Influenza, commonly known as the flu, is an acute respiratory infection caused by influenza viruses (Types A, B, and C) that suddenly develops, causes fever, and typically affects the nose, throat, and later the lungs.
The flu spreads through droplets containing the infectious viruses that are expelled into the environment when a person coughs or sneezes. Influenza outbreaks are most commonly seen during the onset of winter (October – November) and spring (March – April). Influenza virus infections, which hold a special place among contagious diseases, are known to cause widespread epidemics every 1-3 years, have been observed for 400 years, and affect approximately 350 million people worldwide each year.
Symptoms of the flu appear suddenly within a day or two after infection. Common symptoms include fever (38 – 41°C), headache, fatigue, dry cough, sore throat, runny nose, and muscle aches.
The severity of the flu lies in its potential to cause serious complications in individuals who are at high risk, have weakened immune systems, are elderly, or have significant health problems. While most infected individuals recover within one to two weeks, 5-20% of the patient group may develop secondary illnesses such as pneumonia, bronchitis, sinusitis, and middle ear infections. In developed societies with an increasing elderly population, flu-related mortality rates are also rising. Therefore, early diagnosis and monitoring and treating high-risk and elderly patients who are likely to develop complications from influenza are of great importance.
Influenza and the common cold are different illnesses with distinct causative agents, although their symptoms are often confused. Since the clinical signs mentioned above can also be seen in upper respiratory tract infections, the common cold, and bronchitis, it is important to differentiate between “Influenza” and “Influenza-like upper respiratory tract infections.” An influenza diagnosis can be definitively made by isolating the virus. However, because virus cultures require special systems and take a long time, they may not be effective for patient treatment. Virus types identified in cultures are used to monitor outbreaks and assist in preparing vaccines. Influenza Type A is more frequently observed and has a greater impact compared to Influenza Type B.
Today, rapid ELISA kits are widely used for influenza diagnosis, providing quick results. These rapid diagnostic kits can detect the presence of Influenza A and B viruses in throat secretions, nasal discharge, and sputum within one to two hours. However, I believe that routine ELISA testing for influenza infections is not practical.
In the treatment of influenza, antibiotics are ineffective and are often unnecessarily used. Unnecessary antibiotic use can lead to antibiotic resistance in bacteria, delaying the treatment of some infections and increasing treatment costs. Antibiotics should only be used when secondary bacterial infections (such as sinusitis, pneumonia, and middle ear inflammation) develop during the illness.
There are four different antiviral medications for the treatment of influenza (Amantadine, Rimantadine, Zanamivir, and Oseltamivir). In our country, only Zanamivir and Oseltamivir are available as commercial preparations. When antiviral medications are started within the first two days of infection, the symptoms of the illness are milder. These medications must be used strictly under the advice and supervision of a doctor. Aspirin is not recommended for children and young people with influenza, as it can rarely but dangerously cause “Reye’s Syndrome.” Instead of Aspirin, rest, plenty of fluids, and medications that alleviate symptoms should be preferred.
Vaccination before the flu season is important for preventing the disease. However, due to the increasing frequency of influenza infections with different strains, getting vaccinated does not always provide protection during the winter. Considering the complications and side effects of vaccines, I do not routinely recommend the flu vaccine to my patients except for those in high-risk groups.
Vaccination is particularly beneficial for children, those over 65 years old, and individuals with chronic illnesses (such as asthma, heart failure, diabetes, and cancer). It is also important for hospital workers to get vaccinated to prevent hospital-acquired infections. Droplets containing the influenza virus, which are spread around the mouth and hands during coughing and sneezing, play a significant role in the transmission of the infection. Therefore, it is crucial to keep hands clean by washing them regularly.