What are the symptoms and duration of the flu?

 Each year, the flu epidemic causes bothersome symptoms in millions of people in France, but also major complications in several thousand of them. Doctissimo presents the signs of this viral disease, as well as its average duration.

Summary

Flu state or real flu? Length of incubation, contagion and recovery from influenza

Flu vaccination

Influenza treatment

Symptoms and duration of influenza

The flu is widely described in the oldest medical books. It is therefore one of the oldest viral diseases . However, we sometimes tend to use the term influenza for a set of diseases that do not fall under the influenza virus , but a simple flu state.

Flu state or real flu? 

Several characteristics distinguish the flu syndrome from the real flu. 

SYMPTOMS OF THE FLU-LIKE CONDITION (OR FLU-LIKE ILLNESS)

Symptoms of ILI are often transient and moderate in intensity . Those responsible for these "false flu" are respiratory syncytial viruses (RSV), para-influenza viruses , adenoviruses , rhinoviruses , enteroviruses , coronaviruses, etc.

SYMPTOMS OF THE REAL FLU, VIRAL AND SEASONAL IN ORIGIN

Conversely, the real flu, seasonal and viral , is characterized by symptoms of a strong intensity occurring suddenly  :

. A fever intense (around 39 ° C);

. Severe fatigue (asthenia);

. Of headaches (headaches);

. Body aches (diffuse muscle and joint pain);  

. The chills ;

. Sometimes a cough and nasal congestion ...  

Far from being as harmless as its counterparts, the influenza virus remains in France one of the leading causes of infectious death . He is responsible for several thousand deaths each year (on average, 1,500 to 2,000 deaths per year in France).

FLU VIRUSES (INFLUENZA)

The influenza virus belongs to the family Orthomyxoviridae and genus Influenzavirus , of which there are three types A, B and C . Type A and B viruses are responsible for annual influenza epidemics, but only type A viruses are responsible for influenza pandemics . The type C virus appears to be linked to sporadic cases.

Type A viruses are the most common and the most virulent  ; several subtypes can be distinguished on the basis of their surface antigens, hemagglutinin (H1 to H16) and neuraminidase (N1 to N9). So that gives 144 possible combinations , but for seasonal flu , the viruses involved boil down to  H1, H2, H3 and N1 or N2 responsible for the annual flu.

Length of incubation, contagion and recovery from influenza

The incubation period of influenza (between contamination by the virus and the first symptoms) varies between 24 and 48 hours . The patient is contagious for an average of six days , including before symptoms appear. The flu  is transmitted by secretions : coughs, postilions, sneezes but also by contact with an infected person or touched and contaminated objects (door handle ...). In non-compromised subjects, recovery is complete after one to two weeks .

VIRUS LIFESPAN 

The influenza virus has a variable lifespan, it of:

. 5 minutes on the skin;

. a few hours in the dried secretions;

. 8 to 12 hours on handkerchiefs , clothes, papers etc;

. several days on inert surfaces (buttons, door handle, etc.).

Flu vaccination

The vaccination against influenza is recommended for:

. The pregnant women , regardless of trimester;

People, including children from the age of 6 months, with the following conditions:

. Chronic bronchopulmonary disorders meeting the criteria for ALD 14 ( asthma  and COPD );

. Chronic obstructive or restrictive respiratory insufficiency whatever the cause, including neuromuscular diseases at risk of respiratory decompensation, upper or lower airway malformations, pulmonary malformations or malformations of the thoracic cage;

. Chronic respiratory diseases which do not meet the criteria for ALD but which may be aggravated or decompensated by an influenza illness, including asthma , chronic bronchitis, bronchiectasis, bronchial hyper-reactivity;

. Broncho-pulmonary dysplasias;

. Cystic fibrosis ;

. Cyanogenic congenital heart disease or with PAH and / or heart failure,

. Severe heart failure ;

. Serious valve disease;

. Serious cardiac arrhythmias justifying long-term treatment;

. Coronary diseases;

. history of stroke ;

. Serious forms of neurological and muscular disorders (including myopathy , poliomyelitis , myasthenia gravis , Charcot's disease ),

. Paraplegia and quadriplegia with diaphragmatic involvement,

. Severe chronic nephropathies ,

. Nephrotic syndromes,

. Sickle cell anemia , homozygous and heterozygous double S / C, spa-SCD

. Diabetes type 1 and type 2,

. Primary or acquired immune deficiencies (oncological and haematological pathologies, organ and hematopoietic stem cell transplants, hereditary immune deficiencies, inflammatory and / or autoimmune diseases receiving immunosuppressive treatment), except people who receive regular treatment with immunoglobulins; people infected with HIV regardless of their age and immunovirological status,

. Chronic liver disease with or without cirrhosis ;

. The obese individuals with a body mass index (BMI) greater than or equal to 40 kg / m2, without associated pathology or suffering from other pathologies than those mentioned above;

. The people staying in a care facility immediately and in a medico accommodation establishment whatever their age;

. The family circle of infants under 6 months of age with serious influenza risk factors defined as follows: premature babies , in particular those carrying sequelae such as broncho-dysplasia, and children with congenital heart disease, congenital immune deficiency, pathology pulmonary, neurological or neuromuscular or a long-lasting condition.

Vaccination should be repeated every year , as new strains of influenza virus appear and are constantly changing. Influenza epidemics can occur from October to March . The best period to be vaccinated is from October to mid-December, a period of 15 days is necessary for your body for the production of antibodies responsible for your protection.

Influenza treatment

In people who are not particularly fragile , the body is able to effectively fight the infection provided a little rest , good rehydration and  antipyretic drugs (fever reducer). The advice is therefore simple:

. Stay in bed  ;

. Drink a lot  ;

. Clear the nose  ;

. Treat fever .

For children , a few particularities are in order. The choice of the antipyretic depends on its age , your doctor will judge the usefulness of using this or that drug. To find out more, find out in our article " Flu, how to lower children's fever? ".

It is also possible to resort to antivirals , able to reduce the duration and intensity of symptoms. Today there are two classes:

. Inhibitors of the viral protein M2  ( amantadine  and rimantadine) are active against influenza A viruses, but have some drawbacks: they have poor renal , hepatic and neurological tolerance . In addition, resistance appears quickly;

. Neuraminidase inhibitors  (zanamivir -  Relenza  ® - and oseltamivir -  Tamiflu  ®) are believed to be effective in reducing the intensity and duration of symptoms if administered within 48 hours of the onset of symptoms. These drugs would also have a preventive action vis-à-vis influenza infection. But a study * published in 2012 summarizing all the work on oseltamivir ( Tamiflu  ®) arrives at more disappointing conclusions regarding its effects. Including published and unpublished double-blind studies comparing this drug to placebo, the benefits would be limited to a reduction in symptom duration of 20 hoursif the medicine is taken within 24 hours of the first symptoms. No statistically significant reduction in serious complications (pneumonia or hospitalization) was noted by the authors. What to review its usefulness in the event of an influenza pandemic?

Remember that the usefulness of antibiotics is limited to the prevention of complications of influenza (bacterial infections). They are totally helpless in the face of the virus 

FLU PREVENTION 

Simple actions can limit contamination: 

. Wash your hands regularly with soap and water or, failing that, with a hydrolalcoholic solution;

. Cover your mouth as soon as you cough or sneeze, and teach children to do the same;

. Wear a mask  ; 

. Limit contact and avoid crowded places when you are contaminated;

. Air out your home every day.