Is this year's flu very aggressive or just more contagious?

«We are undergoing the heaviest flu season in 15 years: it is due to various respiratory viruses, the main one being A/H1N1 virus», he declares Fabrizio PregliascoAssociate Professor of Hygiene at the University of Milan and Health Director of Irccs Galeazzi, answering questions.

What are the characteristics of the A/H1N1 virus?
The A/H1N1 pdm09 strain (Pandemic disease Mexico 2009) has been in circulation since 2009. Despite having swine origin, H1N1 immediately became a human influenza virus. In 2009 it caused an epidemicbut less serious than expected because the “grandfather” of H1N1 was the«Spanish» flu with which the older ones, i.e. the category most at risk, had already had contact.

How is it transmitted?
It's a virus air transmission, like other influenza, and spreads mainly in the cold season. Contagion occurs mainly at close range.

Why is the flu so infectious this year?
Low vaccination coverage has nothing to do with it: it has a role in whether emergency rooms are burdened or not because vaccination is used to protect the vulnerable, but if you look at the distribution by age, the cases are mostly children and young people. It's an infectious flu because it is a relatively new virus. It has been with us since 2009 but with different characteristics: this year there is a new variant of A/H1N1. Another element that affects the number of infections is the truly total resumption of normal life and the weather in the first phase of December with very low temperatures for a few days, which triggered the spread of the virus. Finally, this year there is a different, broader reporting modality that includes flu-like syndromes. The system is now called RespiVirNet and before it was called InfluNet, the previous codification was more stringent.

What are the symptoms of this flu?
The typical ones are: fever, cough, muscle pain. Also very common are sore throat, chills, fatigue, headache, loss of appetite. It's just the flu the sudden onset and generally an improvement after the first three days of illness.

How is it treated?
The first rule is to stay at home and rest for 3-4 days. It is important to drink a lot to replenish the liquids and mineral salts lost through sweating and to eat light but nutritious meals, with fruit and vegetables which promote the efficiency of the immune system. Antipyretics are indicated in cases of fever above 38° C. If the fever does not exceed 38°, the most suitable drugs are anti-inflammatorieseffective in reducing symptoms. Fluidifying or mucolytic analgesics against coughs, mouthwashes and lozenges against sore throats can also be useful.

What can be the complications of a bad flu?
Most of the 8-10,000 annual deaths from seasonal flu are deaths “with flu”, people who die of heart and respiratory problems because the flu makes them worse. Then there is a small share of serious cases recorded as “primary viral pneumonia from influenza virus”: in a season of 5-6 million cases there are around 300. The more people get infected, the higher the numbers will rise pneumonia. The flu can also create some QT alterations (the electrical mechanism of the heart) which can be fatal in some people. Another element: the phase following the acute infection creates a window of risk in which they can be introduced bacterial superinfections and this can happen to anyone. In particular, it has been seen that the influenza virus opens the door to pneumococcus, which is why pneumonia is the most widespread complication.

Who is most at risk?
90 percent of deaths occur among those who have over 65 years old, especially with chronic diseases. Even in pregnant women, the evolution of the disease is often more important and creates some difficulties for the unborn child. Dehydration may occur in young children.

What vaccines are available?

The flu vaccine changes formulation every year to be updated: Quadrivalent formulations are currently available that contain two type A viruses (H1N1 and H3N2) and two type B viruses. Flu vaccination is recommended and offered free of charge to people over 60, pregnant and postpartum women, long-term care patients, people with chronic diseases and some categories of workers. It is also recommended for children aged 6 months – 6 years. It takes effect approximately 15 days after inoculation.

* The questions were answered by Fabrizio Pregliasco, Associate Professor of Hygiene at the University of Milan and Health Director of Irccs Galeazzi of Milan.

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