When you think of the flu, symptoms like fever, fatigue, muscle aches, and a persistent cough likely come to mind. However, if you’ve experienced diarrhea along with your flu-like symptoms, you may be wondering whether the flu is responsible for your stomach upset or if you’ve contracted another illness altogether. While the flu is primarily a respiratory infection, diarrhea can sometimes be a symptom—especially in children. Understanding why this happens and how to manage flu-related diarrhea can help you recover more comfortably.

Influenza is a viral infection that primarily affects the respiratory system, but in some cases, it can also impact the digestive tract. This is more common in children, particularly those infected with influenza B. Studies suggest that 10% to 15% of children with influenza B experience gastrointestinal symptoms, including diarrhea and vomiting. While diarrhea is less common in adults, it can still occur, especially during flu seasons dominated by certain influenza strains, such as H1N1 and H3N2.

The exact reason why some people experience flu-related diarrhea is not well understood. Researchers believe it may be due to the virus affecting different parts of the body beyond the lungs, triggering an immune response that causes digestive symptoms. Additionally, fever and inflammation can disrupt gut function, leading to temporary digestive distress.

Is It the Flu or the Stomach Flu?

Many people mistakenly refer to viral gastroenteritis as the “stomach flu,” but it is not caused by the influenza virus. Instead, stomach flu is typically the result of infections from other viruses, such as:

Norovirus – The most contagious cause of viral gastroenteritis

Rotavirus – Common among children, peaking between April and December

Adenovirus – Affects individuals with weakened immune systems

Astrovirus – Causes mild gastrointestinal symptoms

Unlike influenza, which primarily affects the respiratory system, stomach flu attacks the digestive tract, leading to nausea, vomiting, and diarrhea. If your primary symptoms are digestive-related and you don’t have respiratory symptoms like cough or congestion, you may be dealing with viral gastroenteritis rather than influenza.

How Long Does Flu-Related Diarrhea Last?

Most flu symptoms, including fever, chills, and congestion, last between 2 and 5 days, though some can persist for up to 10 days. If diarrhea is a symptom of your flu, it usually follows the same timeline as other symptoms. However, in some cases, diarrhea may resolve earlier or linger slightly longer, particularly in children or individuals with weakened immune systems.

Managing Flu-Related Diarrhea at Home

While flu-related diarrhea can be uncomfortable, there are several steps you can take to manage symptoms and prevent complications like dehydration. Here’s how:

1. Stay Hydrated

Diarrhea can quickly lead to dehydration, especially when combined with fever. To maintain proper hydration, consider the following:

• Drink plenty of fluids such as water, clear broth, and electrolyte solutions like Pedialyte or Gatorade.
• Avoid alcohol and caffeine, as they can increase dehydration.
• Skip sugary drinks and milk until you recover, as these can sometimes worsen diarrhea.

2. Eat Easy-to-Digest Foods

Although no strict diet is necessary, choosing light, bland foods can be gentler on your stomach. The BRAT diet (Bananas, Rice, Applesauce, and Toast) is often recommended for temporary digestive distress. Other good options include:

• Plain crackers
• Cooked cereals
• White bread
• Simple broth-based soups

Avoid fried, fatty, or spicy foods, which may aggravate symptoms. Once you start feeling better, reintroduce a balanced diet with fiber-rich foods and proteins to restore gut health.

3. Consider Probiotics or OTC Medications

Over-the-counter probiotic supplements contain beneficial bacteria that may help restore gut balance. While they won’t necessarily stop diarrhea immediately, they can aid in recovery. Some people also find relief using anti-diarrheal medications like loperamide (Imodium), but these should be used with caution, particularly in children.

When Should You Consult a Doctor?

Most flu-related diarrhea resolves on its own, but medical attention may be necessary if:

• Symptoms persist longer than a week
• You experience severe dehydration (dry mouth, dark urine, dizziness)
• Diarrhea is accompanied by high fever (over 102°F) or bloody stools
• A child refuses to drink fluids or shows signs of lethargy

In these cases, a healthcare provider can assess whether additional treatment, such as IV fluids or antiviral medications, is necessary.

While diarrhea is not a hallmark flu symptom, it can occasionally occur, especially in children and during certain flu seasons. Understanding the difference between influenza and viral gastroenteritis can help you determine the best course of action. Managing flu-related diarrhea with hydration, light foods, and probiotics can ease symptoms and prevent complications. If symptoms worsen or persist, seeking medical attention is always the best approach.

Disclaimer: This article is for informational purposes only and should not be used as a substitute for professional medical advice. Always consult a healthcare provider for medical concerns.

While H3N2 flu cases are surging, one question that is being asked time and again is whether the old vaccines provide protection against this new variant. While the new strain of virus was detected after the vaccine had already undergone its update, the good news is that it still provides the best protection against the illness from H3N2 strains.

The real reason why concerns are prompted about the effectiveness of the seasonal vaccine is because the virus underwent more mutation than scientists expected over summers. This mutant is called the 'subclade K' or 'super flu'. While it is true that most cases this season are of the 'super flu' strain, experts say that the flu jab is still offering a strong protection.

How Effective Is The Flu Jab Against The New Flu Strain?

"The vaccine remains the most effective means to prevent disease. We still want to encourage people to get the vaccine," said Professor Antonia Ho, Professor and Honorary Consultant in Infectious Diseases at the University of Glasgow. Experts have stressed enough on the immunity that one can receive from the vaccine that that these flu jab remain the best defense against the flu, even though the current strain circulated may have drifted away from the strain included in this year's jab.

Data from the UK Health Security Agency (UKHSA) also show that vaccines is performing as expect, despite the emergence of subclade K.

How Is The Flu Jab Developed?

Every year, experts from the World Health Organization, the Centers for Disease Control and Prevention, and other global health agencies closely track flu trends around the world. They study which strains are spreading and use that data to predict which ones are most likely to dominate the upcoming flu season. The annual flu vaccine is then designed to protect against three or four of those strains.

It’s also worth understanding that more than one influenza A strain usually circulates at the same time. So even if the vaccine is not an exact match for a newer H3N2 strain, it still protects against other common flu viruses, which matters, notes Stony Brook Medicine.

When a new variant emerges, the flu shot can still offer what doctors call cross-protection. In simple terms, the antibodies your body makes after vaccination can recognize similar flu viruses and respond to them. You might still get sick, but the vaccine greatly lowers the chances of severe illness, hospitalization, or worse.

The vaccine offers protection against both types of influenza, including A and B.

Also Read: The New Flu Strain Emerged Too Late For Vaccines, And It Is Already Causing Outbreaks

Is There Any Difference Between Influenza A and B?

Influenza A

Influenza A changes quickly. Its genetic makeup shifts often, which is why new strains keep emerging and why it can trigger large outbreaks. It usually shows up early in the flu season and has been responsible for every major flu pandemic recorded so far.

Influenza B

Influenza B is more stable and does not change as rapidly from year to year. It tends to appear later in the season, often peaking in late winter or spring. While it does not cause pandemics, it can still lead to serious illness, particularly in children and young adults.

When talking about fertility in routine practice, we usually refer to the World Health Organization’s guideline of roughly 15 million sperm per millilitre (and around 39–40 million total per ejaculate) as the lower boundary of “normal.”

But the count alone doesn’t tell the full story. The quality of sperm, their motility, shape, and the couple’s overall reproductive health are equally important. We got in touch with Dr. Meenakshi Priya, Clinical Director & Fertility Specialist, Nova IVF Fertility, Coimbatore, who told us more about the same.

What Is The Normal Sperm Count To Get Pregnant?

Dr Meenakshi said, “Think of sperm count like lottery tickets. More tickets (higher count) give you better odds, fewer tickets lower your chances — but even one well-functioning ticket (a motile, properly shaped sperm) can win.”

That’s why fertility clinics look at several factors: concentration, total number, progressive motility (whether sperm swim forward), and morphology (shape). The WHO manual provides the standard method and cut-offs used worldwide in labs, serving as the referee for semen analysis.

However, numbers matter clinically. Research over decades shows fertility starts to drop gradually below about 40 million/ml (or in older studies, 40 million total per ejaculate was a useful marker). The WHO threshold of 15 million/ml marks the lower edge of normal — values between 15 and 40 are a “grey zone,” where conception is possible but may take longer. So a man with 12 million/ml isn’t infertile, but the couple might need help like IUI or IVF depending on other factors.

But don’t get fixated on one number. A “normal” semen report is a combination of factors:

• Concentration ≥15 million/ml

• Total sperm count ≥39–40 million per ejaculate

• Progressive motility roughly >30%

• Normal morphology about 4% (Kruger criteria)

What Changes A Sperm Count?

Lifestyle and health have a big impact on sperm. Smoking, heavy drinking, extra weight, prolonged heat exposure (saunas, hot tubs, tight underwear), certain medications, recent fevers, and conditions like varicocele or hormonal imbalances can all lower the numbers.

The good news? Most of these are reversible. Dr Meenakshi said, “Quitting smoking, reducing alcohol, losing a bit of weight, avoiding hot tubs for a few months, and treating infections can improve sperm.” Remember, sperm take time to renew but it usually takes 2–3 months of healthier habits for improvements to appear in a report. Be patient; your body is making changes even if you don’t see results immediately.

When To Be Concerned And Consult A Doctor?

If semen analysis repeatedly shows very low sperm (oligozoospermia), no sperm (azoospermia), poor motility, or if a couple has been trying for a year (or six months if the woman is over 35) without success, it’s time to consult a specialist. One abnormal test isn’t the final word — tests are usually repeated, and a more thorough assessment may include hormone checks, ultrasounds, or genetic tests if needed.

Dr Meenakshi said, “Sperm count gives a headline, not the full story. It’s a useful screening tool, but fertility decisions are personal. If you’re concerned, get a proper semen analysis and speak with a fertility specialist — many fertility issues are treatable, and acting early makes a real difference.”

Norovirus, often called the stomach bug, has returned. Between August 1 and December 11, health officials recorded 268 norovirus outbreaks, with numbers climbing steadily as winter travel increases and more people spend time indoors. The virus triggers stomach-related symptoms such as nausea, vomiting, diarrhea, and abdominal pain or cramping.

Some people also develop fever, headaches, and body aches. Although case numbers are not rising as sharply as flu, doctors remain concerned because norovirus spreads extremely easily. Making matters worse, norovirus is difficult to kill. Many of the common precautions used against flu and COVID offer little protection against this so-called winter vomiting bug.

How Contagious Is the Norovirus?

Norovirus is among the most infectious viruses doctors deal with. “It can tear through a household and then circle back, with people repeatedly passing it to each other,” says Amy Edwards, MD, associate professor of pediatrics at Case Western Reserve University School of Medicine in Cleveland, Ohio, who specializes in infectious diseases. “It also spreads very quickly in crowded, closed settings like cruise ships.”

While contaminated surfaces can transmit norovirus, doctors say person-to-person spread is most common. An infected person can pass on the virus even before symptoms appear, throughout the illness, and after they start to feel better, Jennings warns.

What to Do If You Get Norovirus?

For most people, norovirus symptoms ease within a few days, according to Jennings. However, the illness can be more serious for those with weaker immune systems, including young children, older adults, and people with certain health conditions.

If you think you have norovirus, focus on staying well hydrated. Ongoing vomiting can quickly lead to fluid loss and electrolyte imbalance. To prevent nausea from getting worse, Jennings recommends taking small sips of clear fluids like water, ginger ale, or coconut water.

Most importantly, seek medical care right away if you become dehydrated or if diarrhea lasts for weeks. Fischer explains that dehydration may cause sunken eyes, less frequent urination, dry skin and mouth, and extreme tiredness.

Common Norovirus Symptoms That You Should Be Aware Of

Norovirus symptoms often come on suddenly and may include:

• Nausea
• Vomiting
• Stomach pain or cramps
• Watery or loose diarrhea
• General feeling of illness
• Mild fever
• Muscle aches

Symptoms usually begin 12 to 48 hours after exposure and last for one to three days. Even after recovery, people can continue shedding the virus in their stool for weeks. In some cases, especially among those with other medical conditions, shedding can continue for months. Some people infected with norovirus never develop symptoms at all. Even so, they can still spread the virus to others.

Norovirus Causes

Norovirus spreads very easily from one person to another. Because it is highly contagious, an infection can pass quickly through homes, schools, or other shared spaces. The virus is released through stool and vomit, and a person can spread it from the moment symptoms begin until several days after they feel better. Norovirus can also survive on surfaces and objects for days or even weeks.

You can catch norovirus by:

1. Eating food that has been contaminated
2. Drinking unsafe or contaminated water
3. Touching your mouth after your hands have come into contact with a contaminated surface or object
4. Having close contact with someone who is infected with norovirus

Norovirus is especially hard to get rid of because it can survive extreme hot and cold temperatures and is resistant to many common disinfectants.