The new vaccine can be produced in a few weeks. Tests on mice show that immunization also works in young and old rodents. But it could take years before tests for a human vaccine are carried out.
Researchers at the Friedrich-Loeffler Institute (FLI), Germany's Research Institute for Animal Health, in collaboration with biotech company CureVac, have developed a new type of flu vaccine. The vaccine is based on messenger ribonucleic acid (mRNA), which controls the production of proteins.
The new vaccine was successfully tested on mice, ferrets and pigs. Mice showed remarkable immunity against the flu for their whole lives, according to the findings recently published in the journal "Nature Biotechnology."
The synthetic vaccine also takes less time to produce - a few weeks compared to six to nine months for conventional vaccines, which are grown in chicken eggs or cell cultures.
"For a conventional vaccine, one has to isolate the virus, cultivate it and let it grow until there are large amounts," FLI head of immunology Lothar Stitz told DW.
For this synthetic vaccine, we only need the genetic information of the viruses, he added.
Every year, the World Health Organization compiles a list of viruses that are the most likely to spread and drug companies produce vaccines based on the organization’s assumptions.
But the synthetic vaccine could also be good for people who are allergic to chicken proteins. They normally have a severe reaction to conventional flu shots, and alternative DNA vaccines are not that attractive. Some scientists fear that DNA vaccines could disrupt gene regulation by changing human DNA.
More effective than other vaccines?
In the trials, animals developed antibodies as well as cell-mediated responses which activate blood cells such as killer T-cells that could destroy the pathogens (infectious agents).
That's clearly an advantage of the mRNA-principle, Stitz said.
Most flu vaccines consist of antibodies targeting hemagglutinin (HA) and neuraminidase (NA), two proteins covering the surface of the virus. The antibodies neutralize the virus because they stop it from being able to dock at the cell. But the HA and NA are constantly changing, and this is why were are new flu shots every year.
But unlike the surface of the virus, the inside is pretty stable. And this is what the researchers are targeting because T-cells will respond to that inside protein no matter what the strain on the surface is. This is seen as a potential way of generating a universal flu vaccine.
It is surprising that these kinds of mRNA influenza studies have not been carried out before, said Bernhard Fleischer, head of the Department of Immunology at the University Medical Center Hamburg-Eppendorf.
"It's certainly a big step forward," he added.
Fleischer who was not involved in FLI's research said "it's a good study in a reputable scientific journal," while adding that it's worth following up on.
"Imagine how many eggs are needed to produce vaccines! And it's still quite expensive to create them in tissue culture," he said.
Previous attempts failed
This study isn't the first of a kind. There were attempts as early as fifteen years ago, but it was too difficult to stabilize mRNA, according to Stitz.
He believes that more research needs to be carried out. So far, he and his team have done tests on mice, ferrets and pigs.
Tests on mice, which have the shortest lifespace of the three animals, show that the vaccine also works in very young and old mice. That would mean that high-risk groups like newborns and the elderly would be better protected as well, if it has the same effect on people.
"I don't see any potential risks with mRNA at the moment, they have been well tolerated in cancer patients, but sometimes you only find out about those [risks] when it's being put to use. I assume it's going to take a long time though until the vaccines can be used on healthy human individuals," Fleischer told DW.
Chances are the vaccine won’t be hitting the pharmaceutical market very soon.
It will take years before such a vaccine is ready for licensing, said Klaus Cichutek, who heads the Paul-Ehrlich-Institut, Germany’s drug regulatory body.
"The hope for a universal vaccine has been around for years." he told DW. "Other studies with DNA vaccines have shown similar results. Unfortunately, this has not resulted yet in a clinical development of a universal vaccine."
The Institute is in favor of new developments that would shorten the production time, but the research is still in its initial stages, he added.
"We would appreciate it if the next paper included challenge studies in ferrets which react to influenza in a similar way as humans do," he said.