Flu(Influenza) in Adults

Flu (Influenza)

Aches, chills, coughs —the flu is a disturbing respiratory condition. By detecting and treating symptoms early, you can help prevent the spread of the flu. But what are the symptoms? How does a flu differ from the common cold? And is Crocin (Paracetamol) good for treating symptoms of flu?

Flu – What are the signs, causes, and treatment options for influenza?

The flu is a common seasonal viral infection of the respiratory tract.
The flu is caused by influenza viruses that can spread quickly from one person to another. It is incredibly common, and most people will get the flu at some point in their lives. It can cause serious illness and, in some cases, even death.

The World Health Organization estimates that around three to five million people suffer severe cases of influenza each year. An average 290,000 to 650,000 people die from respiratory issues caused by flu viruses annually1. However, most cases of flu can be treated at home with flu medicine and bed rest.


What are the most common flu symptoms?

It can be difficult to distinguish influenza from the common cold. A fever is often the first sign of the illness.

Influenza usually begins abruptly. The exact symptoms will differ from person to person, but some of the first signs include fever, muscle pain, and a general feeling of discomfort and tiredness@.

1. Fever: A fever happens when your body is trying to fight an infection. If your body temperature rises above 38 °C or >100°F, you have a fever.

2. Myalgia: Muscle pain (or myalgia) is a common complaint of the flu. Your muscles might ache only in some places or it can feel like your entire body is hurting. There are many other reasons for myalgia, so if this is your only sign, it may not be influenza.

3. Discomfort: Malaise describes a sensation of general weakness and discomfort. You will notice that something is not right and start to feel unwell. It’s often accompanied by fatigue when you have the flu.

Flu symptoms – What to look out for?

Signs and symptoms of seasonal influenza include a fever, cough, body aches and muscle pain, chills, fatigue and a general feeling of discomfort.
Because the flu spreads quickly, detecting symptoms early can encourage people to isolate and prevent further spreading of the virus x. You’ll also be able to treat yourself quickly and avoid the illness getting worse.
Common signsxi of the flu are:

  • Fever: A high temperature is a sign that your body is trying to fight a viral infection. For a reliable result, you should use a thermometer and measure your temperature (read the instruction on the label of the thermometer you are using)xii. But not everyone with the flu gets a fever. According to estimates, around 70% of people get a flu without fever2.
  • Body aches: When you’re coming down with a flu or cold, body and muscle aches are incredibly common. You may feel achy in the back, legs, and head more than in other areas of the body.
  • Chills: Shivers are a common reaction to your body preparing for a fever and often come on just before you notice a raised temperature.
  • Fatigue: Feeling weaker and more tired than normal is one of the earliest symptoms of the flu. But be aware that fatigue alone is not always an indication of influenza. Exhaustion is a common sign of many other illnesses.
  • Cough: A dry cough, a tight chest, or wheezing may be indicators that you’re coming down with a flu. More often though, respiratory tract ailments come after the body aches and chills. Coughing can be very uncomfortable. It’s normal to cough up phlegm or mucus, but a persistent or lingering cough should be looked at by a doctor.
  • Sore throat: The itchy or sore throat you’re feeling is a common sign of influenza. It may also be painful to swallow food or even drinks.
  • Vomiting or diarrhoea: Not everyone who has the flu will suffer from gastrointestinal upset. But some people (and more commonly childrenxiii) can feel nauseous and get diarrhoea.

What’s the difference between a cold and the flu?xiv


Common cold






Not common in adults or mild; more common in children

Very common




Body aches





Very common

Stuffy and runny nose

Very common


Sore throat

Very common





Flu medicine – How to treat influenza?

Treatment of seasonal influenza usually includes bed rest, staying warm, and pain medication like Crocin (Paracetamol). If your symptoms persist or get worse, you should see a doctor.
The flu can leave you feeling weak, tired, and unable to focus on your daily tasks. One of the most important things to do when you’re sick is to rest to help your body heal more quickly. From flu tablets to home remedies, which influenza treatmentxv you choose will often depend on the severity of your symptoms.

1. Rest and stay warm: If you notice flu symptoms, you should stay in bed. Sleep has been shown to be restorative and helps the body recover more quickly when you have the flu.vi It’s important that you stay at home to avoid spreading the virus to other people. Also wash your hands more often and use a tissue when sneezingxvi.

2. Rehydrate: Drink plenty of fluids—water, electrolyte-enhanced drinks or decaf tea/coffee—to replenish lost fluids from diarrhea or vomiting. When your body sweats because of fever, you need to replace the lost water. Avoid caffeinated drinks as these can dehydrate you further.

3. Medicine: Paracetamol (the ingredient in Crocin) or ibuprofen can help to relieve pain. It can take around half an hour for acetaminophen like Crocin to work.

4. Antiviral drugs: Antiviral tablets are prescription medicines that help reduce the duration of the flu. They’re given to people who are at higher risk of developing complications from influenza to avoid severe health consequences.vii

What are the complications associated with the flu?

With proper care and treatment, the flu isn’t serious in most cases and should go away within seven days. Symptoms such as a cough can linger longer.xvii

Some people may also develop more severe symptoms and complications after they get the flu. These can be life-threatening so it’s important you recognize them early on.

  1. Pneumonia: Pneumonia is a lung infection that can occur after a flu. It affects children under the age of five and the elderly or immunocompromised individuals more often. More than two million people worldwide die each year from pneumonia3. Symptomsxviii usually develop quickly and include a severe cough. You may also notice blood in your mucus. Pneumonia could make it difficult to breath and you may have severe chest pain. Elevated heartbeat, a high temperature, sweats, and shivers are common.
  2. Bronchitis: A viral infection can cause your airways to become irritated and inflamed. Signs of bronchitisxix include a cough with mucus, a tight chest, fever, and shivers. Bronchitis often precedes pneumonia. If your symptoms last for more than three weeks, make sure you see a doctor.
  3. Sinusitis: Symptoms of a sinus infection include pain and tenderness around the cheeks, forehead, nose, and eyes. Your nose will usually feel stuffy and blocked. There may also be a postnasal drip. Difficulty breathing should be treated by a doctor right away.
  4. Ear infection: If you notice a loss of hearing or discharge coming from one or both of your ears, it’s likely otitis media (more commonly known as a middle ear infection). The viruses that cause influenza can also infect the ear. This should be looked at by a healthcare provider.

Encephalitis: Encephalitis is a very rare complication of the flu. It occurs when the flu virus enters the brain and causes inflammation of the nerve tissue. Signsxx of this infection include a severe headache, very high fever, nausea and vomiting, and mental confusion. You should call for emergency help if you have hallucinations, double vision, seizures or have difficulty speaking or hearing. Encephalitis is a medical emergency.

What is flu? The causes explained

The viruses that cause the flu are known as influenza type A, influenza type B, and influenza type C.xxii Influenza type A is found in many species including humans, pigs, and birds; while types B and C mostly occur in humansxxiii ( Although dogs and pigs5 have been known to be infected with type C). The illness passes from person to person through droplets in the air when people sneeze or cough.

Worldwide, annual flu epidemics are estimated to result in about 3 to 5 million cases of severe illness1. Children are more likely to get the flu than adults under the age of 65.4

Although anyone can get the flu, some people are at a higher riskxxiv of developing complications. They include:

  • Adults over the age of 65
  • People with chronic health conditions like asthma, heart disease, diabetes, and kidney disease
  • People with blood disorders or chronic lung disease
  • People who are obese
  • Children
  • Adults who are immunocompromised
  • Pregnant women

A Flu Shot for Prevention

While influenza is treatable and, in most people, does not cause severe complications, the best action is prevention. Anyone older than six months and without any life-threatening allergies should get vaccinatedviii, according to the US Centers for Disease Control and Prevention.5
Washing your hands regularly,xxi avoiding touching your nose and mouth, and staying home if you’re not feeling well are other ways you can stop the spread of the flu.


1. World. Influenza (Seasonal). Who.int. Published November 6, 2018. https://www.who.int/news-room/fact-sheets/detail/influenza-(seasonal) [Aaccessed 9 November 2020]
2. CHUGHTAI AA, WANG Q, DUNG TC, MACINTYRE CR. The presence of fever in adults with influenza and other viral respiratory infections. Epidemiology and Infection. 2016;145(1):148–155. doi:10.1017/S0950268816002181 [Aaccessed 9 November 2020]
3. S. Bernadeta Dadonaite and Max Roser. Pneumonia. Our World in Data. Global Change Data Lab. https://ourworldindata.org/pneumonia. [Accessed 31 Mar 21]
4. Tokars JI, Olsen SJ, Reed C. Seasonal Incidence of Symptomatic Influenza in the United States. Clinical Infectious Diseases. 2018;66(10):1511–1518. doi:10.1093/cid/cix1060 [Accessed 9 November 2020]
5. Who Should and Who Should not get a Flu Vaccine. Centers for Disease Control and Prevention. Published 2019. https://www.cdc.gov/flu/prevent/whoshouldvax.htm [Accessed 9 November 2020]


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