Study shows benefits, negatives of a universal flu vaccine

Nov. 3 (UPI) -- University of Rochester Medical Center researchers are working to develop a universal influenza vaccine that would protect against all strains of the flu.

The World Health Organization estimates that the flu impacts nearly 1 billion people worldwide, with 3 to 5 million cases resulting in severe infections and 300,000 to 500,000 deaths each year.

The research, published Monday in Scientific Reports, aims to target the whole hemagglutinin protein, covering the outside of the flu virus. Current flu vaccines target the head of the hemagglutinin protein, which constantly changes to evade immune defenses.

The hemagglutinin protein consists of a head and a stalk, similar to a flower, and the while the head changes, the stalk is relatively constant from one flu strain to another. So researchers believed the stalk was a good target to create an influenza virus with broader protection.

However, researchers at URMC New York Influenza Center of Excellence found that the stalk is also capable of alterations. Researchers used supercomputers to analyze the genetic sequences of human H1N1 flu viruses and found variations in the head and stalk.

"The good news is that it's much more difficult to drive mutations in the stalk, but it's not impossible," Dr. David Topham, professor in the department of Microbiology and Immunology at URMC, said in a press release.

Researchers paired H1N1 with human antibodies and found that repetitive exposure to the antibodies caused several mutations in the head, but very few changes in the stalk, showing that the stalk can change in response to influences from the immune system.

"A universal flu vaccine based on the stalk would be more broadly protective than the ones we use now, but this information should be taken into account as we move forward with research and development," Topham said.