13 August 2010

Influenza (H1N1)2009 – post pandemic phase

On 10 August 2010, the World Health Organization (WHO) declared that pandemic (H1N1) 2009 influenza had entered the post pandemic phase [1].

This decision was made following an epidemiological review by the Emergency Committee that determined that influenza (H1N1) 2009 activity worldwide is transitioning to seasonal patterns of transmission. In most countries of both the northern and southern hemispheres, out of season outbreaks are no longer being reported. Nevertheless, it is expected that the H1N1 virus will continue to circulate for some years to come, and that young children, pregnant women, and those with underlying respiratory or other chronic medical conditions will remain at higher risk of severe disease [2].

WHO continues to recommend:

  • monitoring of unusual respiratory events, such as severe illness or death;
  • investigation of severe or unusual cases, clusters or outbreaks of influenza;
  • routine surveillance for influenza-like illness;
  • notification to WHO about sustained transmission of anti-viral resistant influenza (H1N1) 2009 virus, and new types of influenza virus

Advice for travellers

Although the world is now in the post pandemic phase, travellers are still advised to take precautions to reduce their exposure to influenza virus. These include:

Avoiding close contact with symptomatic individuals.

  • Practising ‘cough hygiene’: sneezing or coughing into a tissue and promptly discarding it safely, and frequent hand washing.
  • Avoiding travel if unwell with influenza-like symptoms.

Travellers to the southern hemisphere during the influenza season (April to September) can be offered the monovalent influenza (H1N1) 2009 vaccine [3].

Travellers in clinical risk groups should receive the 2010/11 seasonal influenza vaccine when it becomes available. The seasonal influenza vaccine will include pandemic (H1N1) 2009 virus [4].


1. World Health Organization. H1N1 in post-pandemic phase. 10 August 2010. [Accessed 12 August 2010]. Available at:


2. World Health Organization. What is post-pandemic? 10 August 2010. [Accessed 12 August 2010]. Available at:


3. Department of Health. Pandemic H1N1 (2009) swine flu vaccines for travel use. 18 March 2010. Letter to General Practitioners on travel vaccine. [Accessed 18 March 2010]. Available at


4. Department of Health COM amended letter. The influenza immunisation programme 2010/11. 23 June 2010. [Accessed 12 August 2010]. Available at:



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