User Tools

    To create and edit articles, please register and log-in

Main Menu : categories & index etc.

Main menu
Click categories to expand

A-Z listingplugin-autotooltip__plain plugin-autotooltip_bigA-Z listing

This is an alphabetical index of all content pages.

Other categories



Also see

Importance Ratings
Curator's rationale
AI Policy

Twitter feed 𝕏

Feeds + s.e.o. etc.
rss / xml feed
sitemap file
A-Z listing (archived)

Indexed under : Medicine / Diseases / G - L

Wikenigma - an Encyclopedia of Unknowns Wikenigma - an Encyclopedia of the Unknown

Influenza seasonality

The incidence of Influenza ('flu) is tightly linked to the seasons. In temperate climates, it's thought that the disease exists at low levels during the warmer Summer months, and then dramatically peaks during the Winter.

The reasons for this 'seasonality' have been examined and discussed at length for more than a century.

There are dozens of different theories, none of which has been accepted as the cause. It's likely that the Winter increase is due to a variety of factors - but there is currently no agreement on which are the important ones, or how they might be interacting.

While epidemiologists, virologists, immunologists, and mathematicians have all developed laudable theoretical and empirical models to explain seasonality, none are so complete as to fully and adequately explain the phenomenon.“
[Source link below]

Theories include the possible influences of :

  • Changes in ventilation (as more people tend to gather inside buildings during the winter)
  • The general health of the population, which tends to be lower in Winter (due to lack of sunlight, poorer diet etc) leading to greater chances of being infected.
  • The ambient temperature which somehow affects the virus replication.
  • The possibility that indoor heating somehow increases the virus potential.
  • Increased air travel aiding the spread of the virus.
  • 'Bulk aerosol transport' (.i.e. movements of large amounts of air containing the virus)
  • Global weather systems - such as El Niño.

For more details see : Influenza Seasonality: Underlying Causes and Modeling Theories Open AccessJournal of Virology, Vol. 81, No. 11, 2020

The myriad theories accounting for seasonality reviewed in this paper, as well as those that will hopefully emerge as influenza continues to rise in prominence, suggest that the elegant and predictable periodicity of nonpandemic influenza is caused by a less-than-straightforward interaction of many different factors.”
[Source link above]


It's likely that many of the poorly understood mechanisms which affect the seasonal incidence of 'flu will also be important factors for the current Covid-19plugin-autotooltip__plain plugin-autotooltip_bigCovid-19

Editor's note : Because of the intense, ongoing, global research efforts related to Covid-19, it's difficult to get an accurate picture of the unknown factors. Here are some of the many as-yet-unanswered questions Why does the virus have much more serious eff…

In addition, in many countries, the latest Winter figures for the number of 'flu cases has recently dramatically fallen [ref. needed]. It's assumed that the drop is related to behavioural changes linked to the Covid epidemic.

    Please share this page to help promote Wikenigma !

Dear reader : Do you have any suggestions for the site's content?

Ideas for new topics, and suggested additions / corrections for older ones, are always welcome.

If you have skills or interests in a particular field, and have suggestions for Wikenigma, get in touch !

Or, if you'd like to become a regular contributor . . . request a login password. Registered users can edit the entire content of the site, and also create new pages.

( The 'Notes for contributors' section in the main menu has further information and guidelines etc.)

Automatic Translation

You are currently viewing an auto-translated version of Wikenigma

Please be aware that no automatic translation engines are 100% accurate, and so the auto-translated content will very probably feature errors and omissions.

Nevertheless, Wikenigma hopes that the translated content will help to attract a wider global audience.

Show another (random) article

Further resources :