Pandemic influenza: what it is and how the UK plans for it

UK Government guidance explains that there are important differences between ordinary seasonal flu and pandemic flu. Pandemic influenza emerges as a result of a new flu virus that is markedly different from recently circulating strains. Because few, if any, people have immunity to the new virus, it can spread easily and cause more serious illness than seasonal flu.

The guidance describes pandemics as a natural phenomenon that has occurred from time to time for centuries, including three times during the 20th century. It says that some features of modern society, such as air travel, could accelerate the rate of spread, and that the 2009 H1N1 pandemic should not be seen as representative of future pandemics.

The World Health Organization Global Influenza Surveillance Network, which the guidance describes as comprising 105 countries, monitors circulating influenza viruses to detect the emergence of those with pandemic potential.

The UK guidance states that each pandemic is different and that, until the virus starts circulating, it is impossible to predict its full effects. Based on historical information and scientific evidence, it gives planning assumptions: that 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.

For the UK, the guidance says up to one half of the population may become infected and that between 20,000 and 750,000 additional deaths may occur by the end of a pandemic. These are planning assumptions from the UK influenza pandemic preparedness strategy and are not forecasts. The guidance adds that, without early or effective interventions, society is likely to face social and economic disruption, threats to essential services and large numbers of staff absent from work at any one time.

The NHS describes flu symptoms as coming on very quickly and including a sudden high temperature, an aching body, feeling tired or exhausted, a dry cough, a sore throat, a headache, difficulty sleeping and loss of appetite. In children the symptoms are similar, but they can also get ear pain, sore eyes and swollen glands and appear less active.

The NHS notes that cold and flu symptoms are similar, but flu tends to be more severe, appears within a few hours, affects more than the nose and throat, and makes you feel exhausted and too unwell to carry on as normal. These are the symptoms of seasonal flu; the sources read do not describe a different symptom pattern for a future pandemic strain.

The NHS says to ask for an urgent GP appointment or get help from NHS 111 if you or your child have symptoms of flu and you are worried about a baby’s or child’s symptoms, are 65 or over, are pregnant or have recently given birth, have a long-term medical condition such as diabetes or a condition affecting the heart, lungs, liver, kidneys, brain or nerves, have a weakened immune system, feel very unwell, feel short of breath, or your symptoms do not improve after 7 days.

It says to call 999 or go to A&E if you get sudden chest pain, have severe difficulty breathing (gasping, choking or not able to get words out), or start coughing up blood. Do not drive yourself to A&E; ask someone to drive you or call 999.

The NHS suggests that if you have flu you rest and sleep, take paracetamol or ibuprofen to lower your temperature and ease aches and pains, and drink plenty of water to avoid dehydration. Do not give aspirin to children under 16. Antibiotics do not work for viral infections such as flu and GPs do not recommend them.

Flu is very infectious. The NHS says you are more likely to give it to others in the first 5 days after getting infected, and that it spreads through germs from coughs and sneezes that can live on hands and surfaces for 24 hours. To reduce spread it advises washing hands often with warm water and soap, covering your mouth and nose with a tissue when you cough or sneeze, binning used tissues quickly, and staying at home and avoiding contact if you have a high temperature or do not feel well enough to do normal activities.

The NHS says the flu vaccine helps protect against flu and is offered every year in autumn or early winter to some adults and children at higher risk of getting seriously ill. This describes the seasonal programme; the sources read do not describe a vaccine for a future pandemic strain, which would depend on the virus that emerges.

UK Government guidance sets out planning at national, local and sector level, with the Department of Health as the lead department and the guidance emphasising that plans are unlikely to be successful without the active support of individuals and communities. It also highlights the importance of the public following government advice and adopting basic hygiene measures.

In the UK, the response to a pandemic would be led through NHS and government structures, with health and social care services at the forefront of the response, as the guidance describes. The NHS says the seasonal flu vaccine is offered every year to some adults and children at higher risk.

Private care would not change the public health measures that apply. For individuals, the practical steps are the same as for any flu: check whether you are eligible for NHS vaccination, know when to seek urgent help, and follow public health advice if a pandemic is declared.