The swine flu pandemic of 2009 was one of the worst flu scares in recent memory, even if its actual effects ended up being relatively moderate. Now something unambiguously good could come of all this: a universal flu vaccine.
As many as sixty million people were infected with the H1N1 virus, although only about 18,000 people are known to have died from the disease. What researchers are now discovering is what swine flu leaves behind: a superpowered immune system with antibodies that can kill off any new flu virus, not just a return of H1N1.
Recent research on nine swine flu survivors revealed that the infection had caused all their immune systems to go into overdrive, creating a huge range of flu antibodies that aren't needed to fight off swine flu but would be very useful if any number of other flu strains tried to invade the subjects' bodies. More common flu strains like the seasonal flu or the very mild flu virus used to create the flu vaccine don't activate this many antibodies, suggesting there's something unusual about H1N1 that triggers this powerful immune response.
The power of the H1N1 immune response is extraordinary. According to the researchers, five of the types of antibodies isolated in their research would be enough to fight off all seasonal flu variations, the Spanish flu virus that killed as many as 50 million people in the pandemic of 1918, and a potentially deadly bird flu strain known as H5N1.
The researchers say the uniqueness of the swine flu is what triggered this response. The immune system didn't immediately know what to do with the virus, so it started creating lots of different antibodies based on its memory of other flu viruses it had previously encountered. By the time the immune system found the right antibodies to fight off the swine flu, enough had been created to ward off all other influenza variants as well. We don't know yet whether the H1N1 vaccine also transferred these super immunity properties, although that's next on the researchers' to-do list.
Oxford University virus expert Dr. Sarah Gilbert, this could well lead us to a universal flu vaccine, and in the relatively near future, too:
"Many scientists are working to develop a vaccine that would protect against the many strains of flu virus. This work gives us more confidence that it will be possible to generate a universal flu vaccine. It will take at least five years before anything like this could be widely available."
Five years is a long time to wait, but considering that as many as 500,000 people die every year from various flu strains, it seems like a universal vaccine is very much worth waiting for.
In the nine patients they studied who had caught swine flu during the pandemic, they found the infection had triggered the production of a wide range of antibodies that are only very rarely seen after seasonal flu infections or flu vaccination.
Five antibodies isolated by the team could fight all the seasonal H1N1 flu strains from the last decade, the devastating "Spanish flu" strain from 1918 which killed up to 50m people, plus a potentially deadly bird flu H5N1 strain.
The researchers believe the "extraordinarily" powerful antibodies were created as the body learned how to fight the new infection with swine flu using its old memory of how to fight off other flu viruses.
Next they plan to examine the immune response of people who were vaccinated against last year's swine flu but did not get sick to see if they too have the same super immunity to flu.
Dr Sarah Gilbert is a expert in viruses at Oxford University and has been testing her own prototype universal flu vaccine.
She said: "Many scientists are working to develop a vaccine that would protect against the many strains of flu virus.
"This work gives us more confidence that it will be possible to generate a universal flu vaccine."
But she said it would take many years for a product to go through the necessary tests and trials.
"It will take at least five years before anything like this could be widely available."
The number of deaths this winter from flu verified by the Health Protection Agency currently is 50, with 45 of these due to swine flu.