Causes and Spread
Influenza spreads mainly through respiratory droplets released when infected people cough, sneeze, or talk. It can also spread by touching contaminated surfaces and then the eyes, nose, or mouth. People are contagious beginning about one day before symptoms start and for several days afterward, which is why the virus moves quickly through households and workplaces.Symptoms
Unlike a common cold, flu symptoms usually come on abruptly:- Fever and chills: Often with temperatures of 100–104°F, though not everyone with flu has a fever.
- Body aches and headache: Muscle aches are typically prominent.
- Cough and sore throat: A dry cough may linger for weeks.
- Fatigue and weakness: Can last well beyond the other symptoms.
- Runny or stuffy nose: Sometimes with sneezing.
- Vomiting and diarrhea: More common in children than adults.
Complications
Most complications occur in higher-risk groups, but they can affect anyone:- Pneumonia: The most serious common complication, caused by the flu virus itself or by bacteria invading afterward.
- Worsening of chronic conditions: Flu can trigger asthma attacks, COPD flare-ups, and heart problems, and it makes blood sugar harder to control in people with diabetes.
- Sinus and ear infections: Common, milder complications.
- Dehydration: A particular concern for older adults in Florida's heat, since fever and poor intake add up quickly.
Diagnosis
During flu season, doctors often diagnose influenza from symptoms alone. Rapid tests using a nasal swab can confirm the diagnosis in about 15 minutes, which is helpful when the result would change treatment, when symptoms overlap with COVID-19, or when a household member is at high risk and might benefit from preventive antiviral medication.Treatment
For most healthy adults, rest, fluids, and fever reducers such as acetaminophen are the mainstays. Antiviral medications such as oseltamivir work best when started within 48 hours of symptom onset and can shorten the illness and reduce complications; they are especially important for older adults and people with chronic conditions such as asthma, COPD, diabetes, or heart disease. Antibiotics do not treat the flu because it is caused by a virus.Prevention
Yearly vaccination is the single best protection. Because circulating strains change, the vaccine is updated annually, and everyone 6 months and older is advised to receive it each fall. Adults 65 and older benefit from higher-dose or adjuvanted vaccines designed to produce a stronger immune response. Frequent handwashing, avoiding close contact with sick people, and staying home while ill also limit spread. In some situations — for example, a high-risk household member exposed to the flu — doctors may prescribe an antiviral preventively.When to Seek Immediate Care
Seek urgent medical attention for difficulty breathing, chest pain, confusion, persistent dizziness, inability to keep fluids down, or a fever that improves and then returns with a worse cough — the last can signal pneumonia developing after the flu. An annual wellness visit is a convenient time to get your flu shot and review your risk. Zimmer Medical Group's primary care team in St. Petersburg offers seasonal flu vaccination and prompt sick visits during flu season — schedule an appointment to stay protected.Getting Through Flu Season in Florida
Most flu is managed at home, and most of what goes wrong is a matter of timing: antivirals started too late, the return-to-work call made too early, and the vaccine put off until the season has already arrived. The points below are the ones that change outcomes.
Antivirals after the 48-hour window
The two-day rule applies to otherwise healthy adults. For anyone over 65, pregnant, or living with asthma, COPD, diabetes, or heart failure, oseltamivir is still worth starting later, because it reduces complications even when it no longer shortens the illness much, and anyone sick enough for the hospital is treated regardless of the day. The five-day course is finished even once the fever breaks.
Flu, COVID, and RSV are told apart by a swab
The three circulate together every winter and the treatments differ: Paxlovid for COVID-19, oseltamivir for influenza, and supportive care for RSV. A combined swab in the office answers the question in minutes, so calling early matters. Our cold, flu, COVID, and RSV comparison covers the differences.
The heart risk nobody mentions
The week after influenza carries a sharply raised risk of heart attack and stroke, most of all in people with coronary artery disease, because the inflammation of the infection destabilizes plaque and the fever strains the heart. It is why new chest pain or breathlessness during or just after the flu is treated as an emergency rather than as part of the illness.
Fever, fluids, and going back to work
Acetaminophen or ibuprofen eases fever and aches; aspirin is avoided in children and teenagers because of Reye's syndrome. Florida heat turns a fever into dehydration quickly, so fluids matter more than food for the first few days, and dark urine is the signal to drink more. You remain contagious until at least 24 hours after the fever has gone without fever reducers, which is the CDC's threshold for returning to work or school. A cough that lingers two or three weeks after the flu is expected; one still present at eight weeks is chronic cough and is evaluated separately.
Vaccine timing, and the other shot that matters
September or October is the right window here: protection takes about two weeks to build and wanes over the season, and Florida's activity often peaks after the New Year and can run into spring. It can be given at the same visit as a COVID or pneumococcal vaccine, and the pneumococcal vaccine matters because bacterial pneumonia after the flu is what most often puts older adults in the hospital. Egg allergy is no longer a reason to skip or modify the flu shot. Our adult vaccine checklist lists what is due at each age, and our pulmonary team follows anyone whose lungs have not recovered. The CDC and MedlinePlus publish patient guidance on treatment and prevention.
If you have flu symptoms and a chronic condition, or have not had this season's vaccine, schedule a visit; the antiviral window is short.