Lothar Stitz: A Vaccine for Every Strain of the Flu
Speed is essential to halting a flu pandemic. Lothar Stitz, a professor of veterinary medicine who researches virology and immunology at Germany’s Friedrich Loeffler Institute, has come up with a method to produce flu vaccines in weeks rather than months. Better yet, his vaccine may provide lifelong protection. “This could be a vaccine that covers all influenza strains,” he says.
One challenge in making flu vaccines has been that the virus constantly evolves through genetic mutation. Before scrambling to make enough flu shots to go around, scientists have to predict which strains will strike in the coming year. Most vaccines are grown inside chicken eggs and cell cultures, a process that can take more than six months.
Stitz, 63, hit upon his approach after hearing that a group of his colleagues, led by Ingmar Hoerr, was using messenger RNA (mRNA)—a genetic material that controls protein production—to develop a cancer vaccine. When he asked them about collaborating, he says, “they were a little bit astonished by the idea of using their method for infectious disease.”
The immune system has two major mechanisms for overcoming the flu. The first is an antibody response, triggered when the immune system recognizes proteins specific to the flu virus. This happens either as the body is fighting off a flu infection, because the patient has previously contracted that particular flu strain, or because the patient received a vaccine specific for that version of the virus. The second is cell-mediated immunity, in which the body’s T-cells are activated to recognize and attack cells infected by the flu virus.
Traditional flu vaccines are set up to trigger only the antibody response. Stitz’s mRNA vaccine, which can be produced in just six weeks and stored at room temperature, induces T-cell-mediated immune reactions that attack all influenza strains in addition to triggering antibody reactions to specific strains. A medical professional administers the vaccine by injecting a patient with mRNA encoded to produce proteins that elicit the flu-fighting mechanisms. CureVac, a biopharmaceutical company founded by Hoerr, has raised $190 million to fund research on mRNA vaccines for both cancer and infectious diseases. “What I really like is that we’re not producing drugs, but rather giving the body information to produce its own vaccine,” Hoerr says.
Four years of clinical tests have shown that all mice, rats, ferrets, and pigs immunized using mRNA survived, even after being injected with deadly infectious diseases, Stitz says. Still, challenges remain. Stitz’s mRNA vaccine has similarities to DNA vaccines that proved effective in mice but less so in humans, says John Treanor, chief of infectious diseases at the University of Rochester (N.Y.) Medical Center.
Stitz is eager to continue the long research process. That’s the reason he went into immunology rather than becoming a vet. “I thought this would be much more exciting than looking into the ears of an old dog,” he says.