Reports of illness caused by the novel virus, influenza A/H1N1v, known as swine flu, first emerged in Mexico in April. On 11 June, the World Health Organisation (WHO) raised the worldwide pandemic alert to Phase 6, indicating that a global pandemic is underway. This reflects the fact there are now ongoing community level outbreaks, with person to person spread, in multiple countries. On 15 June, 76 countries had reported 35,928 cases and this may be a considerable underestimate. (1) The highest number of cases has been reported in the USA, followed by Mexico, Canada, Australia and Chile.
Globally, 163 deaths have been attributed to the illness.
At the time of writing, over 2,500 cases have been reported in the UK, with the West Midlands, Scotland and London being particularly badly affected. Much remains to be unravelled about the virus and its epidemiology, but the highest number of cases has been among males aged 10-19. 39 people have been admitted to hospital, while one patient in Scotland is believed to have died as a consequence.
The UK was thought to be one of the countries best prepared to cope with a pandemic, although the source was not avian influenza from South East Asia, as many had been anticipating. The Health Protection Agency (HPA) in England, and equivalent bodies in Scotland, Wales and Northern Ireland, have taken a proactive approach to containing the virus. To date over 60 schools have been closed at some point due to confirmation of one or more cases in pupils or staff members.
There is much we still don't know about the behaviour of the virus, but there are concerns that countries in the northern hemisphere will see a second, potentially more devastating 'wave' of influenza activity during the normal autumnal flu season this year, as occurred during previous global pandemics. Even if symptoms remain mild, a flu-like illness affecting a large proportion of the working population could have a detrimental economic impact in already troubled times. The consequences for healthcare delivery, of both staff illness and a potential sudden surge of patients, also warrant consideration.
Looking beyond our borders, the rapid inter-continental spread reflects globalisation and a culture of easy international travel. But the global spread of swine flu further highlights the yawning gap between rich and poor.(2) While Western countries invest considerable amounts in containment and mitigation policies, many developing countries will struggle to implement any such strategies in the face of limited healthcare resources.
Unless otherwise stated all figures were taken from the websites of the Health Protection Agency and US Centers for Disease Control and Prevention. Accessed 21 June.