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Influenza

Influenza is a viral infection in your respiratory system including nose, throat, and lungs. Influenza is commonly known as the flu, but it is different from stomach flu virus or gastroenteritis virus which is the cause of diarrhea and vomiting.

Usually, However, in some cases, it can cause complications, leading to death.

Symptoms of influenza

The symptoms of influenza such as sneezing, runny nose, and sore throat may seem like a common cold. However, influenza is more likely to suddenly appear and make you feel much worse than a common cold which develops gradually.

Here are signs and symptoms of influenza.

• Fever, chills, and sweating
• Headache and muscle ache
• Sore throat and dry cough
• Eye pain
• Runny nose
• Shortness of breath
• Diarrhea and vomiting which are more common in children

When to see a doctor

In most cases, patients with influenza can rest at home. However, it is recommended to seek immediate medical care if you have higher risks of developing complications. Antiviral medications can shorten the illness period and prevent other serious problems which may occur.

If you have the following emergency signs and symptoms, please see your doctor right away.

Emergency signs and symptoms in adults:

• Chest pain, shortness of breath
• Persistent dizziness
• Seizures
• Severe weakness or muscle pain
• Aggravation of preexisting medical conditions

Emergency signs and symptoms in children:

• Chest pain, difficulty breathing
• Dehydration
• Blue lips
• Seizures
• Severe muscle pain
• Aggravation of preexisting medical conditions

Causes of Influenza

The influenza viruses can be transmitted through inhalation of airborne droplets. When people with influenza cough, sneeze, or talk, you may inhale the droplets in the air or pick up germs on the surface of an object such as a mobile phone or computer keyboard.

People with influenza are contagious one day before their symptom onset and the transmission continues for another 5 days after the symptoms appear. Immunocompromised people can spread germs longer than others.

New strains of influenza viruses constantly emerge. Normally you are immune to the influenza if you have the disease in the past – either by getting sick or vaccinated. If a new influenza virus is like the one you had before, your existing antibodies can prevent infection or decrease its severity. However, the drop in antibody levels over time is typical.

If you are exposed to a new emerging influenza virus which is different from what you have had before, your antibodies cannot flight and protect you from the new strain.

Risk factors

• Children aged 6 months to 5 years old and adults aged 65 years or older.
• Crowded workplace or living condition.
• Weakened immune system due to ongoing cancer treatment, blood cancer, HIV/AIDS, organ transplant, long-term use of steroids or anti-rejection medications.
• Chronic illnesses such as diabetes, asthma, heart disease, liver disease, blood disease, nervous system diseases, metabolic disorders, respiratory problems.
• Long-term use of aspirin in people under 19 years old which can lead to the development of Reye’s syndrome stimulated by influenza.
• Pregnant women especially in their second or third trimesters.

Complications

In young and healthy people, influenza can resolve within one or two weeks without any lasting effects. However, in children and adults with higher risks, they may develop complications such as:

• Acute respiratory distress syndrome.
• Asthma flare-ups.
• Ear infections.
• Heart problems.
• Pneumonia which can be very serious particular in the elderly or people with a chronic disease.

Preventions

The influenza vaccination can decrease the severity of symptoms and hospitalization. Symptoms of influenza and COVID-19 are similar. The flu vaccination can reduce and prevent the confusion between these two diseases. Getting both COVID-19 and influenza vaccines at the same time is possible. A flu vaccine is safe for people who have an egg allergy.

Influenza transmission control

Because the flu vaccine cannot provide 100 % protection. A good hygiene practice can significantly help prevent the transmission.

• Wash your hands regularly with soap and water or alcohol-based hand sanitizers.
• Refrain from touching your eyes, nose, and mouth.
• Sneeze or cough into your elbow or a tissue paper and wash your hands.
• Clean surfaces of your phones or other things that are often touched.
• Avoid crowded areas especially during flu season.
• Try to avoid sick people.

Diagnosis

A physical exam will be performed to look for signs and symptoms of influenza. Influenza diagnostic tests will be prescribed especially when it is the flu season. You can simultaneously be infected with both influenza and COVID-19 and tests for both diseases may be given.

Treatment

Rest and drink plenty of liquids to help fight the flu. An antiviral medication will be prescribed if you have risk of complications or serious infection.

Taking antiviral drug can make you feel nauseous and would like to vomit. Taking them with food can decrease the side effects.

Home care

• Drink plenty of fluids such as juice, water, or warm soups to stay hydrated.
• Rest and sleep to let your immune system combat the viral infection.
• Take pain relievers to reduce influenza symptoms such as headache and muscle ache. Due to the risk of developing Reye’s syndrome, aspirin should not be used in children and teenagers recovering from influenza.

To prevent airborne transmission in your family and community, stay at home until the flu resolves. Avoid meeting other people when you are sick. Wash your hands frequently. If you need to leave your home or go to a hospital, always wear a face mask.