Flu season starts in the fall around October time and persists until the end of March. February is when infections are most likely, with December and January just behind.
Getting the flu once is bad enough. But contracting it a second time in a single season is unthinkable. In this post, we ask whether it can happen, how likely it is, and what you should do if you get sick.
Is it possible to get the flu twice in a season?
Because of the way the flu virus works, it is possible to get it twice in a row. But, the chances of it happening are rare.
There are four main types of flu viruses: A, B, C, and D. In most flu seasons, A and B are dominant. If you get the flu from either of these, you are unlikely to develop it again. However, if you catch type C or D, the risk of developing a second infection goes up substantially. That’s because these produce different antibodies.
Here’s how it works. When you catch the flu, your body develops specific antibodies against that strain. Therefore, if you catch strain A, you are protected against it.
In most flu seasons, developing antibodies against either A or B will protect you from both of them. However, if you catch flu type C or D, you may not develop antibodies against types A and B. Because of this, the likelihood of developing a second infection goes up substantially.
Even so, the overall chances of getting the flu twice in a season is extremely low. If you get sick a second time, it is usually another type of infection, not the flu.
Can you get the same flu strain twice?
Getting infected with the same flu strain is rare, but it can happen, even in the same season. For instance, if you catch influenza type A in November, you can become infected with an identical virus in December that same year.
Reinfection with the same strain means that your body didn’t produce enough antibodies to defeat it the first time around. Bad luck can be a cause but conditions that compromise the immune system, such as HIV, are more likely.
How to prevent seasonal flu?
The best way to protect yourself against seasonal flu is to get vaccinated. Vaccines give your body the antibodies it needs to fight flu viruses, once they arrive.
Even so, there are other strategies you can use. One option is to take vitamin D supplements in the winter. Research shows that these significantly reduce the risk of influenza infection.
You can also avoid close contact with other people, particularly indoors. Flu spreads in droplets in the air. If you are out of range of these, the likelihood of contracting an infection goes down significantly. Other strategies include regularly washing your hands in soap and warm water, and avoiding touching your eyes, nose, or mouth.
You should also practice other healthy habits. While they won’t eliminate the risk of flu infection entirely, they may reduce the severity of symptoms. Consider becoming more physically active, eating a healthier diet, drinking more fluids, managing your stress, and getting plenty of sleep.
How to treat the flu?
You can treat most flu cases at home. If you get infected, stop working, rest, and take on plenty of fluids. From the onset of symptoms, it usually takes one to three weeks to recover. During this time, your body’s immune system starts making the antibodies necessary to eliminate the infection.
To assist in recovery, rest during the day, avoid stress and eat plenty of healthy food. Do not exercise. If you can get other people to take over responsibilities for you, such as child care, do so.
Some flu symptoms can be painful. Therefore, physicians recommend over-the-counter painkillers such as ibuprofen and acetaminophen.
Flu-related dehydration is also a risk. Therefore, make sure that you take plenty of juices, soups, and warm drinks throughout the day. These will help your immune system fight infection.
When to see a doctor?
While the vast majority of people survive the flu without complications, it is still a dangerous disease (which is one of the reasons governments strongly recommend vaccinations). It can also lead to secondary complications, such as pneumonia.
If you are over the age of 50, tell your doctor that you have the flu, even if your symptoms seem mild. Monitoring your progress minimizes the risk of complications developing. You should also seek medical attention if you are pregnant, have HIV/AIDS or cancer, or have another chronic condition, such as diabetes or kidney disease.
If you are a younger adult, you should go to your physician for a checkup if you develop any severe symptoms. These include a sore throat that makes it painful to swallow, difficulty breathing, or coughing up large quantities of green or yellow mucus. Feeling faint is also a sign of severe disease, requiring medical attention.
If you have a child with the flu, you should take them to the doctor’s office or emergency room if you notice their skin looking more blueish, rapid or labored breathing, or failing to wake up when prompted. Babies that are too irritated to be held at all should also be taken for a checkup.
If doctors believe that the flu is severe, they may prescribe antivirals, such as peramivir and oseltamivir. These drugs assist the immune system and help to shorten the duration of symptoms.
Get help from an online doctor
If you or your child has the flu, you can get help from one of our online doctors.
If symptoms are severe, you should contact our virtual urgent care team. They can provide you with immediate assistance and issue any prescriptions that you might need.
- You can get flu twice in a season because there are multiple strains, but it is rare.
- Getting the same flu strain twice is even rarer, but is possible if your body fails to generate sufficient antibodies to prevent reinfection.
- You can treat most flu at home. However, if you develop severe symptoms, such as difficulty breathing, consult a doctor.
- Flu Season. Centers for Disease Control and Prevention. Available from: https://www.cdc.gov/flu/about/season/flu-season.htm
- Reinfection of Identical Influenza Virus May Not Be Rare. Consultant360. Available at: https://www.consultant360.com/exclusive/infectious-diseases/influenza/reinfection-identical-influenza-virus-may-not-be-rare
- Mitsuyoshi Urashima, Takaaki Segawa, Minoru Okazaki, Mana Kurihara, Yasuyuki Wada, Hiroyuki Ida, Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren, The American Journal of Clinical Nutrition, Volume 91, Issue 5, May 2010, Pages 1255–1260, https://doi.org/10.3945/ajcn.2009.29094
- Healthy Habits to Help Protect Against Flu. Centers for Disease Control and Prevention. Available from: https://www.cdc.gov/flu/prevent/actions-prevent-flu.htm
- Ada, G.L., Jones, P.D. (1986). The Immune Response to Influenza Infection. In: , et al. Current Topics in Microbiology and Immunology. Current Topics in Microbiology and Immunology, vol 128. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-71272-2_1
- Anne Moscona. Medical Management of Influenza Infection.Annual Review of Medicine 2008 59:1, 397-413. Available from: https://doi.org/10.1146/annurev.med.59.061506.213121
DrHouse articles are written by MDs, NPs, nutritionists and other healthcare professionals. The contents of the DrHouse site are for informational purposes only and are not a substitute for professional medical advice, diagnosis, or treatment. If you are experiencing high fever (>103F/39.4C), shortness of breath, difficulty breathing, chest pain, heart palpitations, abnormal bruising, abnormal bleeding, extreme fatigue, dizziness, new weakness or paralysis, difficulty with speech, confusion, extreme pain in any body part, or inability to remain hydrated or keep down fluids or feel you may have any other life-threatening condition, please go to the emergency department or call 911 immediately.