Every day more and more people are being struck by swine flu - even Harry Potter star Rupert Grint hit the headlines after catching it. Yet he and, indeed, most sufferers experienced relatively mild symptoms.
The unpredictability of the virus raises many questions, such as whether it is better to catch swine flu now before it mutates into something more serious. Here NIC FLEMING outlines the latest information that you - and your family - need to know...
Recovery: Swine-flu victim Rupert Grint, left, with Harry Potter co-stars Emma Watson and Daniel Radcliffe
Remind me, what is swine flu?The virus behind the disease is a form of influenza virus sub-type H1N1. The H1N1 strain has previously been a regular cause of flu in humans, but the form causing the current pandemic is new and more dangerous because it contains genetic material from strains that affect birds and pigs, so we have little resistance to it.
How is it diagnosed?Instead of waiting for a swab-test result, swine flu is now being diagnosed based on an assessment of symptoms alone. Do not go to your GP surgery if you suspect you have it - call instead.
How many people have it?As of July 9, the last date for which figures were available, there had been 15,007 cases of H1N1 in the UK, according to the Department of Health. The previous figure of 7,447 was based on laboratory-confirmed cases. In the past week, 27,000 cases were reported by doctors of patients with flu-like symptoms. Some 28 per cent are suspected to be swine flu. The number of new cases is approximately doubling every week. Worldwide, 94,512 cases had been reported to the World Health Organisation by July 6.
What are the symptoms and how does it spread?They are similar to those of ordinary flu but potentially more severe. Likely symptoms are a sudden fever and cough. Other possible signs include headache, tiredness, chills, aching muscles, limb or joint pain, diarrhoea or stomach upset, sore throat, runny nose, sneezing and appetite loss. As with other flu viruses, people become infected when they inhale airborne particles from coughs and sneezes, or touch contaminated hard surfaces and then their nose or mouth.
When am I infectious?As soon as symptoms develop, and for up to five days after in adults and seven days in children. Once the symptoms have gone you are no longer considered infectious.
How long does the virus live for on a surface?It can live on a hard surface for up to 24 hours and a soft one for 20 minutes.
Can I catch swine flu again in winter?Yes. The virus can change and even if your immune system has fought off one strain, it will not recognise a different one.
How dangerous is it?So far, 15 UK deaths have been reported. Currently, 335 individuals in England are hospitalised with swine flu. Of these 43 are in critical care. However, the majority of cases have been mild.
'Until this week, those who had died were pretty sick anyway,' says Professor Robert Dingwall, director of the Institute for Science and Society at the University of Nottingham. 'If you suffer from asthma, high blood pressure or diabetes you may get worse symptoms, but it is only those under active medical treatment that need to be careful.
'Most people will get it without really noticing, or will stay at home for a few days, take paracetamol and be fit to go back to work in a week.'
Who is most vulnerable?The swine flu deaths in the UK have been in those with other very serious underlying medical conditions. More at risk from complications include those with chronic lung, heart, kidney or neurological disease, suppressed immune systems caused by disease or treatment, diabetics, pregnant women, asthmatics, children under the age of five and those aged 65 and over.
could mutate into a more harmful form, as happened in the 1918 Spanish
flu pandemic, also involving the H1N1 strain, when 50 to 100 million
people died worldwide.
So why all the fuss?
However, in this case the second more deadly wave has been attributed to the special circumstances of the First World War, with infected soldiers remaining in the trenches and sick civilians packed into crowded trains and field hospitals.
Is attending a 'swine flu party' to mix with infected friends to pick up immunity against a possible future, more dangerous form, a good idea?Most experts say not. Although the evidence suggests it is relatively mild in most people, this does not tell us how it will affect any specific individual. Deliberately catching the virus would put relatives or friends with other health problems in danger. Prof Dingwall says: 'This is something-that will spread around everybody-but there is no great advantage in getting it sooner rather than later. The risk of a more serious mutation is somewhat theoretical.'
What treatments are available?The drugs Tamiflu and Relenza reduce the amount of virus produced in the body, lessen symptoms and cut the likelihood of it spreading.
They work best if taken before infection and must be taken within about 48 hours of the appearance of symptoms to be effective. The UK has stockpiled enough to treat half of the population and has ordered enough for 80 per cent.