Introduction

Flu isn’t just a respiratory problem or a high fever. It’s a contagious illness caused by a group of viruses affecting the health of a healthy person and those with weakened immune systems. Currently, there’s a continuous rise in flu cases, despite the DOH’s report of no influenza outbreak of super flu in the Philippines. Whether you are one of those who are experiencing symptoms of the flu, it’s best to be knowledgeable of what causes flu and how it spreads. In this guide, we’ll cover everything from the types of flu, and how the flu virus affects the health of people. Let’s begin! 

What Causes Flu: Understanding Influenza Viruses

The culprit behind influenza is the influenza virus. Flu occurs due to a group of constantly evolving viruses that infect your respiratory system. According to the World Health Organization (WHO) these viruses can cause seasonal epidemics.

Here are the types of influenza viruses:

Influenza A Virus

Influenza A is the most common and typically the most severe type of flu virus affecting humans. What makes influenza type A particularly challenging is its ability to mutate quickly, creating new strains that your immune system hasn’t encountered before. This type causes most seasonal flu outbreaks and has been responsible for major flu pandemics throughout history. 

It can be classified by two proteins on their surface: hemagglutinin (H) and neuraminidase (N). You might have heard of H1N1 or H3N2—these are different subtypes of influenza A virus.

Influenza B Virus

Another type of flu are the Influenza B viruses. It is known to only infect humans and tend to be less severe than influenza A. Although, influenza B can still cause significant illness. 

Furthermore, this type of virus can mutate slower than influenza A and doesn’t cause pandemics. However, they’re still a major contributor to seasonal flu, especially among young children and can circulate alongside influenza A during flu season.

Influenza C Virus

Meanwhile, influenza c viruses isn’t a contagious virus that can trigger an epidemic. Commonly, patients affected by this condition can experience mild respiratory illness that doesn’t lead to severe flu. In short, it can affect humans, but doesn’t pose a significant threat to public health.

Influenza D Virus

The last type of flu is the influenza D virus, which is the only type that doesn’t infect humans. This type of flu is one of the main concerns of livestock owners, specifically cattle owners. However, it is important to understand that animals can’t transmit the influenza d virus to humans.

While influenza d virus isn’t transmissible to humans, drinking unpasteurized milk from an infected cattle can pose a high risk. At the same time, consuming beef from an infected cattle can also be dangerous.

How Does the Flu Spread: What Causes Flu?

Understanding how the flu spreads is crucial for prevention. The influenza virus is incredibly efficient at jumping from person to person, which is why during the flu season, several cases of flu are confirmed. 

Learn how flu spreads through the following transmission methods:

Respiratory Droplets

The most common way flu spreads is through respiratory droplets. When an infected person coughs, sneezes, or even talks, they release tiny droplets containing the flu virus into the air. These droplets can travel up to six feet and land in the mouths or noses of people nearby. 

It is mostly a concern, especially in places with little to no ventilation. People gathering in such a place can easily inhale these respiratory droplets and get infected. 

Indirect Contact or Surface Contact

Another form of transmission is indirect touching of items that may have been harboring the flu virus. Flu viruses can survive on surfaces for up to 48 hours. This means that touching contaminated items like doorknobs, smartphones, shared utensils, and even money can possibly lead to getting the flu.

However, take note that just touching contaminated materials doesn’t automatically get you sick. What causes flu in this form of transmission is when you touch your eyes, nose, or mouth, allowing the virus to enter your respiratory tract. Thus, showing why hand hygiene is so crucial during flu season.

Close Contact Situations

When it comes to transmission of the flu virus, another possible method involves being in close contact with infected people. Take note that people can spread the flu even before they have their symptoms. So, being in close proximity with a person exposed to the virus raises the possibility of you getting infected.

Filipino families often live in multi-generational households, which means when one person gets sick, the virus can quickly spread to young children, parents, and elderly relatives. Schools, offices, markets, and public transportation also create perfect conditions for viral infections to spread.

How Flu Viruses Work in Your Body?

After it enters the body, the virus acts fast and attaches itself to cells in your respiratory tract, specifically in your nose, throat, and lungs. Once it attaches, it hijacks the cells to create new virus particles. Afterward, your immune system fights back against the invasion, which manifests as your flu symptoms.

The fever, body aches, and fatigue you experience aren’t directly caused by the virus destroying your cells. Instead, they’re the result of your immune system releasing chemicals to fight the infection. It’s like your body declaring war on the invader, and unfortunately, you feel caught in the crossfire.

Influenza Virus: Contagious Period

As mentioned, people can be contagious and a carrier of the virus without them knowing. Infected individuals become contagious before they even have their flu symptoms. Incubation period is within 1 to 4 days, this includes the day of exposure until before the symptoms appear. 

Contagious period:

• You are most contagious around 3 to 4 days of being sick (with symptoms showing)
• You are still contagious after 10 days of onset symptoms

Take note that there are cases where an infected person can be asymptomatic. However, they can still spread the virus to other people.

Who’s at a Higher Risk of Getting Infected?

Anyone can develop symptoms of flu, but there are groups of people who are at a higher risk of getting infected. The most vulnerable individuals are those with a weak immune system.

Here are the vulnerable age groups that can face complications and other severe illnesses due to flu.

• Young children: Children under five years old, particularly those younger than two, are at significantly higher risk for serious flu complications. Their immune systems are still developing, making them more susceptible to severe illness.
• Older adults: Adults aged 65 and older face increased vulnerability due to age-related changes in their immune systems. Even healthy adults should take extra precautions during seasonal flu outbreaks. Many Filipino seniors also have underlying health conditions that compound their risk.
• People with weakened immune systems: Individuals with compromised immune systems have a much harder time fighting off influenza infection. (e.g., pregnant women, individuals with chronic conditions, etc.).

Why Immediate Flu Treatment Matters?

Many Filipinos tend to “tough it out” when they get sick, hoping their sore throat, runny nose, muscle aches, and other similar symptoms will pass on their own. However, symptoms of influenza can prolong without proper management.

Here’s why prompt treatment and management are crucial.

1. It Can Prevent Complications

In severe cases, flu causes respiratory failure or worsen chronic medical conditions. At the same time, it can lead to serious complications including pneumonia, bronchitis, sinus infections, and ear infections. It’s best to receive early treatment with antiviral medications to reduce the severity and duration of illness.

2. It Can Stop the Spread of Virus in Filipino Communities

Getting immediate treatment is an advantage not only for yourself, but also for those people around you. When you take proper precautions as you manage your symptoms, you’re preventing the further spread of the virus in your community. 

Practical Prevention Strategies for Filipino Families

Personal Hygiene Practices

One of the most effective ways to prevent getting infected is by practicing proper hygiene. This includes washing your hands with soap for at least 20 seconds as well as using alcohol for further sanitation. It’s best to apply these precautions after coughing, sneezing, or being in public spaces.

Environmental Measures

Another preventive strategy involves the disinfection of your environment. Sanitizing every corner of your home helps to protect you and your family from being exposed to the virus. Practice regular cleaning of your area, and try to improve ventilation in your home to not harbor the virus that can trigger developing an infectious disease.

Social Practices During Flu Season

Furthermore, isolating at home is another effective way to avoid spreading respiratory illness to others. If you’re suffering from flu symptoms, this social practice can help keep your loved ones safe from the virus.

Boosting Your Immune System with Influenza Vaccines

Aside from the natural way of boosting your immune system, you can also benefit more by getting a flu shot. Influenza vaccines, commonly known as flu shots, remain our best defense against seasonal flu. While flu vaccines don’t guarantee you won’t get sick, they significantly reduce your risk of infection and, if you do get sick, typically result in milder illness.

Read this related article to discover more about the natural home remedies for flu.

Super Flu in 2026: Should You Be Alarmed?

According to the Department of Health, there’s no imminent threat yet in the Philippines despite the super flu cases occurred last year. There has been 17 recorded cases of the flu in July 2025, which was caused by the new flu variant H3N2 virus. This strain of influenza is a subtype of influenza A that commonly causes seasonal flu.

Now at the beginning of 2026, Herbosa, DOH secretary claimed that there are number of flu cases, but doesn’t pose any threat yet in the Philippines. Furthermore, there’s no lockdown announcement yet, but Herbosa warns people about the possible health risks for those traveling to places where there are more cases of the new flu strain. Receiving vaccinations for influenza is crucial to ensure immunity.

When to Seek Doctor Consultation

Knowing when to move from home care to professional medical attention is crucial. While many cases of seasonal influenza can be managed at home, certain situations require a doctor’s expertise.

You should consult a doctor if you experience the following:

• difficulty breathing
• persistent chest pain
• sudden dizziness
• confusion
• severe vomiting

Also, you must seek medical care if flu symptoms improve but then return with fever and worse cough. 

Note: For young children, additional warning signs include fast breathing, bluish skin color, not drinking enough fluids, or extreme irritability.

Booking Immediate Doctor Consultation for Flu

If you think you have the flu or just a common cold, consulting a doctor is the ideal choice to determine your current condition. Today, you have telemedicine or online consultation options for easy and instant access to medical care. 

Here are different options to use the online consultation option of NowServing, one of the leading telemedicine platforms in the Philippines.

• Download the NowServing app to your device for seamless communication with a licensed doctor in the Philippines.
• You can also use their online consultation page via the NowServing website.
• For a more specific option, you can try to look for the “Cold & Flu” page to book a doctor that manages this health condition. When booking your doctor, simply choose the online consultation option.

Discover when to only use online consultation for flu with this guide.

Frequently Asked Questions (FAQs) About What Causes Flu

How long does the flu virus survive outside the body?

The flu virus can survive on hard surfaces for up to 48 hours, on soft surfaces like fabric for about 12 hours, and in the air for several hours in the form of respiratory droplets. Furthermore, this survival time varies based on temperature and humidity. Influenza virus tends to survive longer in cold, dry conditions, which is partly why flu season coincides with cooler months.

Does the flu virus thrive in cold, increasing the spread of flu?

As mentioned, the flu virus can survive more in cold, dry conditions. That’s why you can notice more cases of flu in the Philippines during the rainy season. There are reports of an increase in flu cases in different cities, especially in Manila. So, practicing precautions are encouraged.

Can you get the flu from going out with wet hair or being in air-conditioned rooms?

No, there’s no correlation to getting flu and the 2 mentioned conditions. You should remember that influenza is solely caused by influenza viruses. Also, influenza A, B, and C are the only types of flu virus that can affect humans.

Can I get flu from animals?

Animals cannot directly transmit the fly virus to humans. Influenza D virus is a type of flu virus that only affects livestock animals like cattle. Still, you can’t get infected by the influenza D virus, unless you drink unpasteurized milk from an infected animal. Take note that this case of possible transmission is very rare.

How soon after exposure does influenza symptoms appear?

The incubation period for flu is typically one to four days, with an average of two days. This means you can be infected today and not show symptoms until a couple days later. Remember, you can be contagious during this pre-symptomatic period, which is why flu spreads so efficiently through communities.

How long does it take to recover from the flu virus?

In most cases, you can recover from a flu within 7 days. However, you can still be contagious around the 10th day of being sick from flu. So, it’s best to rest a few more days to avoid spreading the virus. At the same time, it allows your body to rebuild its immune system and be healthier. 

Can healthy people get seriously ill from the flu?

While healthy people generally recover from the flu without major complications, severe illness can occur in anyone. Though the risk is lower, previously healthy individuals have experienced serious complications from influenza infection. This is why prevention and appropriate medical care matter for everyone, not just those in high-risk groups.

Conclusion

Understanding what causes flu and how it spreads empowers you to protect yourself and your loved ones more effectively. By recognizing the role of influenza viruses and understanding transmission methods, you’re better equipped to navigate flu season safely in the Philippines.

Remember, prevention is a simple, yet effective first line of defense against the threat of flu. If you’ve been infected, and need immediate doctor consultation, book an online consultation with a flu doctor on NowServing!

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Alamin ang mga OTC medicine, home remedy, at kailan dapat magpatingin sa doctor sa aming gabay: Gamot sa Trangkaso: Paracetamol, Antiviral, at Home Remedy.

The post What Causes Flu and How Does the Flu Virus Spread appeared first on NowServing Health.

These symptoms can vary dramatically from person to person and across different age groups. What presents as a mild fever in a healthy adult might signal a dangerous complication in young children or elderly family members. Discover more details about the influenza outbreak Philippines symptoms, especially with the current flu season in the Philippines. Let’s begin!

What is a Seasonal Flu?

Seasonal flu or seasonal influenza is one of the common health problems that affects the respiratory health of people of all ages. It occurs when contagious influenza viruses are airborne, which can be inhaled by healthy people, leading to the cold symptoms escalating to flu. This illness commonly occurs in the Philippines during the rainy seasons.

This type of serious illness is often dismissed by Filipinos due to mild influenza symptoms in the Philippines

• cough
• sore throat
• fever

Such symptoms commonly appear 1-4 days after exposure. Thus, the importance of getting an influenza vaccination is a must.

Read this related blog to identify the vital vaccines to build-up your child’s immune system against infectious diseases.

The Classic Flu Symptoms in the Philippines

As mentioned, when you have the flu, your body reacts to it, which can be recognized as symptoms. These symptoms are signs of the body’s immune response against an infection.

Here are the common flu symptoms:

Fever and Chills

A sudden high fever, often 38°C (100.4°F) or higher, is one of the hallmark signs of influenza. Unlike other illnesses where fever builds gradually, flu-related fever typically spikes quickly with intense chills and sweating. You might find yourself piling on blankets one moment and throwing them off the next.

Read this article to manage fever through medication

Body and Muscle Pain

Another common symptom is the aching sensation throughout your body—especially in your back, arms, and legs. This muscle pain can be severe enough to make even simple movements uncomfortable.

Dry Cough and Nasal Problem (Stuffy or Runny Nose)

Meanwhile, flu can attack the respiratory system, leading to several uncomfortable symptoms. These include a dry cough, stuffy nose or runny nose with nasal discharge, and chest discomfort that worsens with coughing.

Headache and Fatigue

If you have a fever, most likely you’ll experience headache and fatigue. These symptoms are common due to the feeling of tiredness while the body fights against the virus. You can experience total depletion of energy, making it difficult to do your daily activities.

Influenza Symptoms Across Different Age Groups

While most people experience these symptoms, it is important to remember that there can be varying symptoms. There are cases wherein an adult patient can experience manifestations of symptoms that can be dangerous to child patients. That’s why being familiar with flu symptoms is crucial to manage the illness better.

Flu Symptoms in Young Children

Young children, especially those under five years old, face unique challenges with the flu. Their developing immune systems and inability to clearly communicate how they’re feeling make monitoring them closely essential.

Watch for these signs in your little ones:

• high fever (often above 39°C or 102°F) with increased fussiness
• decreased appetite and refusal to eat or drink
• unusual sleepiness or difficulty waking
• rapid or labored breathing
• bluish skin color especially around the lips
• dehydration signs like reduced urination.

If your child becomes unresponsive, has difficulty breathing, or the fever persists beyond three days, seek immediate medical attention.

Flu Symptoms in Adults

Healthy adults typically experience the full range of flu symptoms but usually recover without complications. However, high-risk adults should monitor their symptoms carefully (e.g., those with weakened immune system, chronic health conditions, or pregnant women).

For most adults, symptoms follow a predictable pattern:

• sudden onset of fever and chills,
• respiratory symptoms like runny nose, dry cough, etc.
• body aches.

The acute phase typically lasts 3 to 7 days, while cough and fatigue can persist for 2 weeks or longer. Visit a doctor for medical assistance and proper management of the symptoms.

Flu Symptoms in the Elderly

Older adults, particularly those over 65, face the highest risk of flu complications. Their symptoms might present differently than in younger people.

In the elderly, watch for the following symptoms of the flu:

• confusion or sudden changes in mental status
• worsening of existing chronic conditions like diabetes or heart disease
• weakness and increased fall risk
• lower-than-expected fever or even absence of fever
• difficulty breathing or shortness of breath

The elderly often have a diminished immune response, meaning symptoms might be less obvious while the infection is actually more dangerous. At the same time, they’re at a higher risk to develop serious problems due to a low immune system. When in doubt, always choose to visit an infectious disease doctor for health assessment and consultation.

Warning Signs That Require Immediate Medical Attention

Severe Flu Symptoms

While most people recover from the flu at home with rest and fluids, certain symptoms signal serious complications. These warning signs mean it’s time to stop monitoring and start seeking help.

• Difficulty Breathing or Shortness of Breath – If you or a family member experiences chest pain, pressure in the chest, or struggles to catch their breath, this could indicate pneumonia or other severe respiratory complications. Don’t wait—seek medical care immediately.
• Persistent High Fever – A fever that remains above 39°C (102°F) for more than three days despite medication suggests a possible bacterial infection or flu complications. A fever that improves and then returns with worse symptoms also requires evaluation.
• Severe Dehydration – Signs include extreme thirst, very dark urine or absence of urination, dizziness when standing, and dry mouth. Dehydration becomes dangerous quickly, especially in young children and elderly patients.
• Neurological Symptoms – Confusion, seizures, severe headache with stiff neck, or difficulty waking up are emergency symptoms. These could indicate flu-related neurological complications.
• Worsening of Chronic Illness- If you have asthma, diabetes, heart disease, or other chronic conditions that suddenly worsen during the flu, contact your healthcare provider promptly.

How to Protect Your Family from the Flu

While this article focuses on recognizing flu symptoms, prevention remains your best defense. Here’s what you can do to protect yourself and your loved ones.

• Get Vaccinated – The annual flu vaccine is your strongest protection against seasonal influenza. While it doesn’t guarantee you won’t get the flu, it significantly reduces the risk of flu complications and severe illness. Check out adult vaccinations and children vaccinations for influenza vaccine
• Practice Good Hygiene – Wash hands frequently with soap and water, cover coughs and sneezes with your elbow, avoid touching your face especially your eyes, nose, and mouth, and stay away from people who are sick.
• Boost Your Immune System – Get adequate sleep (7-9 hours for adults), eat nutritious foods rich in vitamins and minerals, exercise regularly to maintain overall health, and manage stress through relaxation techniques.
• Create a Healthy Home Environment – Ensure good ventilation in living spaces, regularly clean frequently-touched surfaces, and keep sick family members isolated when possible.

Visiting A Doctor for Flu

Whether you need flu vaccination or in need of doctor check-up to manage those symptoms, you must visit an infectious disease doctor.

Here’s how you can find an infectious disease doctor near you using NowServing.

• Visit the infectious disease page by accessing this link or open the NowServing app
• Check the list of infectious disease doctors in the Philippines, and choose your preferred doctor
• Schedule an appointment by tapping the “Book Appointment” button
• Wait for the doctor to approve your session

Take note that you can also visit a type of doctor that best suits you. For instance, if the patient is a child, then visiting a pediatric doctor is recommended. Meanwhile, an older adult patient may benefit more if they visit a doctor specializing in geriatric medicine or palliative care.

Frequently Asked Questions (FAQs) About Symptoms of Flu

What is the difference between COVID-19 symptoms and flu symptoms?

While there are similar symptoms between these infectious diseases, it is important to remember that COVID-19 includes loss of taste or smell. Patients with flu don’t experience such symptoms.

Can antibiotics treat the flu?

No, antibiotics don’t work against influenza viruses because the flu is a viral infection, not a bacterial infection. However, your doctor might prescribe antiviral medications like oseltamivir if you’re seen within the first 48 hours of symptom onset. Antibiotics are only prescribed if you develop a secondary bacterial infection like pneumonia.

How long am I contagious because of the flu?

You’re most contagious during the first 3-4 days after your flu symptoms begin. However, you can spread the virus from one day before symptoms start until about 5-7 days after becoming sick. This is why staying home from work or school when you’re sick is so important.

Should I go to the emergency room if I have the flu?

For typical flu symptoms, the emergency room isn’t necessary. Most people can manage at home with rest, fluids, and over-the-counter medications. However, go to the ER if you experience severe symptoms like difficulty breathing, chest pain, sudden dizziness, confusion, or severe vomiting. For non-emergency concerns, consider an online consultation first or book an immediate online consultation using the on-demand doctor consultation of NowServing.

What is the difference between the seasonal flu symptoms and super flu symptoms Philippines in 2026?

Super flu in 2026 is a health risk announced by the Department of Health (DOH) in the first week of Jan. While it is considered a super flu, take note that its symptoms are still the same as the seasonal flu that occurred previously from July of 2025 onwards. There are super flu cases in the Philippines, but only a number of cases were recorded. These patients contracted the new variant of flu virus, subclade K or H3N2.

Conclusion

Recognizing flu symptoms early and knowing which signs require medical attention can make a significant difference in your recovery. With seasonal flu affecting most Filipinos today, it’s best to be aware of the potential threat that this condition brings.

Whether you need guidance on managing symptoms at home or suspect you need medical intervention, modern healthcare options make getting care easier than ever. Get the medical care you need to manage your flu symptoms today by consulting a cold & flu doctor or an infectious disease specialist.

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