Much is made of nuclear war or a climate emergency as the likely end of humanity, but something much more mundane could threaten mankind: a virus.
Pandemics have been a feature of human history for thousands of years. The black death of the 14th century is thought to have killed up to half of the population of Europe, while the Spanish flu outbreak in 1919 killed more than the first world war that ended shortly before.
In recent years the news agenda concerning outbreaks has been mainly focused on one disease: ebola.
The World Health Organization (WHO) last week declared the crisis a global health emergency.
It is the highest level of alarm the WHO can sound and has only been used four times previously - including the Ebola epidemic that devastated parts of West Africa from 2014 to 2016, and killed more than 11,000 people. More than 1,600 people have died of Ebola in DR Congo since the outbreak began in August 2018.
‘The disease is relentless and devastating,’ said WHO Director-General Dr Tedros Adhanom Ghebreyesus, UN Under-Secretary-General for Humanitarian Affairs and Emergency Relief Coordinator Mark Lowcock, UNICEF Executive Director Henrietta Fore, and World Food Programme Executive Director David Beasley, in a joint statement.
‘Ebola passes from mother to child, husband to wife, patient to caregiver, from the dead body of a victim to the mourning relative. The disease turns the most mundane aspects of everyday life upside down — hurting local businesses, preventing children from going to school and hampering vital and routine health services. It is primarily a health crisis, but one that also critically impacts how people care for their family, view their neighbours and interact with their community.’
Globally, the threat of pandemic such as Ebola remains an ever present threat, but environmental conditions in the UK do not support the natural reservoirs or vectors of any of the haemorrhagic fever viruses, and all recorded cases of VHF in the UK have been acquired abroad, with the exception of one laboratory worker who sustained a needle-stick injury. In the UK however, a much more mundane virus is expected to be the next cause of a pandemic: influenza.
Flu outbreaks occur annually but in the last 100 years, there have been four pandemics, including the particularly deadly Spanish Influenza outbreak which hit in 1918, killing up to 100 million people worldwide. Nearly a century later, a catastrophic flu pandemic still tops the UK Government’s Risk Register of threats to this country.
According to modelling by PHE: many millions of people around the world will become infected; up to around 50% become ill with symptoms; and a variable proportion die from the disease itself or from complications such as pneumonia.
In the UK, up to one half of the population may become infected and between 20,000 and 750,000 additional deaths (that is deaths that would not have happened over the same period of time had a pandemic not taken place) may have occurred by the end of a pandemic in the UK.
‘The prospect of a flu pandemic is one of the highest risks faced by the UK,’ said Duncan Selbie, chief executive of PHE. ‘Ensuring the country is fully prepared and able to respond quickly and effectively is a top priority for PHE and, of course, for the government. The 2009 H1N1 pandemic certainly tested our plans for dealing with a new pandemic strain. Fortunately it was a mild one, but we need to be confident that our planning and responses are sufficiently flexible to deal with every eventuality.’
Past pandemics have varied in scale, severity and consequence, although in general their impact has been much greater than that of even the most severe winter ‘epidemic’.(the difference between an epidemic and a pandemic is: Epidemic is a term that is often broadly used to describe any problem that has grown out of control. Medically speaking, an epidemic is defined as ‘a widespread occurrence of a disease in a community at a particular time.’
Key to this definition is the word ‘occurrence.’ An epidemic is an event in which a disease is actively spreading. In contrast, the term pandemic relates to geographic spread and is used to describe a disease that affects a whole country or the entire world.
Each pandemic is different and, until the virus starts circulating, it is impossible to predict its full effects.
‘The threat of pandemic influenza is ever-present,’ said Dr Tedros Adhanom Ghebreyesus, Director-General, World Health Organization. ‘The on-going risk of a new influenza virus transmitting from animals to humans and potentially causing a pandemic is real. The question is not if we will have another pandemic, but when. We must be vigilant and prepared – the cost of a major influenza outbreak will far outweigh the price of prevention.’
According to PHE, key to the Government’s response plan are mathematical models which simulate how a highly contagious disease may spread. These models help to decide how best to direct NHS resources, like vaccines, antivirals and protective clothing - but the models are only as good as the data that goes into them.
The most recent pandemic occurred in 2009 and was caused by an influenza A (H1N1) virus. It is estimated to have caused between 100,000 and 400,000 deaths globally in the first year alone. The virus was first identified in Mexico in April 2009. It became known as swine flu because it’s similar to flu viruses that affect pigs.
It spread rapidly from country to country because it was a new type of flu virus that few young people were immune to. In the UK, the outbreak wasn’t as serious as originally predicted, largely because many older people were already immune to it. Most cases in the UK were relatively mild – although serious cases still occurred.
The relatively small number of cases resulting in serious illness and death were mostly in younger adults and children – particularly those with underlying health problems – and pregnant women. However, the general mild nature of the 2009/10 pandemic must not be taken as an indicator of the potential severity of future such events, cautions NHS England.
According to PHE, UK health and social care services will be at the forefront of the response to an influenza pandemic coming under, at times, extraordinary strain.
PHE has prepared a detailed plan to respond to potential pandemic. According to the strategy, a sustainable community-based response - with effective arrangements for providing initial assessment, access to antiviral medicines (and vaccines, when available), treatment of complications, home care and access to hospital care is vital as a response to a pandemic. Additionally, an integrated approach to planning and response that effectively employs all of the health and social care services in a local area, using flexible working across all agencies and making best use of potentially scarce facilities and resources, including the skills of volunteers.
Primary care nurses are highlighted as having a critical role in the outbreak of a pandemic. As outlined in the PHE strategy, primary care providers will be responsible for a large deal of vaccination and management of patients during an outbreak. According to NHS England’s flu pandemic preparedness strategy, health services should prepare for up to 30% of symptomatic patients requiring assessment and treatment in usual pathways of primary care, while 1-4% of symptomatic patients will require hospital care, depending on how severe the illness caused by the virus is. There is likely to be increased demand for intensive care.
According to PHE, diseases such as ebola and influenza are of particular public health importance because they can spread within a hospital setting; they have a high case-fatality rate; they are difficult to recognise and detect rapidly; and there is no effective treatment.
While the threat from influenza remains high, the UK has plans in place to manage a pandemic in the future. These incidents are unpredictable, but professionals stress the lessons of previous outbreaks have been learned. As ever, the most important clinical tool is vigilance.