes the following criteria:
- Fever greater or equal to 38°C
- At least one respiratory symptom – cough, sore throat, nasal symptoms
- At least one systemic symptom – headache, myalgia (aches/pains), sweats/chills (feeling feverish), lethargy (fatigue)
During an influenza outbreak, approximately 60% of cases can be diagnosed on symptomatology. The definitive diagnosis of influenza is made in the laboratory by virus isolation, by the demonstration of viral antigen in the epithelial cells in respiratory secretions, by nucleic acid detection or by demonstration of an increase in a specific antibody in the blood.
Influenza virus can be found in respiratory secretions during the first 3 to 5 days of infection. The quantity of virus shed subsequently diminishes rapidly in adults, however, shedding may occur in children for 2 weeks or longer.
Why is influenza immunisation needed every year?
Annual immunisation is required for two key reasons: first, because protection wanes over time; second, because each year influenza can be caused by different influenza viruses that are not represented in the previous year’s vaccine. The vaccine is reformulated annually to contain the most up to date composition of viral antigens, to ensure your patient gets the best vaccine match against likely circulating strains.
Influenza vaccine strains for 2010
- A/ California/7/2009 (H1N1)-like strain
- A/Perth/16/2009 (H3N2)-like strain
- B/Brisbane/60/2008-like strain
Annual influenza immunisation is strongly reccomended for all healthcare workers
Annual influenza immunisation is strongly recommended for all healthcare workers to protect those patients at greater risk of developing complications following Influenza illness.
Studies demonstrate that annual influenza vaccine for healthcare workers significantly reduces illness and death among the patients they care for.
Only 20-40% of healthcare workers in NZ received an influenza vaccination each year and many staff continue to work when sick, thereby exposing influenza illness to patients and co-workers.
Healthcare workers have a responsibility to protect vulnerable patients from the serious health threat of influenza illness. Annual influenza immunisations results in improved patient safety, improved employee safety and decreased healthcare expenditure.
At present some organisations offer subsidised vaccine for staff. Please check with your organisation to see if the vaccine is subsidised for you.
