Flu symptoms (trangkaso): home care and when to see a doctor

Flu, or influenza, is an infection of the nose, throat and lungs caused by a virus. In Filipino it is called trangkaso. Symptoms usually start about 2 days after you catch the virus, but it can take from 1 to 4 days.

Flu symptoms come on suddenly, often within a few hours:

• fever, often with chills
• a dry cough
• a sore throat
• a headache
• muscle and joint aches
• feeling very tired, weak or exhausted
• a runny or stuffy nose
• poor appetite and trouble sleeping

Children may also vomit, have diarrhea or ear pain, or just seem less active than usual. Not everyone with flu has a fever.

The cough can be strong and can last 2 weeks or more, even after the fever is gone. Flu can also make long-term illnesses such as asthma worse.

Only a test can tell for sure, but these clues help:

• Flu vs cold. A cold builds up over a day or two, stays mostly in the nose and throat, and rarely stops your day. Flu hits within hours, with fever and body aches, and often leaves you too exhausted to work. See our common cold guide.
• Flu vs COVID-19. They share many symptoms. A nose or throat swab test can tell them apart.
• Flu vs dengue. In the Philippines, a fever with a severe headache, pain behind the eyes, muscle and joint pain, vomiting or a rash can be dengue rather than flu. Dengue needs its own check-up and has its own warning signs. See dengue symptoms and warning signs.
• "Stomach flu" is not flu. Vomiting and diarrhea without a cough or body aches are usually gastroenteritis, an infection of the gut.

Not sure what you have? Ask our free AI symptoms guide.

Most healthy people get better in about a week. The fever usually lasts 3 to 4 days, sometimes up to 8. The cough and tiredness can linger for weeks.

Flu is very contagious, most of all in the first 5 days after you catch it, and for a few days after you feel better. It spreads in droplets when a sick person coughs, sneezes or talks. Germs from coughs and sneezes can also live on hands and surfaces for up to a day.

Going back to work or school. Wait until you have had no fever for a full day without fever medicine, and your symptoms have been improving for a day. For the next 5 days, wear a mask around others and avoid crowds. If the fever comes back, stay home again.

Flu is caused by influenza viruses. Two types cause the outbreaks people get every year:

• Influenza A. The kinds now spreading in people are H1N1 and H3N2. Only influenza A is known to cause pandemics, like the H1N1 pandemic of 2009.
• Influenza B. It causes the same kind of illness and is cared for the same way.

Flu viruses keep changing, so the vaccine is updated every year.

Flu in the Philippines. In the tropics, flu can happen at any time of year. A study of national surveillance data from 2006 to 2012 by the Research Institute for Tropical Medicine (RITM), the DOH's national influenza center, found that flu cases rise from June to November. In those years, that was the rainy season and the start of the school year.

Some people are more likely to have problems such as pneumonia:

• children under 5, especially those under 2
• adults 65 and older
• pregnant women, and women who gave birth in the last 2 weeks
• people with asthma or another lung disease, diabetes, heart, kidney or liver disease, or another long-term illness
• people with a weak immune system, for example from HIV, chemotherapy or steroid medicines
• people with severe obesity

Less often, flu leads to swelling of the heart or brain, seizures or sepsis (a severe reaction of the whole body to infection). Pregnant women can get very sick very fast, even when the first symptoms are mild.

If you or your child is in one of these groups, see a doctor as soon as flu symptoms start. Antiviral medicine works best when it is started within 2 days.

Most people with flu get better at home. These steps help:

• Rest. Stay home and sleep as much as you need while you have a fever or are too sick for your usual work.
• Drink plenty of fluids, such as water, sabaw (soup) or warm salabat. Your pee should be light yellow or clear. If it is dark, drink more.
• Ease fever and aches with paracetamol, following the label. Your fever does not have to come all the way down for you to feel better.
• Soothe a sore throat with warm drinks, and for adults, cough drops or throat sprays. Skip cigarettes and alcohol.
• Protect your household. Stay in one room if you can, don't share cups, spoons or towels, wear a mask when others are near, and open the windows. Cough or sneeze into a tissue or your elbow, and wash your hands often.

If you can't keep fluids down or are peeing much less than usual, see a doctor today. Keep watching for warning signs. For advice from a person, ask a nurse or book a call.

Paracetamol is the usual first choice for fever and aches. Follow the label, and for a child, use a product meant for their age.

• Think of dengue first. In the Philippines, a fever in its first days can be dengue. Ibuprofen and aspirin raise the risk of bleeding in dengue, so avoid them unless a doctor has ruled dengue out. After that, ibuprofen can also ease fever and aches in adults.
• Avoid aspirin for flu. It can cause stomach bleeding. Never give aspirin to children or teenagers: it can cause Reye syndrome, a rare but serious illness.
• Many flu tablets already contain paracetamol. Don't take them with plain paracetamol, because it is easy to take too much.
• No ibuprofen for babies under 6 months unless a doctor says so.
• Pregnant? Paracetamol is usually safe in pregnancy, but ask your doctor or midwife before taking any cold or flu medicine.

Antiviral medicines, such as oseltamivir, act on the flu virus itself. They need a doctor's prescription and are mainly for people who are very sick or at higher risk, including pregnant women. They work best when started within 2 days of the first symptoms, but a doctor may still give them later. They can shorten the illness by about a day and lower the risk of complications. They don't replace the yearly vaccine.

Antibiotics don't work against flu, because flu is caused by a virus. A doctor may prescribe them only if a bacterial infection, such as some kinds of pneumonia, follows the flu.

Children catch and spread flu easily, and children under 5 can get very sick.

• Give a fever medicine only if your child is distressed or uncomfortable.
• Don't give over-the-counter cough and cold medicines to children under 4. For ages 4 to 6, ask a doctor first.
• Keep your child home from school until they are well.
• Watch for confusion or strange behavior, which can happen with flu in children and teenagers. Get help right away if you see it.

See the emergency signs under when to get help now, and our guides on fever in babies and children and cough remedies.

• "Nabasa ng ulan kaya natrangkaso." Rain by itself does not cause flu. A virus passed from person to person does. Cases do rise from June to November, during the rainy season, but the cause is the virus.
• Binat. Resting until you are well is wise. But if you feel much sicker or short of breath after you started to improve, get checked, because flu can lead to pneumonia.
• Salabat and calamansi. Warm drinks soothe the throat and help you drink enough. They don't replace a check-up when warning signs appear.
• "The flu shot gives you flu." It can't, because the shot contains killed virus. A sore arm, headache, muscle aches or a mild fever for a day or two can happen.

• Barangay health station or rural health unit (RHU). Your health center can check you and refer you to a hospital if needed.
• PhilHealth YAKAP. In October 2025, PhilHealth urged members to go to their YAKAP clinic as soon as flu-like symptoms start. As of mid-2025, YAKAP covers check-ups, the lab tests your YAKAP doctor orders, and the medicines your YAKAP doctor prescribes from PhilHealth's GAMOT list, up to ₱20,000 a year. Covered services are free at accredited YAKAP clinics, but private YAKAP clinics may collect up to ₱900 per person for the whole year. You need to be registered with a YAKAP clinic first, for example through the eGovPH app or at a PhilHealth office. See our PhilHealth YAKAP guide.
• Emergency room. As of late 2025, PhilHealth's Outpatient Emergency Care Benefit covers patients rushed to the emergency room whose condition is classified as emergent or critical.
• Hospital stay. As of late 2025, PhilHealth pays a case rate of ₱12,870 for flu that needs a hospital stay. Complications such as pneumonia have their own packages: in PhilHealth's 2024 case rate list, moderate-risk pneumonia is ₱29,250.
• Malasakit Centers inside hospitals are one-stop desks where patients who cannot afford their bills can ask PhilHealth, PCSO and DSWD for help.

Find a health center, YAKAP clinic or hospital with our care finder.

A flu vaccine every year is the best way to prevent flu. Flu vaccines have been used safely for more than 60 years. You need a new one every year, because protection fades and the viruses change. Even if you still catch flu, the vaccine can make it less severe. Protection takes about 2 weeks to build up.

The WHO especially recommends a yearly flu vaccine for pregnant women, children 6 months to 5 years old, adults over 65, people with long-term illnesses and health workers. Anyone 6 months or older can be vaccinated, and the flu shot is recommended in pregnancy. Young children getting a flu vaccine for the first time may need a second shot a few weeks later. The health worker will tell you.

Timing in the Philippines. Because cases rise from June, RITM researchers recommend getting the Southern Hemisphere vaccine in April to May. A later shot still helps. Ask your health center, RHU or doctor whether they have flu vaccines and who can get one for free.

Everyday habits: wash your hands with soap, keep your hands away from your eyes, nose and mouth, avoid close contact with sick people, and stay home when you are sick.