Flu (Influenza): Causes, Symptoms, Types and Treatment

What is the flu (influenza)?

The flu, or influenza, is a contagious viral infection that primarily affects the respiratory system. It is caused by influenza viruses and can lead to mild to severe illness, and in some cases, even death. Symptoms often include fever, chills, cough, sore throat, body aches, fatigue, and headaches. The flu is usually seasonal and can spread through respiratory droplets when an infected person coughs, sneezes, or talks. Vaccination is an effective way to prevent the flu.

When is flu season?

Flu season can vary, but it generally occurs during the colder months in the fall and winter. In temperate regions, such as North America and Europe, flu activity usually peaks between December and February. However, it can start as early as October and extend into May. In tropical regions, flu season can occur at any time of the year but may have fluctuations based on local climate patterns. It's essential to stay informed about flu activity in your area and take preventive measures, such as getting vaccinated, to protect yourself and others.

How common is the flu?

The flu is relatively common, and its occurrence can vary from year to year. In the United States alone, it's estimated that millions of people get sick with the flu each year. The severity of flu seasons can also fluctuate, with some years experiencing more widespread outbreaks and higher numbers of cases and others being milder.

The World Health Organization (WHO) estimates that the flu affects 3 to 5 million people globally and causes around 290,000 to 650,000 respiratory-related deaths annually. Keep in mind that these numbers can change based on various factors, including the effectiveness of the flu vaccine and the circulating strains of the virus. Vaccination remains a crucial measure to reduce the impact of the flu and its complications.

What is the difference between the flu and the common cold?

The flu (influenza) and the common cold are both respiratory illnesses caused by different viruses, and they share some similar symptoms. However, there are key differences between the two:

● Causative Viruses:

 The flu is caused by influenza viruses, while the common cold can be caused by various viruses, most commonly rhinoviruses.

● Onset and Severity: 

The flu typically has a sudden and more severe onset of symptoms, including high fever, body aches, and fatigue. On the other hand, the common cold usually starts gradually and presents with milder symptoms, such as a runny or stuffy nose, sneezing, and a mild cough.

● Fever: 

Fever is common with the flu but is less common or rare with the common cold.

● Body Aches: 

Muscle and body aches are more common with the flu and less common with the common cold.

● Complications:

 The flu can lead to more severe complications, especially in vulnerable populations like the elderly, young children, and people with weakened immune systems. Common colds generally do not cause serious complications.

● Seasonality:

 The flu is often seasonal, with peak activity during fall and winter. The common cold can occur at any time of the year.

Both the flu and the common cold are viral infections that can be transmitted through respiratory droplets from an infected person, so practicing good hygiene and taking preventive measures, such as frequent handwashing and avoiding close contact with sick individuals, can help reduce the risk of getting either illness.

How do I know if I have the flu or COVID-19?

Distinguishing between the flu (influenza) and COVID-19 based on symptoms alone can be challenging, as they share many similarities. Both illnesses can cause respiratory symptoms like coughing, fever, fatigue, body aches, sore throat, and difficulty breathing. However, there are some differences that may help you differentiate between the two:

■ Loss of Taste and Smell: 

Anosmia (loss of smell) and ageusia (loss of taste) are more commonly associated with COVID-19 than the flu.

■ Gastrointestinal Symptoms:

 COVID-19 can sometimes cause gastrointestinal symptoms like nausea, vomiting, or diarrhea, which are less common with the flu.

■ Progression and Severity: 

COVID-19 may have a slower onset of symptoms and can cause more severe respiratory issues, especially in some individuals.

■ Seasonality: 

The flu is usually more prevalent during specific seasons (fall and winter), while COVID-19 can occur at any time of the year.

If you suspect you have been exposed to either the flu or COVID-19, it's essential to get tested to determine the specific cause of your symptoms. Additionally, follow public health guidelines, such as wearing masks, practicing good hand hygiene, maintaining physical distance, and seeking medical advice if needed. These precautions can help prevent the spread of both illnesses and protect yourself and others.

Who is at higher risk for complications from the flu?

Certain groups of people are at higher risk of experiencing complications from the flu (influenza).

 These groups include:

● Elderly individuals (aged 65 years and older): 

Older adults are more susceptible to severe flu complications due to age-related changes in their immune system.

● Young children: 

Children, especially those under the age of 5, are at an increased risk of flu-related complications, particularly if they are younger than 2 years old.

● Pregnant women: 

Pregnant women experience changes in their immune system, heart, and lungs, making them more susceptible to severe flu illness.

● Individuals with underlying medical conditions:

 People with chronic health conditions such as asthma, diabetes, heart disease, lung disease, and weakened immune systems have a higher risk of flu-related complications.

● Immunocompromised individuals: 

Those with a weakened immune system due to medical treatments or conditions are at an increased risk of severe flu illness.

● Residents of nursing homes and long-term care facilities: 

Close living quarters in these settings can facilitate the spread of the flu and increase the risk of severe outcomes.

● Indigenous populations: 

Certain indigenous communities may be at higher risk due to limited access to healthcare and other social determinants of health.

It's crucial for individuals in these high-risk groups to take preventive measures, including getting vaccinated annually and seeking medical advice promptly if they develop flu-like symptoms. Vaccination is especially important in providing protection and reducing the severity of the flu for vulnerable populations.

What are the symptoms of the flu?

The symptoms of the flu (influenza) can vary in severity, but common signs and symptoms include:

■ Fever or feeling feverish (not everyone with the flu will have a fever).

■ Cough and/or sore throat.

■ Runny or stuffy nose.

■ Muscle and body aches.

■ Fatigue and weakness.

■ Headache.

■ Chills and/or sweats.

■ Nausea, vomiting, and diarrhea (more common in children).

These symptoms can appear suddenly and may make you feel very unwell. If you experience flu-like symptoms, it's essential to take care of yourself, get plenty of rest, and stay hydrated. Most people recover from the flu within a week or two without any complications. However, if your symptoms are severe or you are in a high-risk group, it's crucial to seek medical attention promptly to prevent potential complications.

What causes the flu?

The flu (influenza) is caused by influenza viruses. There are four main types of influenza viruses: influenza A, influenza B, influenza C, and influenza D. Influenza A and B viruses are the ones that commonly cause seasonal flu outbreaks in humans.

Influenza viruses are highly contagious and primarily spread through respiratory droplets when an infected person coughs, sneezes, or talks. You can also contract the flu by touching surfaces or objects contaminated with the virus and then touching your mouth, nose, or eyes.

The flu viruses undergo frequent changes through a process called antigenic drift and, less commonly, through antigenic shift. These changes are responsible for the flu's ability to cause seasonal outbreaks and can also lead to new strains that may cause pandemics.

To prevent the flu, getting vaccinated is essential. Each year, scientists update the flu vaccine to protect against the most prevalent and potentially dangerous strains of the virus, reducing the risk of infection and severe illness.

Is the flu contagious?

Yes, the flu (influenza) is highly contagious. It spreads from person to person primarily through respiratory droplets produced when an infected person coughs, sneezes, or talks. These droplets can land in the mouths or noses of people nearby or be inhaled into the lungs, leading to infection.

A person with the flu can be contagious even before they show symptoms and for up to seven days after becoming sick. The contagious period can be longer in children and people with weakened immune systems.

Because of its contagious nature, it's important to take preventive measures, such as frequent handwashing, avoiding close contact with sick individuals, covering your mouth and nose when coughing or sneezing, and getting vaccinated. Vaccination is an effective way to reduce the risk of contracting the flu and spreading it to others.

How does the flu spread?

The flu (influenza) spreads primarily through respiratory droplets produced when an infected person talks, coughs, or sneezes. These droplets can travel through the air and can be inhaled by people nearby, leading to infection.

In addition to direct transmission through respiratory droplets, the flu virus can also spread indirectly. For example:

● Touching contaminated surfaces: 

If an infected person touches their nose or mouth and then touches surfaces or objects, such as doorknobs, light switches, or shared items, the virus can survive on these surfaces for a short time. If someone else touches these surfaces and then touches their mouth, nose, or eyes, they may contract the virus.

● Close contact: 

Being in close proximity to an infected person, such as living in the same household or being in crowded settings, can increase the risk of transmission.

● Asymptomatic transmission: 

Some people infected with the flu may not show symptoms but can still spread the virus to others.

Taking preventive measures, such as frequent handwashing, covering your mouth and nose when coughing or sneezing, avoiding close contact with sick individuals, and getting vaccinated, can help reduce the spread of the flu virus.

How long after exposure will I get the flu?

After exposure to the flu virus, the incubation period can vary, but it generally ranges from 1 to 4 days. This means that most people will start experiencing flu symptoms within 1 to 4 days after being exposed to the virus.

However, it's important to note that the incubation period can be longer in some cases, and symptoms may not appear immediately. Some individuals may remain contagious even before showing symptoms, which can contribute to the spread of the virus.

If you suspect you have been exposed to the flu or are experiencing flu-like symptoms, it's essential to take preventive measures, such as staying home to avoid spreading the virus to others and seeking medical advice if needed. Additionally, getting vaccinated annually can help protect you from the flu and reduce the severity of the illness if you do get infected.

How is the flu diagnosed?

The flu (influenza) is typically diagnosed based on your symptoms and a physical examination by a healthcare professional. However, since the flu shares similar symptoms with other respiratory illnesses, it can be challenging to differentiate without further testing.

In some cases, a rapid influenza diagnostic test (RIDT) may be performed. This test involves collecting a swab from your nose or throat, and the results can be available within minutes. It helps detect the presence of influenza viruses and can be particularly useful during flu outbreaks.

In more severe or complicated cases, your healthcare provider may order additional tests, such as a viral culture or a polymerase chain reaction (PCR) test. These tests can confirm the presence of the flu virus and identify the specific type and strain.

If you suspect you have the flu or are experiencing flu-like symptoms, it's essential to seek medical advice promptly. Early diagnosis can help with appropriate management and, if necessary, antiviral treatment, especially for high-risk individuals or severe cases.

How is the flu treated?

The treatment for the flu (influenza) typically involves supportive care to relieve symptoms and help the body fight the infection. In most cases, the flu resolves on its own without specific medical treatment.

 Here are some common approaches for managing the flu:

■ Rest: 

Getting plenty of rest helps your body recover and fight off the virus.

■ Hydration:

 Drink plenty of fluids to prevent dehydration, especially if you have a fever.

■ Over-the-counter medications: 

Over-the-counter pain relievers, such as acetaminophen or ibuprofen, can help reduce fever and alleviate body aches. Be cautious when giving aspirin to children and teenagers, as it has been associated with Reye's syndrome, a rare but serious condition.

■ Antiviral medications:

 In certain cases, especially for people at high risk of complications or those with severe flu symptoms, antiviral medications may be prescribed. These medications can help shorten the duration of the illness and reduce its severity when taken early in the course of the infection.

It's important to seek medical advice if you are in a high-risk group, experiencing severe symptoms, or have underlying health conditions. Your healthcare provider can determine if antiviral medications are appropriate for you.

Prevention is crucial, and the best way to protect yourself from the flu is to get vaccinated annually. The flu vaccine can significantly reduce the risk of infection and its complications. Additionally, practicing good hygiene, such as frequent handwashing and avoiding close contact with sick individuals, can help prevent the spread of the flu virus.

What medications treat the flu?

There are several antiviral medications available that can help treat the flu (influenza). These medications work by inhibiting the replication of the influenza virus and can help shorten the duration of the illness and reduce its severity if taken early in the course of the infection. Some common antiviral medications used to treat the flu include:

● Oseltamivir (Tamiflu): 

Available in oral capsules or liquid form, oseltamivir is approved for use in adults and children over 2 weeks of age.

● Zanamivir (Relenza): 

Administered through an inhaler device, zanamivir is approved for use in adults and children over 7 years of age.

● Peramivir (Rapivab): 

Administered intravenously, peramivir is used in adults and children over 6 months of age.

It's essential to start antiviral treatment as soon as possible after experiencing flu symptoms, ideally within 48 hours, for the medication to be most effective. Antiviral treatment is especially recommended for high-risk individuals and those with severe flu symptoms.

Remember, the flu vaccine remains the best preventive measure against the flu. Antiviral medications are not a substitute for vaccination but can be beneficial in certain cases to reduce the impact of the illness. If you suspect you have the flu or are experiencing flu-like symptoms, consult your healthcare provider for appropriate diagnosis and treatment recommendations.

How do I manage symptoms of the flu?

Managing the symptoms of the flu (influenza) involves supportive care to help relieve discomfort and promote a faster recovery.

 Here are some steps you can take to manage flu symptoms:

■ Rest: 

Get plenty of rest to allow your body to recover and fight the infection.

■ Hydration: 

Drink plenty of fluids, such as water, herbal tea, or clear broths, to prevent dehydration, especially if you have a fever.

■ Over-the-counter medications: 

Over-the-counter pain relievers like acetaminophen or ibuprofen can help reduce fever and alleviate body aches. Follow the recommended dosage and consult your healthcare provider if you have any concerns.

■ Stay warm and comfortable: 

Keep yourself warm and comfortable with blankets and appropriate clothing.

■ Use a humidifier:

 A cool-mist humidifier can help ease respiratory symptoms and soothe a sore throat.

Gargle with warm saltwater: Gargling with warm saltwater can provide temporary relief for a sore throat.

■ Use nasal saline drops or sprays: 

Nasal saline drops or sprays can help relieve nasal congestion and alleviate sinus discomfort.

■ Avoid smoking and secondhand smoke: 

Smoking can irritate your respiratory system and worsen flu symptoms, so it's best to avoid it.

■ Stay isolated: 

To prevent the spread of the flu to others, stay home and avoid close contact with people until you have recovered and are no longer contagious.

■ Seek medical advice: 

If you are in a high-risk group, experience severe symptoms, or have underlying health conditions, consult your healthcare provider for appropriate management and treatment.

Remember, the flu can lead to complications, especially in high-risk individuals, so if you have concerns about your symptoms or overall health, don't hesitate to seek medical advice. Preventive measures like getting vaccinated and practicing good hygiene can also help reduce the risk of contracting the flu.

How can I prevent the flu?

To prevent the flu (influenza), you can take the following preventive measures:

● Get vaccinated: 

The best way to protect yourself from the flu is to get vaccinated annually. The flu vaccine is typically available before the flu season starts and is recommended for everyone over 6 months of age, especially for high-risk individuals.

● Practice good hand hygiene:

 Wash your hands frequently with soap and water for at least 20 seconds, especially after coughing, sneezing, or being in public places. If soap and water are not available, use hand sanitizer with at least 60% alcohol.

● Avoid close contact with sick individuals: 

Try to avoid close contact with people who have flu-like symptoms, and if you are sick, stay home to prevent spreading the virus to others.

● Cover your mouth and nose: 

When coughing or sneezing, use a tissue or the inside of your elbow to cover your mouth and nose, and dispose of used tissues properly.

● Clean and disinfect surfaces: 

Regularly clean and disinfect frequently touched surfaces and objects, such as doorknobs, light switches, electronics, and shared items.

● Practice respiratory etiquette:

 If you are sick, wear a mask to help prevent spreading the virus to others, especially in crowded or public places.

● Boost your immune system:

 Maintain a healthy lifestyle by eating a balanced diet, staying physically active, getting enough sleep, and managing stress.

● Avoid touching your face:

 Avoid touching your eyes, nose, and mouth, as the virus can enter your body through these entry points.

● Follow public health guidelines: 

Stay informed about flu activity in your area and follow any public health recommendations or guidelines to prevent the spread of the flu.

Taking these preventive measures can significantly reduce your risk of contracting the flu and protect you and others from this contagious respiratory illness.

What can I expect if I have the flu?

If you have the flu (influenza), you can expect to experience a range of symptoms that may vary in severity. Common flu symptoms include:

■ Fever or feeling feverish (not everyone with the flu will have a fever).

■ Cough and/or sore throat.

■ Runny or stuffy nose.

■ Muscle and body aches.

■ Fatigue and weakness.

■ Headache.

■ Chills and/or sweats.

■ Nausea, vomiting, and diarrhea (more common in children).

The flu typically has a sudden onset of symptoms, and you may feel very unwell. The severity and duration of the illness can vary from person to person. Most people with the flu start to feel better within a week or two, although fatigue and weakness may persist for a longer time.

For some individuals, especially those in high-risk groups, the flu can lead to more severe complications, such as pneumonia or exacerbation of underlying health conditions.

If you suspect you have the flu, it's essential to manage your symptoms with rest, hydration, and over-the-counter medications for fever and body aches. Stay isolated to prevent spreading the virus to others, and seek medical advice if your symptoms are severe or you have underlying health conditions.

Remember, getting vaccinated annually is the best way to prevent the flu and reduce the risk of severe illness. If you experience flu-like symptoms, it's crucial to confirm the diagnosis with your healthcare provider and follow their recommendations for proper management.

How long does the flu last?

The duration of the flu (influenza) can vary from person to person and depends on several factors, including your overall health, age, and the severity of the infection. In general, flu symptoms typically last for about 1 to 2 weeks.

During the first few days, you may experience the most severe symptoms, such as high fever, body aches, fatigue, and respiratory issues. As the illness progresses, the fever usually subsides, and other symptoms gradually improve.

However, some people may experience lingering fatigue and weakness for a few weeks after the initial symptoms have resolved, especially if the flu was more severe or if they belong to a high-risk group.

If you have underlying health conditions or are in a high-risk group, the flu may take longer to resolve, and complications can occur, so it's essential to monitor your symptoms and seek medical advice if needed.

Remember that getting vaccinated annually can help prevent the flu and its complications, so consider getting the flu vaccine to protect yourself and others from this contagious respiratory illness.

How long is the flu contagious?

The flu (influenza) is contagious from about one day before symptoms appear and up to seven days after the onset of illness. In some cases, especially in children and people with weakened immune systems, the contagious period can be longer and may extend for up to two weeks or more.

During the contagious period, the flu virus can spread through respiratory droplets when an infected person coughs, sneezes, or talks. It can also spread by touching surfaces or objects contaminated with the virus and then touching the mouth, nose, or eyes.

To prevent the spread of the flu to others, it's essential to take preventive measures, such as staying home if you're sick, covering your mouth and nose when coughing or sneezing, practicing good hand hygiene, and avoiding close contact with others, especially those who are more vulnerable to severe flu complications.

Remember that getting vaccinated is the best way to protect yourself from the flu and reduce the risk of spreading the virus to others. If you suspect you have the flu, consider seeking medical advice to confirm the diagnosis and receive appropriate care.

When can I go back to work/school?

If you have the flu (influenza), it's essential to stay home and avoid going to work, school, or public places until you are no longer contagious. The contagious period for the flu can last up to seven days after the onset of symptoms, and in some cases, especially in children and people with weakened immune systems, it can be longer.

As a general guideline, you should consider returning to work or school when you meet the following criteria:

● Fever-free: 

You should be fever-free for at least 24 hours without the use of fever-reducing medications like acetaminophen or ibuprofen.

● Symptoms improved: 

Your symptoms should have improved significantly, and you should have enough energy to resume your regular activities.

● No longer contagious: 

You should no longer be experiencing severe symptoms and should no longer be contagious, as determined by your healthcare provider or based on public health guidelines.

Returning to work or school too early can increase the risk of spreading the virus to others, so it's important to consider the health and well-being of your coworkers, classmates, and the community.

If you have any doubts or concerns about when to go back to work or school, it's best to consult your healthcare provider for guidance based on your individual circumstances and the severity of your illness. Remember that getting vaccinated annually can help prevent the flu and reduce its impact on your health and daily life.

How many people die from the flu each year?

The number of deaths caused by the flu (influenza) each year can vary based on several factors, including the severity of the flu season, the circulating strains of the virus, and the effectiveness of the flu vaccine. The World Health Organization (WHO) estimates that the flu results in 3 to 5 million cases of severe illness globally each year, and the number of flu-related deaths can range from 290,000 to 650,000 annually.

It's important to note that these figures are estimates, and the actual number of flu-related deaths can be challenging to determine precisely due to varying reporting practices and differences in healthcare systems worldwide.

The majority of flu-related deaths occur in vulnerable populations, such as the elderly, young children, and individuals with underlying health conditions. This is why annual flu vaccination is recommended, especially for those at higher risk of severe flu complications, as it can significantly reduce the risk of infection and its impact on public health.

When should I see my healthcare provider?

You should consider seeing your healthcare provider if you experience any of the following concerning symptoms related to the flu (influenza):

■ Difficulty breathing or shortness of breath

■ Chest pain or persistent chest pressure

■ Severe or persistent vomiting

■ Signs of dehydration (e.g., extreme thirst, dark urine, dizziness)

■ High fever that doesn't respond to over-the-counter fever-reducing medications

■ Confusion or altered mental state

■ Seizures

■ Worsening of existing chronic health conditions

Additionally, if you are in a high-risk group for flu-related complications (e.g., elderly, young children, pregnant women, individuals with chronic health conditions), or if you have concerns about the severity of your symptoms, it's best to seek medical advice promptly.

Your healthcare provider can assess your condition, determine if you have the flu or another respiratory illness, and provide appropriate care and guidance. They may recommend antiviral medications if necessary, especially if you are at high risk for complications or have severe symptoms.

Remember, early diagnosis and treatment can be crucial in managing the flu and preventing severe complications. If you are unsure or concerned about your symptoms, don't hesitate to reach out to your healthcare provider for evaluation and support.

When should I go to ER?

You should consider going to the Emergency Room (ER) if you experience any of the following severe or life-threatening symptoms related to the flu (influenza):

● Difficulty breathing or shortness of breath

● Severe chest pain or persistent chest pressure

● Bluish lips or face, indicating a lack of oxygen

● Severe or persistent vomiting

● Signs of dehydration (e.g., extreme thirst, dark urine, dizziness)

● Altered mental state, confusion, or severe lethargy

● Seizures

● Severe weakness or inability to stand or walk

● High fever with severe headache and neck stiffness, which could indicate meningitis

These symptoms may indicate severe flu-related complications or other serious health issues that require immediate medical attention. If you or someone else experiences any of these symptoms, do not delay seeking emergency medical care.

In case of an emergency, call your local emergency number (such as 911 in the United States) or go directly to the nearest Emergency Room. Emergency healthcare professionals are trained to handle critical situations and can provide timely and appropriate care.

What questions should I ask my doctor?

When visiting your doctor regarding the flu or any health concern, it's essential to ask questions to fully understand your condition and the recommended course of action. Here are some questions you may want to consider asking your doctor:

■ What is causing my symptoms, and do I have the flu?

■ What type of flu virus is circulating this season, and am I protected by the current flu vaccine?

■ What can I do at home to manage my symptoms and promote recovery?

■ Are there any specific medications or antiviral treatments that could help me?

■ When should I consider going to the Emergency Room or seeking urgent medical attention?

■ What are the potential complications associated with the flu, and am I at higher risk for severe illness?

■ How long should I stay home from work or school to prevent spreading the virus to others?

■ Are there any specific warning signs or red flags I should watch out for?

■ Should I consider getting the flu vaccine, and when would be the best time to get vaccinated?

■ What preventive measures should I take to protect myself and others from the flu?

Remember to be proactive during your doctor's visit, share any relevant information about your symptoms and medical history, and don't hesitate to ask for clarifications or further explanations if needed. Your doctor is there to help you, and asking questions ensures that you are well-informed and involved in your healthcare decisions.

Is the stomach flu influenza?

No, the stomach flu is not influenza (the flu). While the term "stomach flu" is often used to describe a viral infection that causes gastrointestinal symptoms, it is not related to influenza viruses.

Influenza, or the flu, is primarily a respiratory illness caused by influenza viruses. It usually presents with symptoms such as fever, cough, sore throat, body aches, and fatigue. In some cases, the flu can lead to respiratory complications such as pneumonia.

On the other hand, the "stomach flu" is not caused by influenza viruses but is commonly caused by other viruses, such as norovirus or rotavirus. It is characterized by symptoms like nausea, vomiting, diarrhea, abdominal cramps, and sometimes fever. The stomach flu is primarily a gastrointestinal illness and does not involve the respiratory system like the flu.

Both the flu and the stomach flu are viral infections, but they are caused by different types of viruses and affect different parts of the body. It's essential to differentiate between the two and seek appropriate care if you are experiencing flu-like symptoms or gastrointestinal issues.