H1N1 Gives Clues to Universal Flu Vaccine

The H1N1 pandemic flu caused a global panic when it first emerged in 2009, but researchers now say it could hold the key to vaccines that protect against a variety of influenza strains.

In a study published last week, scientists from the University of Chicago and Emory University found that patients infected with the 2009 H1N1 strain developed antibodies that are reactive to multiple strains of flu—an immune response that was previously considered quite rare.

The results act as a “proof of concept” that when given the right immunogen–or the right vaccine–the human body can defend itself from many flu strains, said Patrick Wilson, one of the authors of the study and a professor of medicine at the University of Chicago.

“The result is something like the Holy Grail for flu-vaccine research,” Wilson said.

The antibodies from the patients were reactive for all the seasonal H1N1 flu strains from the last decade, the “Spanish flu” strain from 1918, and a strain of the H5N1 avian flu.

Seasonal flu vaccines are reformulated each year to protect against the three influenza viruses public health officials predict will be most common. A universal flu vaccine, that could eliminate the need for individual flu strain vaccines, has long been sought in the fight against the illness, which kills thousands of people in the United States each year.

But such a vaccine would still take time to develop, perhaps five to ten years, said Wilson.

Peter Palese, chair of the department of microbiology at Mount Sinai School of Medicine, who was not involved in the study, said the results are an “important step” that indicates a pan-protective vaccine could be possible, but said it is “still some way off.”

“What is really new here is that there was a quantitation of how many of those cross reactive antibodies were made,” Palese said. “It’s very encouraging that people, humans, can make such antibodies in large quantities.”

The antibodies produced in the study are considered promising because they target a portion of the virus, the stalk, that is largely conserved across many types of influenza. These types of antibodies had been recognized in human immune response to flu strains before, but in much smaller quantities.

“Occasionally the antibodies that can bind to this stalk will arise but they are quite rare, so the surprise was people who had the pandemic influenza infection, over 10 percent of their antibodies were targeting this part of the virus,” said Wilson.

The study results were based on antibodies from a small cohort of nine patients, so the next step for the researchers will be expanding the number of patients and collecting a larger data set, he said.

Some of the antibodies were also tested in mice for the research and found to protect against several H1N1 strains, an important threshold, said Arnold Monto, a professor of epidemiology at the University of Michigan School of Public Health who has no ties to the study.