A new kind of flu vaccine that works against many different strains of influenza virus has proved to be more effective than conventional vaccines at stimulating the immune defences of laboratory ferrets, the standard animal “model” of the human infection, a study has found.
Scientists made the vaccine by fusing key proteins of the flu virus, made synthetically by genetic engineering technology, with a bacterial protein called ferritin that can automatically assemble itself into “nanoparticles” smaller than the virus. The flu proteins, which stick out from the ferritin like the spikes on a sea mine, stimulate immunity against the virus.
Normally, influenza vaccines are made by culturing live virus in hens' eggs, a risky and time-consuming procedure, but the new method was simpler and it produced a vaccine that appears to generate immunity to a wide range of flu viruses rather than being restricted to just one strain, scientists said.
The study, published in Nature, by a team led by Gary Nabel of the US National Institute of Allergy and Infectious Diseases in Bethesda, Maryland, said that the new vaccine could lead to broader immunity against new types of influenza viruses and other kinds of infectious agents that threaten to cause global epidemics.
“Standard vaccines rapidly lose efficacy, because the influenza virus is constantly mutating into new, unpredictable strains. The new vaccine works by stimulating the production of neutralising antibodies that latch on to parts of the virus that are common to different strains, which is a step towards the realization of a much sought-after universal vaccine,” says a statement from Nature.
“Made entirely from recombinant ingredients, it is also safer to make than standard vaccines, which are produced by growing the virus in eggs or cultured cells,” Nature says.
Professor Sarah Gilbert, a vaccine expert at Oxford University, said: “Overall, the study shows that it is possible to achieve broader immunity to influenza than that obtained with licensed influenza vaccines, which is an important step in the right direction, but there is a long way to go before this will make a difference to protecting people against influenza.”