Last Updated: 1 May 2023


There are two main types of influenza viruses: types A and B. Influenza A viruses are found in many different animals, while Influenza B viruses circulate widely only among humans. While it is unusual for people to get influenza infections directly from animals, sporadic human infections and outbreaks caused by certain avian influenza, A viruses have been reported. The influenza A and B viruses are responsible for yearly seasonal flu epidemics. Influenza type A viruses are of the most significance to public health due to their potential to cause an influenza pandemic.

Avian influenza: or bird flu, refers to the disease caused by infection with avian (bird) influenza Type A viruses. These viruses naturally spread among wild birds and can infect domestic poultry and other bird and animal. Bird flu viruses do not normally infect humans; however, sporadic cases have been reported in humans. The disease is typically mild or subclinical for human infections with avian influenza A viruses.

Watch the 27 March 2023 DHMOSH presentation on the current Avian Influenza surveillance.

Swine Influenza: Human infections are primarily acquired through direct contact with infected animals or contaminated environments but do not result in the efficient transmission of these viruses between people.   Most cases have been mild for human infections with swine influenza viruses, with a few cases hospitalized and very few reports of deaths resulting from infection.

Pandemic Influenza : A flu pandemic occurs when a flu virus not previously circulating among humans and to which most people do not have immunity emerges and transmits among humans. These viruses may emerge, circulate and cause large outbreaks outside of the normal influenza season. As most of the population has no immunity to these viruses, the proportion of persons getting infected may be quite large. Some pandemics may result in large numbers of severe infections (e.g., 1918 Spanish Flu), while others will result in large numbers of milder infections (e.g., 2009 H1N1 Pandemic Flu).

In order to reduce the risk of UN personnel and their dependents from contracting influenza, the United Nations Medical Directors (UNMD) have developed specific recommendations for UN personnel. Please consult the UNMD Influenza Risk Mitigation Plan (English / French) and be sure to implement UNMD’s recommendations for the risk category that you fall under. These recommendations will be updated as new information and guidance become available.

The UN Medical Directors Influenza Pandemic Guidelines can assist those responsible for public health and medical preparedness in UN offices to respond to threats and occurrences of pandemic influenza.

 To learn more about current Influenza activity in your region, please visit WHO Influenza Update.

Seasonal Flu

Influenza (or flu) is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and lungs and causes fever, cough and or sore throat.  In temperate climates, it is most common during the fall and winter months.

The flu is actually a different disease from the common cold. The average adult will get a common cold 2 to 4 times a year, whereas the flu is less common, presents differently, and can be life-threatening.  In fact, the WHO estimates that 250,000 to 500,000 deaths worldwide are attributable to flu per year, whilst deaths from the common cold is close to zero. 

The flu spreads from person to person through sneezing, coughing, or touching contaminated surfaces.  Symptoms include fever or feeling feverish/chills, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches and fatigue (tiredness). This differs from the common cold, where symptoms include runny or stuffy nose, which generally is milder than the symptoms of the flu.

Seasonal flu viruses can cause mild to severe illness and even death, particularly in some high-risk individuals.  Persons at increased risk for severe disease include pregnant women, the very young and very old, immune-compromised people, and people with chronic underlying medical conditions.  Seasonal flu viruses evolve continuously, which means that one can get infected multiple times throughout their life. Therefore, it is important to get the seasonal flu shot yearly since the components of seasonal flu vaccines are always updated to ensure its continued effectiveness.

The WHO also released the latest Guidelines for the clinical management of severe illness from influenza virus infections.

Here are the best ways to protect yourself from the flu:

  1. Get a flu vaccine.
  • Flu viruses are constantly changing, and flu vaccines are updated each season -- you should get a flu vaccination every year to get protected.  Everyone ages six months and older are recommended to get a flu vaccine.  A common misconception is that a flu shot causes flu illness – that is not true, the flu vaccine does not cause flu! 
  • The best way to reduce the risk of flu and its potentially serious complications is by getting vaccinated each year.
  1. Take action to stop the spread of germs.
  • Try to avoid close contact with sick people, and if you are sick, stay home to rest and not come to work at least 24 hours after your fever is gone.
  • When sick, cover your nose and mouth with a tissue when you cough or sneeze, and wash your hands often with soap and water. If soap and water are not available, use an alcohol-based hand rub.
  1. Take flu antiviral drugs if your doctor prescribes them.
  • Antibiotics are not effective against the flu.  However, if you get the flu, prescription medicine called antiviral drugs can be used to treat flu illness.  Antiviral drugs can make illness milder and shorten illness time. They may also prevent serious flu complications, so be sure to take the antiviral drugs if your doctor prescribes them to you.

This page will be updated as new information and guidance become available.

Please email if you have any questions related to this page.