Influenza World Health Care Professionals

According to the World Health Organization (WHO), an influenza pandemic will occur when a new strain of influenza A virus emerges, to which the human population has little or no immunity, resulting in several, simultaneous epidemics worldwide with enormous numbers of deaths and illness. [1]
There are three prerequisites for an influenza pandemic:

• emergence of a novel influenza A virus subtype that can infect humans
• ability of the new influenza strain to replicate in humans and cause serious illness
• efficient transmission of the new influenza strain among humans.

Phase of pandemic alert

Six distinct phases have been defined by the WHO to facilitate pandemic preparedness planning (see figure below). [2] As of April 2007, the world is at phase 3 of a pandemic alert period. [3] This means that human infections with a new influenza virus subtype have been identified (avian influenza strain, H5N1); though, human-to-human transmission of the virus is rare. If the virus mutates and acquires the ability to spread rapidly among humans, a pandemic may occur.
To check the latest WHO phase of pandemic alert visit: http://www.who.int/csr/disease/avian_influenza/phase/en/ index.html

        

Who is at risk from pandemic influenza?

Historical evidence from the Spanish influenza pandemic of 1918 indicates that in contrast to seasonal influenza, which mainly affects young children and those older than 65 years, pandemic influenza is most likely to cause deaths of healthy individuals between the ages of 20 and 45 years. [2] Overall, 99% of deaths from the 1918 pandemic occurred in people younger than 65 years. [4]

Impact of a pandemic

In the event of a pandemic, there is likely to be:

• widespread illness and death
• health services overload
• economic disruption
• social disruption

Widespread illness and death
A relatively conservative estimate has predicted that within a very short time-frame there could be up to:

• 233 million outpatient visits
• 5.2 million hospital admissions
• 7.4 million deaths. [1]

However, the severity of the pandemic and the number of deaths will depend on
the:

• number of people infected
• virulence of the virus
• demographics and vulnerability of affected populations
• availability and effectiveness of preventative measures.

Even in the best-case scenario, experts predict that 2–7 million people could die in the next influenza pandemic. However, if the pandemic virus is especially virulent this number could be dramatically higher. [5]

Health services overload
A substantial proportion of the world’s population will require some form of medical care during an influenza pandemic. [6] The WHO predicts that healthcare systems will become overwhelmed, creating a strain on hospital staff, and a shortage of beds, ventilators, and other supplies. [6]

Economic disruption
High rates of illness and workplace absenteeism are expected during an influenza pandemic, resulting in a dramatic impact on all kinds of businesses.[6]

Furthermore, as people avoid social contact in public places, such as shopping centres, restaurants, sporting events, and cinemas etc., there will be a significant reduction in demand for products and services creating a huge impact on businesses and the economy.

Social disruption
The lack of manpower during an influenza pandemic will have a substantial impact on society, with potential breakdowns in community services, such as healthcare, public transport, policing, power and communications.

International travel would decline as people try to avoid influenza ‘hotspots’ and governments place restrictions on travel. People may also quarantine themselves and their family at home and avoid places where social contact is likely (e.g. schools, public transport, places of worship, libraries etc.).

1. World Health Organization. WHO checklist for influenza preparedness planning. Available here.
2. World Health Organization. WHO global influenza preparedness plan. Available here.
3. World Health Organization. Current WHO phase of pandemic alert. Available here.
4. Kamps BS, Hoffmann C, Preiser W, eds. Influenza report. Available here.
5. World Health Organization. Estimating the impact of the next influenza pandemic: enhancing preparedness. Available here.
6. World Health Organization. Ten things you need to know about pandemic influenza. Available here.