Adults get the real flu once every 5 years.

Adults get the real flu about once every five years, scientists estimate, based on research in China.

Although many of you will feel sick more often, other flu-like infections will be to blame, the international team says.

Scientists examined blood samples from 151 volunteers between the ages of seven and eighty-one to assess how often they fell victim to flu infections. A similar study in the UK will test whether the findings apply to them.

The collection of this kind of data has not been done before in this region. Experts will be able to better understand who is at risk of such an infection, how often, and to what extent the disease spreads among people.

The study, published in the biological journal PloS, looked at nine major factors in flu infections that circulated around the world between 1968 and 2009.

Flu

These are all types of influenza A (H3N2) viruses. The flu or influenza (known in the past as the Spanish flu) is an acute infectious disease, representing one of the most contagious infections. It is caused by Influenza virus type A and Influenza virus type B.

It is characterized by acute intoxication – high fever, headache, strong muscle pains and catarrhal inflammation of the upper respiratory tract.

Blood Clues

Scientists from Imperial College London and institutes in the US and China tested volunteers’ blood for antibodies to reveal whether they had ever been infected with the viruses, and how often.

They found that children get the flu on average every two years, and the frequency of flu infections decreases with age.

From age 30 onward, flu infections tended to occur twice a decade in the people studied. The researchers point out that their findings do not apply to other populations, but they possibly could.

Dr. Stephen Riley of the Central Medical Research Council, senior author of the study, said: “The exact infection rate varies with background levels of influenza and vaccination.”

“We found that flu infection is less common in adults than some people think,” he continued.

“During childhood and adolescence, it is more common, perhaps because children have contact with other people more often,” added the researcher.

Professor Ron Eccles, from Cardiff University, said: “This is an interesting study. Many people confuse the common cold with the flu infection. But some infections can only be detected if a blood test is done.”

Cold or flu?

Cold and flu viruses are spread by infected droplets. They are caused by viruses but you can hardly tell they are the same except based on the subjective symptoms.

Both can cause fever and sore throat, coughing and sneezing. They are also spread from person to person.

What one person considers the flu, another may consider a bad cold. With the common cold, symptoms tend to work their way up the head and affect mostly the nose and throat.

Flu is a more serious illness, which in order to pass, you have to stay in bed for several days, well wrapped and drinking a lot of tea. Symptoms include muscle and eye, bone, throat pain, sneezing and coughing, as well as ailments such as stuffy nose and runny nose.