The flu (influenza) is hitting hard this year and affecting people across the country. This highly contagious respiratory illness causes symptoms ranging from fever and cough to runny nose and muscle aches.
For many, the flu is simply a nuisance that takes time to recover from, but for others—especially the very young, the elderly, and those with underlying medical conditions—it can be dangerous or even deadly. Swapnil Patel, M.D., an internal medicine physician at Jersey Shore University Medical Center, answers some of the top flu-related questions he is routinely asked.
How Long Am I Contagious With the Flu?
Most people are contagious starting one to two days before symptoms appear. They typically remain contagious for five to seven days after symptoms begin, with the highest risk of spreading the virus during the first three to four days of illness.
“Viral shedding typically peaks early and then steadily declines. In otherwise healthy adults, the virus usually becomes undetectable within about a week,” Dr. Patel explains.
Is the Flu Shot Effective Against the New Flu Strain?
Flu vaccines are produced months before flu season begins, which makes it difficult to perfectly match the vaccine to the strains that end up circulating—especially when new strains emerge. Although early reports questioned how well this season’s vaccine matched the new strain, Dr. Patel says updated findings show 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 the Flu?
The flu usually begins abruptly, and the combination of fever and cough is the most predictive early sign in adults during flu season. Common early symptoms include:
- Fever
- Cough
- Runny nose
- Muscle aches
- Fatigue
- Headache
- Sore throat
Dr. Patel notes that symptoms can vary by age. Children are more likely to experience high fever, chills, headache, eye discomfort, and occasionally diarrhea. Meanwhile, individuals with chronic health conditions or those who are hospitalized may not show the classic symptoms and may instead experience shortness of breath or wheezing.
Can You Get the Flu Twice in One Season?
Although it’s uncommon, Dr. Patel says it is possible to get 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 or From Dogs?
Yes—flu viruses can be transmitted between humans and dogs. However, transmission from dogs to humans has not been documented, while transmission from humans to dogs is well-established.
How Can You Prevent the Flu?
Dr. Patel recommends several steps to stay healthy and reduce the spread of influenza:
- Get vaccinated. If you haven’t gotten your flu shot yet, there’s still time. According to The Centers for Disease Control and Prevention (CDC), individuals 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’re sick. Because the flu spreads so easily, isolating yourself when ill is the best way to prevent transmission.
- Wash your hands frequently for at least 30 seconds. A simple way to time this is by singing “Happy Birthday” twice.
- Avoid touching your face. Your eyes, nose, and mouth are easy entry points for viruses and other microbes.