Flu ≠ Cold! Here’s how you should deal with the often-ignored flu →

Recently, the topic of influenza has been trending on the Internet. Some people think that influenza is just a large common cold, which will be gone after a few days of discomfort.

However, getting the flu can cause serious consequences, even life-threatening. The World Health Organization estimates that flu can cause 3 million to 5 million severe illnesses and 290,000 to 650,000 deaths worldwide each year. Currently, Beijing is still at a high risk of respiratory infectious diseases such as flu. How to distinguish between flu and the common cold? How to choose antiviral drugs? How to determine whether medical treatment is needed?

What is influenza? Influenza (flu for short) is an acute respiratory infectious disease caused by influenza viruses. Influenza viruses are divided into four types: A, B, C, and D. Currently, the main influenza A virus subtypes H1N1 and H3N2 and influenza B virus Victoria strain are prevalent in the human population .

How do influenza and the common cold differ?

The common cold is mostly characterized by upper respiratory tract symptoms (nasal congestion, runny nose, sore throat), while systemic symptoms such as fatigue and loss of appetite are mild.

Influenza is highly contagious and the general population is susceptible. During the peak influenza season, a clear history of contact with influenza patients and typical influenza symptoms are highly suggestive of influenza. It is often difficult to distinguish mild influenza from the common cold. For people at high risk of influenza, it is recommended to go to a hospital for specialist diagnosis and treatment in a timely manner.

Why does influenza also cause death?

Influenza has an acute onset and changes rapidly. For those without complications, the fever gradually subsides and systemic symptoms improve 3 to 5 days after onset, but it takes a long time for the cough and physical strength to recover.

If you experience persistent high fever, severe cough, difficulty breathing, or complications, you must go to the hospital for professional diagnosis and treatment in time to avoid delaying the condition.

Among them, pneumonia is the most common complication. Some influenza patients may also have infections such as bacteria, other viruses, atypical pathogens, and fungi on the basis of viral pneumonia. If not treated in time, chest images may quickly develop into "white lungs", leading to respiratory failure, septic shock and other life-threatening conditions.

Other complications include nervous system damage such as encephalitis, myelitis, and encephalopathy; cardiac damage mainly includes myocarditis and pericarditis; myositis and rhabdomyolysis, which are mainly manifested as myalgia and muscle weakness, and in severe cases can cause acute kidney injury.

Influenza viruses can also cause microthrombi in the body, leading to secondary embolic diseases such as pulmonary embolism, myocardial infarction, etc., which are life-threatening and even lead to death.

Which groups of people are likely to develop severe influenza symptoms?

Children under 5 years old (children under 2 years old are more likely to develop serious complications);

Elderly people aged ≥65 years;

People with chronic underlying diseases and immunosuppression: chronic respiratory diseases (chronic obstructive pulmonary disease, bronchial asthma), cardiovascular diseases (coronary heart disease, chronic heart failure, etc., excluding hypertension), kidney disease, liver disease, blood system diseases, nervous system and neuromuscular diseases, metabolic and endocrine system diseases, malignant tumors, immunosuppression (organ transplant recipients);

Obese people;

Pregnant women and women within 4 weeks after giving birth.

What are the commonly used antiviral drugs for influenza? How to choose?

At present, there are three main types of anti-influenza virus drugs in my country:

Neuraminidase inhibitors (oseltamivir, peramivir, zanamivir)

RNA polymerase inhibitors (mabaloxavir, favipiravir)

Hemagglutinin inhibitors (Abidol)

There are two most commonly used oral antiviral drugs, oseltamivir and mabaloxavir. Different dosage forms of the drug are suitable for different groups of people:

Oseltamivir capsules/granules are suitable for children aged ≥ 1 year and adults. Oseltamivir dry suspension is suitable for children aged 2 weeks and above and adults.

The oral dose for adults is 75 mg twice a day for 5 days.

Children need to calculate the oral dose according to their weight, as follows:

Oral dosage for children under 1 year old: 3 mg/kg each time for 2 weeks to 8 months; 3.5 mg/kg each time for 9 to 11 months. Oral dosage for children 1 year old and above: 30 mg each time for those weighing ≤15 kg; 45 mg each time for those weighing 15 kg < ≤23 kg; 60 mg each time for those weighing 23 kg < ≤40 kg; 75 mg each time for those weighing >40 kg. The above oral dosages are taken twice a day, and the course of treatment is 5 days.

Mabaloxavir: Mabaloxavir tablets are suitable for children aged ≥5 years and adults, and dry suspension is suitable for children aged 5 to 12 years, both of which are taken orally once. The oral dose is: 80 mg for those weighing ≥80 kg; 40 mg for those weighing 20 kg or less and less than 80 kg, and 2 mg/kg for those weighing less than 20 kg.

For influenza patients with impaired liver and kidney function, or during pregnancy or breastfeeding, it is necessary to consult a specialist to select antiviral drugs and determine the oral dosage.

When should antiviral drugs be taken orally? How long is the course of treatment?

During the peak influenza season, for people who test positive for influenza virus antigen/nucleic acid and have high-risk factors for severe influenza, it is recommended to receive antiviral treatment as soon as possible within 48 hours of onset to achieve the greatest benefit.

For people at high risk of severe influenza and patients with severe influenza, if the onset time exceeds 48 hours but the influenza virus test is still positive, antiviral treatment should still be carried out. For patients with severe influenza, the antiviral treatment course can be appropriately extended based on the results of influenza virus antigen/nucleic acid test. It is not recommended to use antiviral drugs with the same mechanism of action in combination or increase the drug dose.

In addition to antiviral drugs, how can influenza be treated symptomatically?

For those with fever, if the body temperature is less than 38.5℃, warm water bath and ice pack can be given for physical cooling. For those with body temperature ≥38.5℃, antipyretic drugs such as ibuprofen and acetaminophen can be given. Children should avoid using aspirin or aspirin-containing and other salicylic acid preparations.

For patients with obvious dry cough, antitussive drugs such as dextromethorphan hydrobromide can be given, and for patients with obvious sputum, expectorants such as carbocysteine ​​and acetylcysteine ​​can be taken. When there is no evidence of bacterial infection, avoid blind or inappropriate use of antibiotics.

Symptoms do not improve after taking oral medication

Can I increase the dosage of the drug or take multiple drugs at the same time?

It takes time to recover from any disease. After getting the flu, fever, cough, loss of appetite, and physical strength also take time to recover. You must strictly follow the doctor's instructions when taking medication. Do not increase the dosage of the drug or take several similar drugs at the same time. This often does not work and may cause other adverse reactions.

If the symptoms persist or worsen, it is recommended to go to a hospital for specialist treatment immediately to avoid delaying the condition.

QHow to prevent influenza?

Before the flu season arrives, getting a flu vaccine is the most effective way to prevent the flu, which can significantly reduce the incidence of flu and the risk of serious complications. WHO recommends that high-risk groups for flu, such as the elderly, children, pregnant women, patients with chronic diseases and medical staff, should get a flu vaccine every year.

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Author: Chen Ying

Doctor of Traditional Chinese Medicine Respiratory Medicine, Beijing Hepingli Hospital, attending physician

Editor: Dong Xiaoxian

Reviewer: Zhang Chao, Li Peiyuan