The treatment — using a new technique and tested for the first time on humans infected with flu — targets a different part of the flu virus to traditional vaccines, meaning it does not need to be expensively reformulated every year to match the most prevalent virus that is circulating the world.
Developed by a team led by Dr. Sarah Gilbert at Oxford’s Jenner Institute, the vaccine targets proteins inside the flu virus that are common across all strains, instead of those that sit on the virus’s external coat, which are liable to mutate.
If used widely a universal flu vaccine could prevent pandemics, such as the swine flu outbreaks of recent years, and end the need for a seasonal flu jab.
“The problem with flu is that you’ve got lots of different strains and they keep changing,” said Adrian Hill, director of the Jenner Institute. “Occasionally one comes out of wildfowl or pigs and we’re not immune to it. We need new vaccines and we can’t make the vaccines fast enough.” A universal vaccine would save the time and money now needed to create vaccines to fight whatever particular virus has emerged in any year. In the UK, the government spent an estimated GBP1.2bn in preparing for the swine flu outbreak of last winter.
The process of developing a seasonal vaccine takes at least four months and if the flu strain is highly pathogenic — as in 1918 when millions of people died — the delay means more people get sick and die before the vaccine is ready.
This winter the government was criticised for its handling of the annual winter flu outbreak. Shortages of the seasonal flu vaccine became so acute in some areas that GPs were told to use old stocks of swine flu vaccine instead.
“If we were using the same vaccine year in, year out, it would be more like vaccinating against other diseases like tetanus,” said Gilbert. “It would become a routine vaccination that would be manufactured and used all the time at a steady level. We wouldn’t have these sudden demands or shortages — all that would stop.” While traditional vaccines prompt the body to create antibodies, Gilbert’s vaccine boosts the number of the body’s T—cells, another key part of the immune system. These can identify and destroy body cells that have been infected by a virus.
In her trial, Gilbert vaccinated 11 healthy volunteers and then infected them, along with 11 non—vaccinated volunteers, with the Wisconsin strain of the H3N2 influenza A virus, which was first isolated in 2005. She monitored the volunteers’ symptoms twice a day, including runny noses, coughs and sore throats, and she calculated how much mucus everyone produced by weighing tissues they used.
Though a small study, it was significant in that it was the first vaccine of its type to be tested on people.
Gilbert said: “This is the first time anyone’s tested if you can boost somebody’s T—cell response to flu and, having done that, does it help protect against getting flu. It’s the first time anybody’s done that in people.” Her results showed that the vaccine worked as planned. “Fewer of the people who were vaccinated got flu than the people who weren’t vaccinated,” said Gilbert. “We did get an indication that the vaccine was protecting people, not only from the numbers of people who got flu but also from looking at their T—cells before we gave them flu. The people we vaccinated had T—cells that were more activated. The people we hadn’t vaccinated had T—cells as well but they were in a resting state so they would probably have taken longer to do anything. The volunteers we vaccinated had T—cells that were activated, primed and ready to kill.” Gilbert has now sent her results to a scientific journal.
Hill said: “What we’ll probably do is take the existing flu vaccine and mix in the new virus—vector vaccine, so you get both good antibodies and good T—cells. As well as giving you the antibodies for this season’s strain of flu, we’ll give you some T—cells that will cover this season, next year, next year and thereafter. It may not be 100% effective against all strains, but at least if there were a pandemic coming around, it would cover you for any strain.” It is believed that the vaccine could provide better protection against flu for older people. The Jenner Institute scientists are already testing it on people over 50, a group that does not respond so well to traditional vaccines.
The next step for the T—cell vaccine is to stage a field trial in which several thousand people are given the vaccine and their outcomes are compared with several thousand people who do not get the vaccine. It will take several more years, therefore, before Gilbert’s vaccine can be licensed for use alongside traditional, antibody—inducing vaccines.
Mark Fielder, a medical microbiologist at Kingston University, said: “This study represents some potentially very exciting findings with positive implications not only for influenza but possibly for infectious disease in a wider context. However, I think that a larger trial will be able to confirm these findings and let this technology be taken forward.” Copyright: Guardian News & Media 2011
