Influenza v/s COVID – Similarities and Differences

Dear Reader,

As we deal with this pandemic together, we at Medi Assist take this opportunity to share our understanding of Influenza (common cold or the flu) and Covid symptoms, especially when the flu season is upon us. Since both of these show very similar symptoms, we have curated a set of FAQs to help employees,  managers, and organizations understand both better, individually and together.

1. What is Influenza or the flu?

It is a viral infection that attacks your nose, throat, and lungs. Commonly known as the flu, it’s not the same as stomach “flu” viruses that cause diarrhea and vomiting. For most people, the flu resolves on its own. But sometimes, Influenza and its complications can be deadly. People at higher risk of developing flu complications include:

  • Young children under age 5, and especially those under 6 months Adults older than age 65
  • Residents of nursing homes and other long-term care facilities
  • Pregnant women and women up to two weeks after giving birth People with weakened immune systems
  • Native Americans
  • People who have chronic illnesses, such as asthma, heart disease, kidney disease,  liver disease, and diabetes
  • People who are very obese, with a body mass index (BMI) of 40 or higher Though the annual influenza vaccine isn’t 100% effective, it’s still your best defense against the flu.

2. What are the similarities in symptoms between Covid-19 and Influenza?

Both COVID-19 and flu can range from asymptomatic to severe symptoms. Common symptoms that COVID19 and flu share include:

  • Fever or feeling feverish/having chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue (tiredness)
  • Sore throat
  • Runny or stuffy nose
  • Muscle pain or body aches
  • Headache
  • Loss of/change in taste or smell is more frequent with COVID-19.

3. How long after do the symptoms appear on exposure and infection with either of the viruses?


For both COVID-19 and flu, one or more days can pass between before a person becomes infected and when they start to experience illness symptoms.


If a person has COVID-19, it could take them longer to experience symptoms than if they had flu.

4. How long can someone spread either of the viruses?


For both COVID-19 and flu, it’s possible to spread the virus for at least 1 day before experiencing any symptoms.


If a person has COVID-19, they could be contagious for longer than if they had flu.

5. How does either of these viruses spread?


Both COVID-19 and flu can spread from person to person in close contact with one another (within about 6 feet). Both are spread mainly by large and small particles containing viruses expelled when people with the illness (COVID-19 or flu) cough, sneeze or talk.

Although both spread by inhaling the respective virus, it may be possible that a person can get infected by touching (for example, shaking hands with someone who has the virus on their hands) or by touching a surface or object that the virus on it, and then touching their own mouth, nose, or eyes.


While the virus that causes COVID-19 and flu viruses are thought to spread in similar ways, the virus that causes COVID-19 is generally more contagious than flu viruses. Also, COVID-19 spreads more than the flu.

6. Influenza (flu) vaccination:

What is the quadrivalent flu vaccine?

Quadrivalent influenza (flu) vaccine is designed to protect against four different flu viruses, including two influenza A viruses and two influenza B viruses.

Why was the quadrivalent flu vaccine developed?

For many years, flu vaccines were designed to protect against three different flu viruses: an influenza A(H1N1) virus, an influenza A(H3N2) virus, and one influenza B  virus, even though there are two different lineages of B viruses that circulate during most seasons. Adding a B virus from the second lineage was done to give broader protection against circulating flu viruses.

Who can get a quadrivalent flu vaccine?

For the 2021-2022 season, all flu vaccines in India are quadrivalent vaccines. Different vaccines are approved for other age groups. A quadrivalent flu shot can be given to children as young as 6 months old.

Who shouldn’t get a quadrivalent flu vaccine?

Different influenza (flu) vaccines are approved for people in various age groups. In addition, some vaccines are not recommended for certain groups of people. Factors that can determine a person’s suitability for vaccination, or vaccination with a particular vaccine, include a person’s age, health (current and past), and allergies to a flu vaccine or its components. Please check with your doctor for further information.

Are any of the available flu vaccines recommended over the others? For the 2021-2022 flu season, it is recommended that annual Influenza (flu)

vaccination is for everyone 6 months and older with any licensed influenza vaccine appropriate for the recipient’s age and health status with no preference expressed for any one vaccine over another.

There are many vaccine options to choose from, but the most important thing is for all people 6 months and older to get a flu vaccine every year. If you have questions about which vaccine is best for you, talk to your doctor or other healthcare professionals.

Are quadrivalent flu vaccines safe?

Yes. Flu vaccines that protect against four flu viruses have a safety profile similar to seasonal flu vaccines made to protect against three viruses, with mild side effects primarily. Like all seasonal flu vaccines, vaccines that protect against four flu viruses are monitored annually for safety and effectiveness.

Quadrivalent vaccines cannot cause flu because they contain ‘inactivated’ (killed) virus, attenuated (weakened) virus, or are made using recombinant methods that don’t use flu virus in the manufacturing process.

Special Consideration Regarding Egg Allergy

People with egg allergies can receive any licensed, recommended age-appropriate influenza vaccine. People who have a history of severe egg allergy (those who have had any symptom other than hives after exposure to egg) should be vaccinated in a  medical setting, supervised by a health care provider who can recognize and manage severe allergic reactions.


  1. Centers of Disease Control and Prevention (CDC)
  2. World Health Organization (WHO)

Disclaimer – This information has been taken from relevant sources. However, we require you to please check the guidelines from the government and health authorities for regular updates on this variant and take all precautionary measures regularly.

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