Sir Liam Donaldson, the Chief Medical Officer for England, hit the swine flu panic button last week, warning the outbreak is confronting the NHS with its "biggest challenge in a generation". But that didn't mean everyone caught up in the hysteria that has even seen stoical commuters accessorise their work outfits with face masks was panicking.

For dozens of companies, including giant multinational corporations and tiny internet quacks, the outbreak of swine flu frenzy has turned into a licence to print money. And plenty of it. The disease's explosive global advance has sent everyone from private citizens to national governments on a mass shopping spree to try to buy cures: catching swine flu might be not funny but anyone working for what increasingly looks like Swine Flu Inc is laughing all the way to the bank.

Not least GlaxoSmithKline, the British drugs company producing most of the country's swine flu vaccine. As it moved to become the pharmaceutical group with the broadest range of products to tackle the pandemic, last week unveiling plans to sell masks and diagnostic kits to test for the disease as well as vaccines and antiviral medicines, industry analysts estimated GSK could make up to £1bn from sales of its swine flu vaccine alone. It already has orders for 195 million doses, which may cost £6 a dose in the UK, from 16 governments around the world.

Not that that's any cause for apology, apparently. Andrew Witty, GSK's chief executive, refused to be forced on to the defensive about the company's windfall, despite accusations he was trying to turn the crisis into cash. "We are trying to strike a balance between society and our shareholders, who want to see a return on the risks we take," he said. GSK's investors have already seen a return on sales of Relenza, its antiviral drug: second-quarter results showed quarterly sales had increased twentyfold year-on-year to £60m, with first-half sales hitting £230m.

With up to one in three of the population estimated to be at risk of falling ill – and up to 65,000 of those actually dying – the Government has been left with little choice but to dig deep to try to limit the fallout. The story is being repeated around the world, with the United States last week coughing up a further $1bn (£600m) to buy more vaccines, and France ordering an extra 28 million vaccines from Sanofi-Aventis.

And don't think it is just the Government that is brandishing its chequebook to deal with the pandemic that has turned the UK into a global leper. (Britain has been hit harder by swine flu than any other European country.) Judging from the stripped shelves at pharmacies across the country, pretty much everybody is stocking up on anything flu-related. There have been runs on paper surgical masks, thermometers, cold and flu capsules, anti-bacterial hand sanitisers and even tissues. A checkout assistant at Boots in Kensington High Street yesterday said the store was all out of thermometers. "There's no point ordering any more because the warehouses are empty. The same goes for hand gels. And we're doing a roaring trade in surgical masks," she added.

Superdrug has seen sales of its digital thermometers, at £7.82 each, increase tenfold, while Lloyds Chemist said it is seeing a 700 per cent increase in demand for its thermometers and a 70 per cent jump in sales of its £2 antibacterial hand gel. Manufacturers such as Brannan Thermometers have warned they may run short.

It isn't only chemists that are sitting pretty as the numbers of sufferers soar. Even clothing retailers are muscling in on the swine flu sales boom: a newly replenished tower of tissue boxes promising "antiviral" properties teetered between shoppers waiting to pay for their cardigans at one London Marks & Spencer store yesterday. An M&S employee said the tissue mountain had appeared earlier this week, around the same time that the Government announced the number of confirmed swine flu cases had doubled in the past seven days to 100,000, and that the boxes were "selling well". Never mind that a few sheets of toilet roll would probably do the trick.

Meanwhile, although the NHS had just made the flu-treatment drug Tamiflu widely available with the launch of its National Pandemic Flu Service, panicking Brits were still shelling out on their own personal just-in-case supplies. Online vendors, such as the Online Clinic, are making a killing, despite Tamiflu's £119.99 price tag. Its sales representative, Robert Mackay, said: "It depends on the news that day; if it's about deaths then sales are up." Indeed, demand for Tamiflu on the internet has been so high that it has displaced Viagra as the most spammed drug on the web. Other goodies from opportunistic hawkers include the £63.99 "essential" swine flu kit, which includes overalls, booties and alcohol foam; medichecks.com's £125 blood test; and even the £22 "swine flu survival guide" written by someone claiming to be a former US navy sailor.

Swine flu Inc's net doesn't stop there. Even restaurant chains are enjoying a fillip from the pandemic. Home delivery chains in Mexico saw their sales boom as everyone hid indoors amid a nationwide restaurant shutdown. Closer to home, Domino's Pizza said its sales were likely to rise yet further if more people opted to order in rather than go out to eat.

With the number of confirmed cases still just nudging the tip of the predicted iceberg, perhaps we should be thankful that at least one section of the economy is firmly in the black, recession or no recession.

Statistics: How many people will it kill?

As the diagnosis of swine flu is now being carried out over the phone and against a checklist of symptoms, health officials do not have an exact figure of the number of people who been hit by the H1N1 virus in the UK. It is therefore hard to work out what proportion of people infected with the virus are suffering the most severe reactions. Officials are working on the prediction that one in three of us could have been infected at some stage by the end of the year.

So far in the UK, there have been 30 deaths related to swine flu. Health officials are working on the basis that the virus could kill somewhere between 0.1 to 0.35 per cent of all the people it infects. It is this guide which led chief medical officer Sir Liam Donaldson to tell the NHS to prepare for up to 65,000 swine flu deaths in a worst-case scenario, although lower projections were also released.

In comparison, rough averages show that in Britain:

2-3 people die from lightning strikes each year

4 from an allergic reaction to wasp and bee stings

200 from food poisoning

3,000 in road accidents

6,000-10,000 from seasonal flu – although seasons vary in severity

155,000 from cancer

245,000 from heart disease and strokes.