What is influenza (the flu)?

Influenza, commonly known as the flu, is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness, and at times can lead to hospitalization or even death.

How does the flu spread?

The flu spreads mainly through droplets made when people with the flu cough, sneeze, or talk. These droplets can land in the mouths or noses of people who are nearby. Less often, a person might get the flu by touching a surface or object that has the flu virus on it and then touching their own mouth, nose, or eyes.

What are the symptoms of the flu?

Common symptoms include fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills, and fatigue. Some people may also have vomiting and diarrhoea, though this is more common in children than adults.

How can the flu be prevented?

The best way to prevent the flu is by getting vaccinated each year. Other preventive measures include washing your hands often, avoiding close contact with sick people, and covering your mouth and nose with a tissue or your elbow when you cough or sneeze.

Can I get the flu from the vaccine?

No, the flu vaccine contains an inactivated virus or proteins that cannot cause infection. It helps your immune system recognize and fight the virus effectively.

How can I protect myself from the flu?

The best way to prevent the flu is to get vaccinated annually. Additionally. practice good hygiene: wash hands frequently, avoid close contact with sick individuals, and maintain a healthy lifestyle.

How often should I get the flu shot?

You should get the flu vaccine every year since flu viruses constantly evolve, and the vaccine is updated annually to protect against new strains.

Is the flu vaccine safe?

Yes, the flu vaccine is extensively tested and recommended by global health organizations like WHO and CDC. Most people experience only mild side effects, if any.

What are the common side effects?

Common side effects include soreness, redness, and swelling at the injection site, as well as low-grade fever, headache, and muscle aches. These side effects are usually mild and go away on their own.

Who needs the flu shot the most?

While everyone above 6 months should get vaccinated, it’s especially crucial for young children, elderly individuals, pregnant women, and those with chronic illnesses.

Can healthy adults skip the flu vaccine?

No, even healthy adults can get the flu and spread it to vulnerable individuals. The vaccine reduces your chances of getting sick and helps protect your community.

Who should NOT take the flu vaccine?

People with severe allergies to any flu shot ingredients or those who had a serious reaction to a previous dose should consult a doctor before getting vaccinated.

Can I take the flu shot if I have a cold?

If you have mild cold symptoms, you can still get vaccinated. However, if you have a fever or feel very unwell, it’s best to wait until you recover.

Can we take other brand flu vaccines?

Yes, you can get the other brand FLU vaccine. WHO’s plays an important role in maintaining uniformity in Influenza Vaccine Strains with all the manufacturers. So, all the flu vaccines contain same strains, you have to choose the latest influenza vaccine available in the marketplace.

Why Annual Flu Vaccination is Important?

Zydus
April 22, 2026

Ever brushed off a scratchy throat or sudden chill thinking, “It’s probably just a cold”? Most of us push through our day and don’t think much about it. But sometimes, that familiar feeling turns out to be flu, AND flu is not something to take LIGHTLY.

It spreads easily and can be serious for people with weaker immunity, which is why the Annual Flu Vaccine plays an important role in prevention. It helps lower the risk of severe illness and complications each year, making it a simple yet important step in staying protected during flu season. 1

Benefits of Flu Vaccine:

Influenza, or the flu, is often brushed off as a routine seasonal illness, but its impact can be serious. In India, flu affects far more people than we realize. Over the last 15 years, more than 1.9 lakh confirmed cases of influenza A (H1N1) have been reported, and over 10,800 deaths have been linked to it.2,3 These numbers reflect how flu can turn into a serious concern.

(Read more about Flu vs. Common cold)

Every flu season brings a different level of risk, and while some people recover in a few days, many others develop complications that can lead to hospitalization. The flu can worsen existing conditions like asthma, heart disease, or diabetes, and in some cases, it can even be life-threatening.

This is where the Annual Flu Vaccine makes a difference. Vaccination helps lower the risk of getting the flu, reduces the chances of severe illness and complications, and decreases the likelihood of hospitalization. Even if someone does get infected after vaccination, the illness is usually milder, and recovery tends to be faster.4 Simply put, the Flu vaccine benefits offer timely protection each season and play a key role in safeguarding overall health, especially for those at higher risk.

Which Age Groups are at Higher Risk of Flu?

While anyone can get the flu, some people are more likely to develop severe illness or complications. These include:

Young children under 5 years, especially those below 2 years of age5

Pregnant women, including up to two weeks after delivery5

Older adults (65 years and above)5

People with chronic respiratory conditions5

Individuals with chronic heart, kidney, liver, or neurological diseases5

People living with diabetes5

Those with blood disorders, including haemoglobinopathies5

Individuals with weakened immunity, such as people with HIV/AIDS, those on long-term corticosteroid therapy, or post-transplant patients5

People with extreme obesity (BMI ≥ 40 kg/m²)5

For people in these higher-risk groups, flu can become serious much faster and because the virus keeps changing every year, Annual Flu Vaccine becomes extremely important for them.

Why is a Single Shot of Flu Vaccine Not Enough?

Flu is caused by the influenza virus, a highly contagious virus that spreads easily through the air and close contact. The types that most commonly affect humans are Influenza A and Influenza B, and these are responsible for the seasonal flu outbreaks we see year after year.4

What makes influenza particularly tricky is its ability to change quietly over time. The virus undergoes small, gradual changes within its genetic structure, a process known as antigenic drift. These changes may seem minor, but they are enough to create new versions of the virus each season.6

Because of antigenic drift, immunity from a previous infection or even last year’s vaccine may not fully protect you this year. 6 That’s why scientists continuously track which flu strains are circulating and update the vaccine to match them as closely as possible.

(Read more about the complete guide to Influenza and Flu Vaccination in India)

In simple terms, the flu keeps changing its disguise. And to stay protected, our prevention strategies need to change with it making the Annual Flu Vaccine a key step in seasonal flu protection.

When is the Right Time to Take Annual Flu Vaccine?

In India, flu activity usually peaks twice a year, between January and March, and again during the post-monsoon period from August to October. Since seasonal patterns can vary across states, getting vaccinated ahead of these peaks is key.7

Best Time for Most People: September and October are ideal months for vaccination. Completing vaccination by the end of October helps ensure protection is in place before flu activity increases.8

Pregnant Females: They can take the flu vaccine at any stage of pregnancy; however, vaccination during the third trimester offers the added benefit of protecting newborns during their first few months of life, when they are too young to be vaccinated themselves.8

Older Adults 65 years and above: They are generally advised not to get vaccinated too early in the year, as protection may decline over time. However, early vaccination can be considered if returning later for vaccination isn’t possible.8

Children less than 5 years: Some children may require two doses of the flu vaccine. In these cases, the first dose should be given as soon as the vaccine is available, followed by a second dose at least four weeks later.8

(Read more about common myth about the Flu Vaccine)

Flu may return every year, but its impact doesn’t have to catch you off guard. With changing virus strains, shifting seasons, and varying levels of risk across age groups, staying protected requires more than just reacting when symptoms appear. The Annual Flu Vaccine remains one of the simplest and most effective ways to reduce the risk of severe illness, complications, and hospitalization, especially for those who are more vulnerable.

Making flu prevention part of your yearly health routine can help protect not just you, but also your family and those around you. Whether you’re caring for young children, expecting a baby, managing a chronic condition, or simply looking to stay healthy through the flu season, timely vaccination plays an important role in overall protection.

Take the next step in safeguarding your health. Talk to your doctor about the Annual Flu Vaccine and India Flu Protection and understand how you can stay protected this flu season.

References:

Key facts about seasonal flu vaccine: https://www.cdc.gov/flu/vaccines/keyfacts.html (Sourced on 22nd Jan 2026)
2010-2017- Seasonal Influenza (H1N1)– State/UT- wise, Year- wise number of cases and deaths: https://ncdc.mohfw.gov.in/wp-content/uploads/2024/02/32804331151679286931.pdf (Sourced on 22nd Jan 2026)
2018-2025-Seasonal Influenza (H1N1)– State/UT- wise, Year- wise number of cases and deaths: https://ncdc.mohfw.gov.in/wp-content/uploads/2025/11/d223cdfb-f708-4eb2-89fd-e7cd91a10fea.pdf (Sourced on 22nd Jan 2026)
https://www.who.int/news-room/fact-sheets/detail/influenza-(seasonal)
https://ncdc.mohfw.gov.in/wp-content/uploads/2024/02/80993440321561442011-1.pdf, Pg. 3- Host factors- High risk. (Sourced on 22nd Jan 2026)
https://ncdc.mohfw.gov.in/wp-content/uploads/2024/02/80993440321561442011-1.pdf, Pg. 2- Genetic Plasticity- Antigenic Drift. (Sourced on 22nd Jan 2026)
https://ncdc.mohfw.gov.in/wp-content/uploads/2024/02/80993440321561442011-1.pdf, Pg. 3,Environmentalfactors, Seasonality. (Sourced on 22nd Jan 2026)
Who needs Flu Vaccine https://www.cdc.gov/flu/vaccines/vaccinations.html