Your Top Flu Questions Answered
January 12, 2026
The flu (influenza) is hitting hard this year, and affecting people throughout the country. The highly contagious respiratory illness causes symptoms ranging from fever and cough to runny nose and muscle aches.
For many, the flu is merely a nuisance that takes time to recover from, but for some, especially the very young, the elderly and those with underlying medical conditions, the flu can be deadly. Swapnil Patel, M.D., an internal medicine physician at Jersey Shore University Medical Center, answers some of the top flu questions he is routinely asked.
How Long Am I Contagious With the Flu?
Most people are contagious with the flu starting one to two days before symptoms appear. They generally remain contagious for five to seven days after symptom onset, with the highest risk of spreading the virus during the first three to four days of the illness.
“Viral shedding typically peaks early and then steadily declines. In otherwise healthy adults, the virus usually becomes undetectable within about a week,” he says.
Is the Flu Shot Effective Against the New Flu Strain?
Because flu shots are produced months before flu season begins, it can be challenging to match the flu vaccine perfectly to the strains that emerge each year. Although early reports raised questions about how well this season’s vaccine aligns with the new flu strain, Dr. Patel says a new report shows the vaccine is still effective.
“Despite this ongoing discussion, emerging data reinforces the idea that the vaccine remains effective, even against the newer circulating virus and is recommended to reduce influenza illness and severe outcomes,” says Dr. Patel.
What’s the First Symptom of Flu?
The flu typically begins abruptly, and the combination of fever and cough is the most predictive early symptom in adults during flu season. Early symptoms commonly include:
- Fever
- Cough
- Runny nose
- Muscle aches
- Fatigue
- Headache
- Sore throat
Dr. Patel stresses that symptoms can vary by age, with children being more likely to experience high fever, chills, headache, eye discomfort and occasionally diarrhea. People with chronic conditions or those who are hospitalized may be less likely to experience classic symptoms and may have shortness of breath or wheezing.
Can You Get the Flu Twice in One Season?
Although it’s rare, Dr. Patel says you can contract the flu twice in a single season.
“Reinfection is more common with different strains. Reinfection with the same subtype is very rare,” he says.
Can The Flu Pass To/From Dogs?
Yes, influenza can be transmitted between humans and dogs in both directions. However, transmission from dogs to humans has not been documented, whereas transmission from humans to dogs is well-established.
How Can You Prevent the Flu?
There are several ways to stay healthy and prevent the spread of the flu. Dr. Patel’s top suggestions include:
- Get vaccinated. If you haven’t gotten the flu shot, there’s still time. The Centers for Disease Control and Prevention (CDC) estimated that individuals who were vaccinated last season were 40 to 70 percent less likely to be hospitalized due to the flu.
- Avoid contact with sick people, and stay home if you are sick. The flu is highly contagious; the best way to avoid spreading the virus is to stay home while you recover.
- Wash your hands frequently for 30 seconds. You can also sing “Happy Birthday” twice to time it right.
- Avoid touching your face. Your face has many orifices and mucus membranes that are easy entry points for unwanted microbes.
Next Steps & Resources
- Meet our experts: Swapnil Patel, M.D.
- Make an appointment online with Dr. Patel or a doctor near you, or call 800-822-8905.
- Learn more about primary care at Hackensack Meridian Health.
The material provided through Healthier You is intended to be used as general information only and should not replace the advice of your physician. Always consult your physician for individual care.
