Study flu infection often goes unnoticed

Influenza is without symptoms in three quarters of cases

03/18/2014

The so-called „real“ For most people, flu is characterized by a sudden fever, chills, body aches and pronounced cold symptoms such as cough, cold and sore throat. In fact, influenza in a recent British study, but in only a quarter of patients in this way - in all other cases, however, no disease symptoms develop.

Influenza often comes as a surprise with severe symptoms
People who become infected with influenza viruses often develop symptoms such as fever with simultaneous chills and feel extremely ill and weak. Here then usually strict bed rest and protection is indicated, so that the disease can heal quickly, as further measures come - depending on the existing symptoms - for example painkillers, inhalations or various home remedies for fever into consideration. Fear of true flu is a major concern for many people, but as British researchers have found, only a small proportion of the cases seem to be that bad at all. In 75% of influenza virus-infected patients, however, the disease would be asymptomatic, according to Andrew Hayward and his research team from University College London in the journal „The Lancet Respiratory Medicine“.

Several hundred households in England accompanied by flu season
For their study, the researchers had examined several hundred households in England during the flu season in the period from 2006 to 2011, taking their blood samples in the spring and autumn, and questioning their state of health every week. In addition, in case of symptoms of cold, participants were asked to submit a nasal swab for further study in order to deduce from the sum of the information, who had actually been infected and how the disease had gone on an individual basis. The scientists came to a surprising conclusion: Although an average of 18 percent of non-vaccinated participants had been infected with influenza viruses each winter, only around one-quarter of those affected showed signs of illness at all. The majority of subjects, however, had no complaints and thus did not notice that a contagion had taken place.

Even with the swine flu many cases remain undetected
Also in 2009, when it in England to a rapid spread of H1N1 virus or the so-called „swine flu“ came, the researchers had given an equally high proportion of undiscovered cases: „Seasonal influenza and the 2009 pandemic strain were characterized by a similar high proportion of mainly asymptomatic infections. In the population, the 2009 pandemic strain caused even milder symptoms than the seasonal H3N2 flu“, so the authors in their article. According to the researchers, even a small proportion of those affected had visited a doctor despite infection - which led to the conclusion that previous flu statistics based on family doctor data would greatly underestimate the actual extent of the infections.

Only 16 out of 93 people with confirmed influenza seek out GP
„Most people with a confirmed by the PCR test influenza did not seek medical attention and among those who did, the influenza or flu-like illness has been rarely documented medically. The review of medical records of 93 confirmed by PCR influenza cases in all seasons and of 459 episodes of influenza-like diseases showed that 16 of 93 people with PCR-confirmed influenza (17%) and 96 of 459 people with an influenza-like Disease (21%) had consulted her family doctor“, the researchers continue.

Risk of infection from asymptomatic infections far higher than previously thought
Despite the often mild or missing signs of illness, the flu according to the scientists according to but not downplay. On the contrary, precisely because three quarters of the cases remained undetected, the risk of infection was far higher than previously thought. Accordingly, according to Andrew Hayward, these asymptomatic infections would have to be taken into consideration in the context of prevention in order to prepare better and more effectively for major influenza pandemics. (No)