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Flu: Symptoms, Treatment and Prevention – Why the First 48 Hours Matter
KINGRAY ACADEMY · EDUCATIONAL ARTICLE
Flu: Symptoms, Treatment and Prevention – Why the First 48 Hours Matter
You felt well in the evening, but by morning your whole body aches, you are shivering and you barely have the energy to get out of bed. This is how flu often begins.
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Flu can interrupt everyday life within a few hours. Most people recover without complications, but older adults, pregnant women, young children and people with chronic conditions can become more seriously ill.
Flu antivirals work best when started as soon as possible, ideally within the first 48 hours after symptoms begin. Starting them later can still be beneficial, especially for people at high risk of complications or with severe or worsening illness. A clinician decides whether to prescribe them.
Sources for this topic: [3]
Flu is more than a bad cold
Flu is caused by influenza viruses, mainly types A and B. Many other respiratory viruses can cause a common cold.
The difference is often noticeable in how quickly symptoms start and how strongly they affect the whole body.
FLU
Usually starts suddenly
- fever and chills,
- marked muscle and joint aches,
- considerable tiredness and weakness,
- a dry, irritating cough,
- a headache,
- a sore or scratchy throat.
COMMON COLD
Usually starts gradually
- a runny nose and sneezing,
- a blocked nose,
- milder body aches,
- a high fever is less common,
- overall illness is usually milder.
COVID-19 and flu symptoms overlap considerably. Both can cause a cough, fever, fatigue, muscle aches and a sore throat. Symptoms alone cannot always distinguish them reliably. Testing and a medical assessment can help.
How quickly do flu symptoms appear?
The incubation period for flu is usually around 1 to 4 days. However, a person can spread the virus before the first symptoms appear.
typical incubation period
the virus can spread from about a day before illness begins
the virus can continue to spread for several days after symptoms start
Children and people with weakened immune systems may spread the virus for longer. These times are approximate and do not, on their own, determine when returning to a shared setting is safe.
How does flu spread?
- through droplets and aerosols released when coughing, sneezing, talking and breathing,
- through close contact indoors,
- via hands after contact with respiratory secretions.
Typical flu symptoms
Not everyone has every symptom, and flu can occur without a high fever.
Children may more often have nausea, vomiting, diarrhoea, abdominal pain, earache or noticeably reduced energy.
What can you do at home if you have flu?
For uncomplicated illness, the main steps are to rest and monitor your condition.
Stay at home
Avoid work, school, shops and contact with older adults or people with chronic conditions. Your body needs rest, and staying home also protects others.
Drink enough fluids
Fever, faster breathing and sweating increase fluid loss. Water, unsweetened tea or broth are suitable options. Drink regularly, even if you do not feel very thirsty.
Rest and avoid exercise
You do not need to “sweat out” flu through intense exercise. Physical exertion during a fever and an illness affecting the whole body adds unnecessary strain. Return to activity gradually.
Use fever and pain medicines carefully
Paracetamol or ibuprofen may be used for pain and fever if suitable for your health and taken according to the instructions.
Check combination cold and flu remedies: some already contain paracetamol.
Children and teenagers with flu or suspected flu should not be given acetylsalicylic acid because of the risk of serious Reye’s syndrome.
Ventilate rooms
Regular short periods of ventilation help reduce the concentration of respiratory particles indoors. Very dry air can also irritate the nose and throat.
Antibiotics do not treat flu
Flu is caused by a virus. Antibiotics act against bacteria, not the influenza virus.
A clinician may prescribe them if a bacterial complication develops alongside flu.
Antivirals: why are the first two days important?
Prescription medicines used against flu are called antivirals. Oseltamivir is one example.
Antivirals have the greatest effect when started as soon as possible, ideally within 48 hours after symptoms begin.
After 48 hours, it is not automatically too late. Antivirals can still help people at high risk of complications, those admitted to hospital or those with severe or worsening illness. Contact a clinician, who will decide whether the medicine is appropriate.
If you are in a higher-risk group and typical flu symptoms suddenly appear, contact a clinician as soon as possible.
Sources for this topic: [3]
Who is at higher risk of complications?
Examples of groups at higher risk include:
When you improve at first and then get worse
Flu can lead to viral pneumonia or a subsequent bacterial pneumonia. A warning sign is when fever and cough initially improve but then return or become worse.
- a new or returning high fever,
- a worsening cough,
- chest pain,
- shortness of breath,
- coughing up pus-like or bloody mucus,
- a sudden worsening of your general condition.
When should you seek immediate help?
- difficulty breathing or very rapid breathing,
- blue lips or face,
- chest pain or pressure,
- confusion or impaired consciousness,
- marked drowsiness,
- collapse or seizures,
- inability to drink fluids,
- significant dehydration,
- a markedly reduced oxygen saturation,
- a sudden worsening of a chronic condition,
- fever or a cough that returns after an initial improvement.
Warning signs include the spaces between the ribs pulling in with each breath, refusing fluids, not passing urine, unusual sleepiness or not responding as usual.
Any fever in a baby younger than three months needs prompt medical advice.
The main specific preventive measure: annual vaccination
Influenza viruses change, so vaccine composition is reviewed regularly and vaccination is repeated each year.
Vaccination helps reduce the likelihood of illness and, particularly, the risk of severe disease, complications and hospital admission.
A protective immune response develops over about two weeks. It is therefore helpful to be vaccinated before flu becomes widespread.
Vaccination can still be worthwhile later if the flu season is continuing.
A sore arm, a slightly raised temperature or tiredness may occur briefly after vaccination.
How can you reduce the spread of flu?
Dietary supplements, herbs and light devices do not replace vaccination, antivirals or medical treatment for flu.
Correcting a confirmed deficiency of a particular nutrient can be useful, but high doses of vitamins do not destroy the influenza virus.
What should you remember?
Flu usually starts suddenly and can cause considerable fatigue, fever, body aches and a dry cough. It is more than a bad runny nose.
For mild illness, rest, fluids, appropriate fever relief and reduced contact with others can help.
People at higher risk should contact a clinician as soon as possible because antivirals work best when treatment starts early.
Shortness of breath, chest pain, confusion, dehydration or worsening after an initial improvement are reasons for prompt medical assessment.
FAQ – common questions about flu
How does flu usually begin?
Often suddenly, with fever or chills, marked fatigue, body aches, a headache and a dry cough.
Why are the first 48 hours mentioned in flu treatment?
Antivirals have the greatest effect when started as early as possible, ideally within the first 48 hours after symptoms begin. They can still help later in people at high risk of complications or with severe illness. A clinician decides whether to prescribe them.
Do antibiotics help with flu?
Not against the influenza virus itself. A clinician may use antibiotics for a bacterial complication.
Can symptoms always distinguish flu from COVID-19?
No. Symptoms can overlap considerably; testing and a medical assessment can help.
When should you seek immediate help?
Especially for difficulty breathing, chest pain or pressure, impaired consciousness, significant dehydration or a sudden, serious deterioration.
This article is for information and education. It does not replace an individual medical assessment, diagnosis or treatment. A healthcare professional decides whether medicines, antivirals and further steps are suitable for the person’s health.
Sources and further reading
Numbers beside the chapters refer to the supporting sources. All sources are listed openly so you can read the original information.
- WHO: seasonal flu, symptoms and prevention
- CDC: flu symptoms and warning signs
- CDC: flu treatment and the importance of early antivirals
- CDC: seasonal flu vaccination
- CDC: how flu spreads and the infectious period
- CDC: groups at higher risk of complications
- NHS: home care, medicines and when to seek advice
- CDC: what to do when ill and the aspirin warning for children
- European Commission: the 112 emergency number in the EU