Flu (influenza) in Puerto Rico: symptoms, treatment and video visits

Flu symptoms

Flu usually starts abruptly, unlike a cold, which comes on gradually. The most common symptoms are:

• Fever or feeling feverish, with chills
• Cough
• Sore throat
• Stuffy or runny nose
• Muscle or body aches
• Headache
• Extreme tiredness
• Vomiting and diarrhea, more common in children

How long the flu lasts and home care

Fever usually lasts 3 to 4 days; other symptoms improve in 7 to 14 days, and the cough and tiredness can linger for weeks. Most healthy people do not need to see a doctor.

Rest, drink plenty of fluids, and use acetaminophen or ibuprofen for fever and aches as the label directs. Antibiotics don’t work on flu, because it is caused by a virus.

Stay home while you are sick. The CDC says you can go back to normal activities when, for at least 24 hours, your symptoms are getting better and you have had no fever without fever-reducing medicine. For the next 5 days take extra care: wash your hands, wear a mask around others and avoid close contact. If you need a doctor’s note for work, the doctor can write one after a real visit.

Flu antivirals: who needs them and why timing matters

Flu antivirals are prescription medicines. They work best when started within two days of the first symptoms, can shorten the illness by about a day, and may reduce some complications.

The CDC recommends early treatment for people at higher risk of complications. Most healthy people with mild symptoms don’t need them, so if you are in a risk group, get assessed early in an online doctor visit. If appropriate, the doctor can prescribe medication, and she will check it against what you already take. We do not prescribe controlled substances.

Who is at high risk from flu

Get assessed early if you have flu and are in one of these groups:

• Adults 65 and older.
• Children under 5, especially under 2.
• Pregnancy.
• Asthma or other lung disease.
• Heart disease, diabetes, or kidney or liver disease.
• A weakened immune system from illness or medicines.
• Severe obesity, or neurological or blood conditions such as sickle cell disease.

Flu or COVID? Only a test can tell

Flu and COVID-19 share almost every symptom: fever, cough, shortness of breath, tiredness, sore throat, congestion, aches, and even vomiting or diarrhea. The CDC says you cannot tell them apart by symptoms alone; testing is needed.

Some differences: flu symptoms usually appear 1 to 4 days after infection, COVID-19 symptoms 2 to 5 days after (and up to 14). Loss of taste or smell is more typical of COVID-19. COVID-19 home tests are sold over the counter at pharmacies. If yours is positive, see COVID-19. You can also have both infections at once.

In Puerto Rico: flu or dengue?

In Puerto Rico, a fever can also be dengue. The CDC describes dengue as fever with aches (behind the eyes, or in the muscles, joints or bones), nausea, vomiting or a rash. Puerto Rico had 6,291 confirmed dengue cases in 2024, and people aged 10 to 19 were the most affected group, according to a CDC report.

If dengue is possible, do not take aspirin or ibuprofen; the CDC recommends acetaminophen. Dengue warning signs usually begin 24 to 48 hours after the fever goes away and mean going to the ER: belly pain, vomiting 3 or more times in 24 hours, bleeding from the nose or gums, blood in vomit or stool, or extreme tiredness or restlessness. Read dengue warning signs.

Flu in children

Children under 5, and especially under 2, are at higher risk of flu complications. Prescription antivirals can be a safe and effective treatment for children, with the dose based on age and weight. The American Academy of Pediatrics (AAP) advises calling a doctor within 24 hours of the first symptom if your child is under 5 or has asthma, diabetes, a heart condition or another chronic illness.

Never give aspirin to a child or teen with flu, because of the risk of Reye syndrome. Ibuprofen can be used from 6 months, but not if a child is dehydrated or vomiting continuously. Over-the-counter cough and cold medicines are not recommended under age 4.

Get care right away if your child is breathing fast or with difficulty, has ribs pulling in with each breath, has gray or bluish lips or skin, hasn’t urinated in 8 hours, is not alert, has a seizure, has a fever above 104 °F (40 °C), or gets better and then worse. Any fever in a baby under 12 weeks is urgent. We see children from 6 months; see video visits for children and fever in children.

Flu prevention and the flu vaccine

The best protection is a flu vaccine every year for everyone 6 months and older. We do not give vaccines: get yours from your own doctor, a pharmacy or a vaccination center.

Wash your hands with soap and water for at least 20 seconds, cover coughs and sneezes, and stay home when sick. The doctor is not a pediatrician and does not give vaccines, but she can advise you during a visit.

Frequently asked questions

How can I tell if I have the flu or COVID?

You can’t be sure from symptoms: both cause fever, cough, aches and tiredness. You need a test. COVID-19 home tests are sold at pharmacies; a flu test is done by a health care provider with a swab.

When should I take a flu antiviral?

Antivirals work best when started within the first two days of symptoms and are recommended mainly for people at higher risk of complications. They need a prescription; the doctor will assess whether one is right for you.

Can I see a doctor for the flu while visiting Puerto Rico?

Yes. Anyone who is physically in Puerto Rico during the visit can book, including visitors. A visit costs US$79, and we do not bill insurance.

Related pages

• Online doctor visit
• COVID-19
• Sore throat
• Sinus infection (sinusitis)
• Dengue warning signs
• Fever in adults
• Online doctor for kids
• Sick on vacation in Puerto Rico