WHO declares pandemic, but severity is moderate

04.08.2009

On 11 June 2009, the pandemic (H1N1) 2009 was declared.

An influenza pandemic occurs when a new influenza virus subtype emerges and spreads easily among human beings.

Pandemics have been observed for several hundred years. The best documented pandemics occurred during the 20th century, in 1918 (Spanish flu), 1957 (Asian flu) and 1968 (Hong Kong flu). These varied in severity with an estimated 1-50 million excess deaths during the pandemic.

Pandemic phases

WHO uses a six phased scale of pandemic alert to inform the world of the global spread of a new virus and as a global framework for countries in pandemic preparedness and response planning.

Based on assessment of all available information and following several expert consultations on influenza A(H1N1), on 11 June 2009, Dr Margaret Chan, WHO's Director-General, raised the current level of influenza pandemic alert from phase 5 to 6 and thereby declaring the pandemic (H1N1) 2009.

Pandemic Alert Phase 6 is defined as a new virus causing sustained community level outbreaks in more than one WHO region.

The pandemic phase does not indicate the severity of disease caused by the new virus. The severity of the pandemic is classified as moderated, aggravated or severe. The pandemic (H1N1) 2009 has been classified as a pandemic of moderate severity. WHO will continue to monitor the severity of the pandemic as it may change over time.

A moderate pandemic

Based on the information about the virus to date, as well as its impact on countries' health systems, societies and the economies, WHO considers the overall global severity of the pandemic to be moderate. The situation varies between countries and may change over time. Most of the cases in individuals have been mild, with a limited number of severe cases and deaths. In general, health systems and hospitals have been able to cope with the numbers of people seeking care, but even mild cases and the current level of severe cases could significantly affect health systems and society.

The overwhelming majority of people who catch the virus recover without medical attention. Of concern are the limited number of serious cases and deaths that are occurring primarily among young people, including the previously healthy and those with pre-existing medical conditions or pregnancy.

Advice for the public

At present, the vast majority of people who fall ill can be cared for at home and recover without medical treatment.
People should be aware of signs of severe illness and not delay seeking medical attention in cases where someone experiences shortness of breath or difficulty breathing, or if a fever continues more than three days.
Anyone who becomes ill with a fever above 38°C should seek medical attention.
Parents with a young child who is ill should get medical care if the child has fast or labored breathing, continuing fever or convulsions (seizures), or is confused, unconscious or difficult to awaken.
People caring for someone who is sick should protect themselves and others with careful hygiene (hand washing, cough etiquette).
People should become informed, and stay informed as things change.

Source: World Health Organization (WHO) www.euro.who.int

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