How Long Does Influenza Last?


The flu season in the different parts of the world brings a lot of disruption and misery. Millions of affected people experience influenza (flu) symptoms which are sometimes very uncomfortable. Inevitably, they ask themselves, “how long does influenza last?”

This article will address that issue of how long flu last. But there will be a brief discussion of other issues surrounding influenza, to enable the Reader to have a deeper understanding of the disease.

Specifically, this article will explore:

  • what causes influenza
  • how long does flu last?
  • influenza treatment
  • how long does influenza season last?
  • influenza prevention


Flu is a respiratory illness. It is an infectious disease affecting the Respiratory Tract. Influenza is very contagious.

Is flu caused by a virus? Can flu be treated with antibiotics?

The disease is caused by a virus that exists in three types. The virus is influenza virus, types A, B and C.

Because viruses are not treated with antibiotics, flu cannot be treated with antibiotics. Antibiotics are effective only against bacteria.

Flu is transmitted by

  • floating in the air in droplets, from an infected person. This happens when they cough, sneeze, talk or sing. The virus can then enter the airways of another person who breathes it in.
  • surviving on surfaces like door knobs, furniture, shared equipment. It gets picked up by an unsuspecting victim who touches the surface. The virus then enters the body of the victim when they touch their nose, eyes or ears with unclean hands
  • kissing (this is similar to the touch mode above, though more direct)


After being infected with flu as described in the first paragraph, symptoms develop after 1 to 4 days. Notably, a victim can be infectious one day before showing symptoms.

Then the flu symptoms worsen fairly rapidly over the next few days. The symptoms reach a peak after about 4-5 days.

Overall, a typical flu usually lasts a total of 5-7 days. During this time, the subject remains highly contagious.

A different pattern has been noted with the H1N1 virus. It tends to run a protracted course of (up to 3) weeks.


The treatment of flu is supportive. The aim is to relieve distressing symptoms and to prevent harm that can be caused by abnormal parameters.

Cough (and congestion) – can be controlled by an antihistamine

Fever – can be managed with paracetamol or a Nonsteroidal Anti-inflammatory Drug (NSAID)

Pain – can be treated with paracetamol or a Nonsteroidal Anti-inflammatory Drug (NSAID)

Congestion and secretions – can be reduced by decongestants

Immunity can be boosted by high-dose Vitamin C

Lethargy – usually improved through the use of caffeine

The above drugs are often used together in combination medicines, tablets or capsules.

Hydration needs to be carefully observed, as water loss results from fever, rapid breathing and poor oral intake due to appetite loss.

H1N1 flu treatment is the one that has a specific antiviral to use. The antiviral, oseltamivir, is sold under the tradename “Tamiflu”.


Due to a variety of reasons, influenza virus is most rampant in Winter. Flu season therefore equates to Winter months.

In the Northern hemisphere, the flu season is approximately from October to May. And in the Southern hemisphere, it is approximately from May through August, to October.


There are several ways to prevent influenza / flu. These centre around good hygiene. More info on this can be found in the article, “Flu Season Prevention Tips” on this website.

There is a frequent question, “how long does flu shot last?”

The influenza (flu) shot is dealt with in detail in the above article. It just needs to be mentioned that the annual flu vaccine is only valid for the year in question. This is because different strains of the flu virus predominate in different years.


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13 Replies to “How Long Does Influenza Last?”

  1. Thank for this elaborate work on flu. I know it is respiratory but never thought of kissing as one of the basic modes of transmission, also I did not know it can survive on surfaces. Now I know that a cleaning of surfaces especially during the flu season will reduce its transmission and keep me safe from sneezing, cough and constant feverish condition 

    1. Hi Parameter,

      Thanks for reading through the article and providing valuable feedback.

      Yes indeed, surfaces play a huge role. There has been a marked reduction in flu cases this year because of the massive disinfection efforts necessitated by the COVID-19 pandemic.


  2. Thanks for this article you have here which covers the topic of Influenza (Flu) in toto. There is a lot of information on influenza in this article, and I am glad to be receiving such information and gaining knowledge from reading this article. I do hope to read more of such educating and informative articles from you.

  3. Thank you so much for sharing with us such a beautiful article on health. Nowadays influenza has spread around which has become a common disease. People should be aware of the fact that the influenza virus infects people through various means. A few days ago I was infected with the influenza virus due to a cold problem which caused my favorite fever. So I took paracetamol as per the doctor’s advice and within a few days I recovered. Also, the doctor asked me to give Flu vaccine in and later I gave it. Which can protect me from this virus for at least a year. Lastly, when infected with the virus, it may be temporary, but to avoid it, you must get vaccinated with health awareness.

    1. Hi,

      Thanks so much for reading through the article and providing valuable input.

      A flu vaccine does help to prevent the annual flu. Health awareness, as you say, is however key.


  4. Hi Dr

    I like your post, you made it very simple and easy to understand.

    I thought that I was contagious only when the flu manifests itself, but now I have learned that I am contagious way before that. Can you give me the signs that show that I have flu before it manifests? That way I may know how to keep myself from contaminating others.


    1. Hi,

      Thanks for the feedback.

      For about 24 hours after acquiring the infection, you could be ABSOLUTELY SYMPTOM-FREE.

      I will provide for you, a link to a thermometer. You could use it to check your temperature as frequently as you wish, and certainly whenever you feel a bit “off”. It might detect an early fever.


  5. Hey Tebogo 

    Thank you for tackling this simple but complicated subject. I find myself confused for as much as I can remember whenever any member of my family goes to the Doctor for flu, they normally give us antibiotics. What do you think heir reasons are?

    i also think taking hygiene serious can reduce flu cases, hence during this pandemic when we were all hygiene conscious  none of my kids had flu this winter.

    1. Hi Bogadi,

      Antibiotic abuse is a worldwide problem. Sometimes Healthcare professionals may feel unsure whether an illness is viral or bacterial, and decide to be “on the safe side” by providing antibiotic cover. Unfortunately, this is in many cases inappropriate.


  6. Hello Dr Teboho Lekhanya,

    This is one very nice piece of information you have shared with us all and flu is very common in different places of the world so it’s not a new name at all. Nevertheless, the lack of knowledge of how long it last and how it can be transmitted is what most of us do not have. I have come to notice that flu is common is a certain part of the country, could there a be factor that causes it?

    1. Hi,

      Thanks for the feedback.

      The part of the country that you have noted to have more flu than others, could be having any of several Public Health challenges:

      – it could be overcrowded, with people living close to each other

      – it could be having a population that is more elderly than other areas

      – the population could also be having more immune compromising conditions like Diabetes

      – the region could furthest from the Equator, or any other reason that could make it COLDER


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