Influenza, commonly called the flu, is a contagious viral infection that mainly affects the respiratory system. It can begin suddenly, leaving you with fever, chills, body aches, headache, cough and overwhelming tiredness. For most otherwise healthy people, influenza gets better within about a week, although cough and fatigue can last longer. However, influenza can occasionally cause serious complications, particularly in older adults, young children, pregnant women and people with certain chronic medical conditions.
Influenza is also easy to confuse with COVID-19, a common cold and other respiratory infections. Because the symptoms overlap, testing may sometimes be necessary to determine which virus is responsible.
If you are currently seeing more people around you with flu-like symptoms, you may also be wondering whether influenza A is more dangerous, whether the 2026 flu is unusually severe, how quickly influenza can be treated, and what you should eat or drink while recovering. Here is a practical, evidence-based guide.
What is influenza?
Influenza is an acute respiratory infection caused by influenza viruses. These viruses primarily infect the nose, throat and lungs. Influenza A and influenza B are the main types responsible for seasonal influenza outbreaks in humans.
There are four recognised influenza virus types: A, B, C and D. Influenza A and B are responsible for seasonal flu in people. Influenza C generally causes milder illness, while influenza D mainly affects cattle and is not known to cause human disease.
Influenza spreads mainly through respiratory droplets produced when an infected person coughs, sneezes or talks. You can also become infected after touching a contaminated surface and then touching your mouth, nose or eyes.
Symptoms usually begin around one to four days after infection, with approximately two days being typical. A person can spread influenza before they realise they are sick and is generally most contagious during the first few days of illness.
What is influenza caused by?
Influenza is caused by infection with an influenza virus, not by cold weather, eating particular foods or simply being exposed to rain.
Influenza A and B viruses constantly change. This is one reason people can develop influenza more than once and why flu vaccines are updated periodically. Influenza A is particularly diverse and includes subtypes such as A(H1N1) and A(H3N2).
The virus can spread from one person to another through respiratory droplets and, less commonly, contaminated surfaces. People can be infectious from approximately a day before symptoms appear and for several days afterwards.
What is the first symptom of influenza?
There isn’t one universal first symptom, but influenza often has a sudden onset.
A person may feel perfectly well and then develop fever or chills, headache, body aches, marked tiredness or a cough over a relatively short period. This sudden onset is one feature that can distinguish flu from the common cold, which often develops more gradually.
Not everyone with influenza develops a fever, so the absence of fever does not automatically rule out the flu.
What are 5 symptoms of influenza?
Five of the most common influenza symptoms are:
- Fever or feeling feverish with chills
- Cough
- Muscle or body aches
- Headache
- Fatigue or extreme tiredness
Other symptoms can include sore throat, runny or stuffy nose, sweating, eye irritation and, particularly in children, vomiting or diarrhea.
The flu often feels more intense than an ordinary cold. A person may describe it as being suddenly “hit by a truck” because of the combination of fever, aches and exhaustion.
While most symptoms resolve within 7–14 days, complications may develop in vulnerable individuals.
Is influenza very serious?
Usually, no—but it can be.
Most healthy people recover from influenza without complications. However, influenza can sometimes lead to pneumonia, sinus or ear infections, worsening of asthma or other chronic diseases, and less commonly inflammation involving the heart, brain or muscles.
The risk is higher among:
- Adults aged 65 and above
- Young children, particularly those under 5
- Pregnant women
- People with asthma or chronic lung disease
- People with heart disease or diabetes
- People with weakened immune systems
- People with certain other chronic medical conditions
CDC also notes that serious influenza complications can occur in otherwise healthy people, although the risk is generally higher in recognised high-risk groups.
Is influenza a high risk?
Influenza is not automatically a high-risk illness for every person. For a healthy adult, it will usually be self-limiting.
However, influenza becomes more concerning if you belong to a high-risk group or develop severe symptoms. Pregnancy, very young or advanced age, chronic lung disease, heart disease, diabetes and reduced immunity can increase the risk of complications.
Seek urgent medical attention if influenza is accompanied by difficulty breathing, shortness of breath, chest pain or pressure, confusion, severe weakness, seizures, significant dehydration or worsening of an existing medical condition.
Which organ is affected by influenza?
Influenza primarily affects the respiratory system, particularly the nose, throat and lungs.
However, influenza is not necessarily confined to the respiratory tract. Severe infection or complications can involve other organs and tissues. For example, influenza can contribute to pneumonia and, less commonly, inflammation of the heart, brain or surrounding tissues, as well as muscle inflammation or damage.
This is why severe influenza should not simply be dismissed as “just a fever and cold.”
Is influenza A worse than influenza B?
Influenza A is not automatically worse in every individual case.
Both influenza A and B can cause anything from mild to severe illness. However, influenza A is responsible for most seasonal influenza activity in many settings and is the only influenza type known to have caused influenza pandemics. Influenza A also has subtypes such as H1N1 and H3N2, whereas influenza B is classified into lineages rather than subtypes.
So, if a test says influenza A, it does not necessarily mean that the person will become seriously ill. The individual’s age, health, immunity, viral strain and presence of complications are all important.
What is the deadliest type of influenza?
There is no single influenza type that can accurately be labelled the “deadliest” in every situation.
Historically, influenza A viruses have caused major pandemics, including the 1918 pandemic, because certain new influenza A viruses can acquire the ability to spread efficiently among people with little existing immunity.
Some avian influenza A viruses, such as H5N1, can cause very severe disease in people following certain animal exposures. However, these are different from the seasonal influenza A viruses that commonly circulate in the community.
For everyday seasonal flu, the important point is not to focus on a particular label such as A or B. Severe symptoms and individual risk factors matter more.
Is influenza worse than COVID?
There is no simple answer because the severity of both diseases varies by age, health status, immunity, circulating viruses and other factors.
Influenza and COVID-19 are caused by different viruses. Flu is caused by influenza viruses, while COVID-19 is caused by SARS-CoV-2. Some people can develop severe illness from either infection.
You also cannot reliably determine whether someone has influenza or COVID-19 simply by looking at symptoms. Both can cause fever, cough, fatigue, sore throat, body aches, headache, runny nose, shortness of breath, vomiting and diarrhoea.
Therefore, asking whether flu is “worse” than COVID-19 is less useful than asking which infection you have and whether you have risk factors for complications.
How do I know if I have COVID or influenza?
Symptoms alone cannot reliably distinguish influenza from COVID-19.
A sudden onset of fever, chills, body aches and severe fatigue may suggest influenza, but COVID-19 can produce many of the same symptoms. Loss or change of taste or smell may occur with COVID-19, but it is not sufficient on its own to make a diagnosis.
Testing can help. Depending on what is available, healthcare providers can use influenza tests, COVID-19 tests or multiplex tests capable of detecting more than one respiratory virus.
This distinction matters because treatment options are different.
How to get rid of influenza A fast?
There is no guaranteed way to make influenza A disappear overnight.
The most effective way to shorten illness in appropriate patients is early antiviral treatment. Influenza antivirals work best when started within one to two days of symptoms beginning. They can reduce the duration and severity of illness and may reduce certain complications.
Antiviral medicines are prescription medications, so they should be taken only after appropriate medical advice.
People at higher risk of complications should contact a healthcare professional promptly rather than waiting several days to see whether symptoms improve. Importantly, antibiotics do not treat influenza because influenza is caused by a virus, not bacteria.
For otherwise healthy people with uncomplicated flu, rest, adequate fluids and treatment of symptoms are often sufficient.
What is the treatment for influenza A?
Treatment depends on the severity of illness and the person’s risk factors.
Antiviral medicines
Prescription antiviral medicines can be used for influenza. Options include oseltamivir, zanamivir, peramivir and baloxavir, depending on the patient’s circumstances and current clinical recommendations.
They work best when started early, ideally within the first 48 hours. However, people with severe illness, hospitalisation or a high risk of complications may still benefit from antiviral treatment when treatment begins later.
Symptom relief
For uncomplicated flu, treatment may include:
- Plenty of fluids
- Adequate rest and sleep
- Fever and pain relief when appropriate
- Light, nutritious meals
- Avoiding strenuous activity while unwell
Do not start antibiotics simply because you have influenza. Antibiotics are used for bacterial infections and do not kill influenza viruses.
Is influenza cured?
Influenza usually resolves on its own, but there isn’t a medicine that instantly “cures” the infection.
Most people recover within around a week, although cough and tiredness can continue for longer. Antiviral medicines can shorten illness and reduce the risk of some complications when used appropriately.
If symptoms initially improve but then suddenly become worse, medical assessment is important because this can sometimes indicate a complication or secondary infection.
Will vitamin C help with flu?
Vitamin C is important for normal immune function, but vitamin C is not a proven treatment that cures influenza.
Taking large amounts of vitamin C after you develop flu should not be viewed as a substitute for appropriate medical treatment. A balanced diet that provides adequate vitamin C is sensible, but there is no need to rely on high-dose supplements to “kill” the flu virus.
What to drink to heal flu?
No drink can directly eliminate the influenza virus, but staying hydrated is important while you recover.
Good choices include:
- Plain water
- Warm water
- Clear soups and broths
- Oral rehydration solutions when there is significant fluid loss
- Coconut water
- Herbal or caffeine-free drinks
- Warm lemon water
- Diluted fruit juices
If you have fever, sweating, vomiting or diarrhoea, your fluid requirements may increase.
Warm liquids may also feel soothing when you have a sore throat or congested nose. The goal is hydration and comfort, not a specific “flu-healing” drink.
What are the 7 foods that fight the flu?
No food can directly kill influenza viruses. However, certain foods can provide fluids, calories, protein, vitamins and minerals while your body is recovering.
Seven practical choices are:
- Chicken or vegetable soup – provides fluid, salt and calories and can be easy to tolerate.
- Citrus fruits – oranges, sweet lime and grapefruit provide vitamin C and fluids.
- Bananas – soft, easy to digest and useful when appetite is low.
- Eggs – provide high-quality protein and are usually easy to prepare.
- Yogurt or curd – provides protein and calories and may be easier to eat than a heavy meal.
- Oatmeal or porridge – provides energy and is gentle on the stomach.
- Cooked vegetables and leafy greens – provide vitamins, minerals and fibre without requiring a heavy meal.
The most important principle is to eat what you can tolerate. You do not need an elaborate “flu diet.”
What are the best foods to eat when you have the flu?
The best foods are generally light, nutritious and easy to digest.
If you have little appetite, smaller meals throughout the day may be easier than trying to eat a large plate of food.
Soups, dal, khichdi, rice, porridge, bananas, toast, eggs, yoghurt, cooked vegetables and fruits can all be reasonable options depending on your tolerance.
If nausea or diarrhoea is present, temporarily choosing simpler foods and focusing on fluids may be more comfortable.
Avoid relying heavily on alcohol or very sugary drinks during recovery, as they are not substitutes for proper hydration and nutrition.
Why is the 2026 flu so bad?
If you are asking this because of the current influenza activity being reported in India in 2026, it is important to put the situation into perspective.
Indian health authorities reported in August 2026 that seasonal influenza activity is being closely monitored, but no new or unusual influenza strain or unusual genetic shift has been detected. The Indian Council of Medical Research has described the current situation as consistent with seasonal influenza patterns and said there is no cause for panic.
At the same time, some parts of India have reported noticeable increases in influenza cases. That can make the flu feel unusually widespread at a local level.
Influenza activity also varies considerably by region and season. Recent WHO surveillance has shown increased influenza activity in parts of the South-East Asia region, with influenza A(H3) among the predominant detected viruses in the Western Pacific surveillance zone.
Therefore, it would be misleading to say that there is a single “2026 flu virus” that is universally more dangerous. Increased transmission, seasonal conditions, the circulating strains and differences in population immunity can all influence how noticeable a particular flu season becomes.
When should you get tested for influenza?
Testing is particularly useful when the result could change treatment or medical decisions.
Consider speaking to a healthcare professional about testing if you have significant flu-like symptoms, especially if you are in a high-risk group, have severe symptoms or need to distinguish influenza from COVID-19.
Rapid influenza tests are available, although some rapid antigen tests can miss infections. Molecular tests are generally more sensitive. Some tests can simultaneously detect influenza A, influenza B and SARS-CoV-2.
How can you prevent influenza?
The best protection against seasonal influenza is vaccination.
WHO and CDC recommend annual influenza vaccination because influenza viruses continually evolve and immunity can decline over time. Vaccination reduces the risk of influenza and, importantly, can reduce the risk of serious complications.
WHO’s recommendations for the 2026–2027 Northern Hemisphere influenza vaccine include components targeting influenza A(H1N1)pdm09, influenza A(H3N2) and influenza B/Victoria.
Other useful precautions include:
- Wash your hands regularly.
- Cover coughs and sneezes.
- Improve ventilation and indoor air quality.
- Avoid close contact with people who are sick.
- Stay home when you are unwell where possible.
- Avoid sharing personal items such as drinking glasses.
- Follow medical advice regarding vaccination.
When should you see a doctor for influenza?
Most uncomplicated influenza can be managed at home, but don’t ignore warning signs.
Seek prompt medical attention if you develop:
- Difficulty breathing or shortness of breath
- Chest pain or pressure
- Severe or persistent dizziness
- Confusion or difficulty staying awake
- Severe dehydration
- Seizures
- Severe weakness
- Severe muscle pain
- A worsening of an existing chronic illness
- Symptoms that improve and then return or become significantly worse
Children can also develop rapid breathing, blue or grey lips, dehydration or other concerning symptoms that require urgent assessment.
People at increased risk of complications should contact a healthcare professional early, particularly because antiviral treatment is most useful when started promptly.
Frequently asked questions about influenza
Is influenza very serious?
Usually, influenza is self-limiting and most healthy people recover within about a week. However, it can cause serious complications such as pneumonia and can be dangerous for high-risk individuals.
What is influenza caused by?
Influenza is caused by influenza viruses, primarily influenza A and B viruses in seasonal human infections. It spreads mainly through respiratory droplets.
What are 5 symptoms of influenza?
The five classic symptoms are fever or chills, cough, body aches, headache and fatigue. Sore throat and a runny or stuffy nose are also common.
Is influenza curable?
Most cases resolve naturally. Antiviral medicines can shorten illness and reduce complications when prescribed appropriately, especially when started early.
Is influenza worse than COVID?
Neither is universally worse. Both can cause mild to severe disease, and symptoms overlap considerably. Testing is needed to reliably distinguish them.
Is COVID caused by influenza?
No. COVID-19 is caused by SARS-CoV-2, a coronavirus. Influenza is caused by influenza viruses.
How do I get rid of influenza A fast?
There is no instant cure. If appropriate, prescription antiviral treatment started within the first one to two days can shorten illness and reduce the risk of complications.
What is the first symptom of influenza?
Influenza often begins suddenly with fever or chills, headache, body aches, fatigue or cough. There is no single symptom that occurs first in everyone.
Will vitamin C help with flu?
Vitamin C supports normal immune function but is not a cure for influenza. A balanced diet is preferable to relying on high-dose supplements.
What should I drink when I have flu?
Water, clear soups, broths, oral rehydration solutions when needed, coconut water and other non-alcoholic fluids can help maintain hydration.
What are the best foods to eat during flu?
Light, nutritious foods such as soup, dal, khichdi, porridge, bananas, eggs, yoghurt, fruits and cooked vegetables are practical choices.
What is the deadliest type of influenza?
Influenza A viruses have caused major pandemics and some zoonotic influenza A viruses can cause severe disease. However, there is no single seasonal influenza type that is automatically the “deadliest.”
Which organ is affected by influenza?
Influenza primarily affects the respiratory system, including the nose, throat and lungs. Severe complications can affect other organs and tissues.
Which is more harmful, influenza A or B?
Influenza A is associated with more viral diversity and is the only type known to cause pandemics, but both A and B can cause serious illness. Individual risk factors and complications are more important than the letter A or B alone.
The bottom line
Influenza can leave you feeling considerably worse than an ordinary cold, but most healthy people recover without serious complications. The key is recognising the symptoms early, staying hydrated, getting adequate rest and seeking medical advice promptly if you are at higher risk or develop warning signs.
If influenza is suspected, remember that influenza A, influenza B and COVID-19 can look remarkably similar. A laboratory test can help identify the infection when knowing the specific virus will affect treatment or precautions.
And while foods, fluids and vitamin-rich meals can support recovery, they should complement—not replace—appropriate medical care. For people at higher risk, early antiviral treatment can be particularly important because it works best when started as soon as possible after symptoms begin.
Medical disclaimer: This article is intended for general health information and does not replace a consultation with a qualified healthcare professional. If you have severe symptoms, belong to a high-risk group or are unsure whether you have influenza or COVID-19, seek appropriate medical advice.
To consult a Pulmonologist/Chest Specialist at Sparsh Diagnostic Centre, call our helpline number 9830117733.
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Disclaimer:
No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.
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