As temperatures grow colder, the risk of catching the flu virus rises as well. This year, Australia is experiencing the worst flu epidemic in 15 years. Are Europe and North America also facing the same threat? For National Influenza Vaccination Week, we answer the most important questions about the current flu season.
Influenza, also called the flu, is one of the most significant infectious respiratory diseases. It is caused by the subtype A or B influenza virus. Worldwide 3–5 million people contract influenza every year and approximately 250,000–500,000 die from the illness. The flu has hit Australia especially hard this year, with more than 200,000 cases – twice as many as last year. Now the flu season has begun in the northern hemisphere. The number of cases is growing but is still in the normal range; no one knows what the rest of the season will bring.
How effective is the flu vaccine?
Risk groups are urgently advised to get a flu vaccination. Yet even then there is no 100% guarantee because of the extreme variability of flu viruses. They mutate and are always developing new subtypes. Every year, the composition of the vaccines is adapted as necessary and according to WHO recommendations (also see information from the Robert Koch Institute), but not all variants can be covered. This year the effectiveness of the vaccine in Australia was a meager 17 percent, as reported by the Ärztezeitung.
What strains of influenza are currently prevalent?
The composition of the current flu vaccine is the same as last season’s (also see the latest Influenza Update of the WHO). This year, most of the cases are influenza A (H3N2) and B viruses. The WHO recommends the following vaccine composition for the northern hemisphere:
- an A/Michigan/45/2015 (H1N1)pdm09-like virus
- an A/Hong Kong/4801/2014 (H3N2)-like virus
- a B/Brisbane/60/2008-like virus
Tetravalent vaccines should also contain a B/Phuket/3073/2013-like virus.
What diagnostic tests confirm influenza?
Because influenza viruses are so variable, the diagnostic tests that confirm the flu are reviewed regularly. The real-time PCR tests RIDA®GENE Flu (Art. No. PG0505), RIDA®GENE Flu LC2.0 (Art. No. PG0525) and RIDA®GENE Flu & RSV (Art. No. PG0545) have been confirmed as effective in detecting the influenza A and B strains cited by the WHO and many other strains.