The scourge of the influenza virus devastates health and claims many lives worldwide each year. It is especially daunting because vaccines are only protective when they are well matched to the strains circulating in the population. But now, a team led by researchers at the Icahn School of Medicine at Mount Sinai is getting closer to a universal flu vaccine using a novel approach they've developed called chimeric hemagglutinin (cHA).
A protein on the surface of influenza viruses, hemagglutinin, shepherds the virus into host cells. Hemagglutinin is comprised of a 'head' (variable) and a 'stalk' (varies less from strain to strain). Thus, Icahn School of Medicine researchers, led by Peter Palese, Ph.D., Professor and Chair of Microbiology and Florian Krammer, Ph.D., Professor of have focused their efforts on developing a vaccine against the stalk portion of this protein. Their study, undertaken in collaboration with PATH, an international nonprofit, the Cincinnati Children's Hospital Medical Center, the Duke Early Phase Clinical Research Unit, and the University of Chicago, involved testing of several cHA-based vaccination regimens to see if they would induce antibodies that provide broad protection against influenza virus infections. The results were published this month in The Lancet Infectious Diseases.
The diverse research team including Adolfo García-Sastre, Ph.D., Professor of Microbiology and Director of the Global Health and Emerging Pathogens Institute at Icahn; Bruce Innis, M.D., Leader, Respiratory Infections and Maternal Immunizations at PATH; and Patrick Wilson, Ph.D., Professor of Medicine at the University of Chicago, have investigated whether several potential cHA-based vaccines might induce antibodies that would target the stalk of group 1 hemagglutinin-expressing influenza viruses. An adjuvant, an ingredient that boosts the effectiveness of vaccines, was also part of the testing process.
Vaccine regimens examined included: 1) a group receiving a chimeric H8/1 hemagglutinin-based live attenuated vaccine followed by a boost with a non-adjuvanted chimeric H5/1 hemagglutinin-based inactivated vaccine (IIV), and 2) the same regimen but with the IIV having an adjuvant called AS03, and 3) a prime-boost regimen including an adjuvanted cH8/1 IIV prime followed by an adjuvanted cH5/1 IIV boost.
The researchers found that the IIV, but not the live attenuated vaccine, induced a significant antibody response after the prime, with a strong increase in anti-H1 stalk titers. All vaccine regimens induced detectable H1 stalk antibody responses after receiving boosts.
"The vaccine induced a broad antibody response which was not only cross-reactive for currently circulating human influenza virus but also to avian and bat influenza virus subtypes," said Florian Krammer. "It was surprising to find that the inactivated formulation with adjuvant induced a very strong anti-stalk response already after the prime suggesting that one vaccination might be enough to induce protection against pandemic influenza viruses yet to arise. The results indicate that we are moving towards a universal influenza virus vaccine, but these are still interim results. Additional results will be available upon completion of the study at the end of 2019."
The University of Chicago performed crucial testing; funding was provided by a grant from the Bill & Melinda Gates Foundation. GlaxoSmithKline contributed some of the vaccines and adjuvants. Foundational support was provided by the by the National Institute of Allergy and Infectious Diseases.
About the Mount Sinai Health System
The Mount Sinai Health System is New York City's largest integrated delivery system, encompassing eight hospitals, a leading medical school, and a vast network of ambulatory practices throughout the greater New York region. Mount Sinai's vision is to produce the safest care, the highest quality, the highest satisfaction, the best access and the best value of any health system in the nation. The Health System includes approximately 7,480 primary and specialty care physicians; 11 joint-venture ambulatory surgery centers; more than 410 ambulatory practices throughout the five boroughs of New York City, Westchester, Long Island, and Florida; and 31 affiliated community health centers. The Icahn School of Medicine is one of three medical schools that have earned distinction by multiple indicators: ranked in the top 20 by U.S. News & World Report's "Best Medical Schools", aligned with a U.S. News & World Report's "Honor Roll" Hospital, No. 12 in the nation for National Institutes of Health funding, and among the top 10 most innovative research institutions as ranked by the journal Nature in its Nature Innovation Index. This reflects a special level of excellence in education, clinical practice, and research. The Mount Sinai Hospital is ranked No. 14 on U.S. News & World Report's "Honor Roll" of top U.S. hospitals; it is one of the nation's top 20 hospitals in Cardiology/Heart Surgery, Diabetes/Endocrinology, Gastroenterology/GI Surgery, Geriatrics, Gynecology, Nephrology, Neurology/Neurosurgery, and Orthopedics in the 2019-2020 "Best Hospitals" issue. Mount Sinai's Kravis Children's Hospital also is ranked nationally in five out of ten pediatric specialties by U.S. News & World Report. The New York Eye and Ear Infirmary of Mount Sinai is ranked 12th nationally for Ophthalmology, Mount Sinai St. Lukes and Mount Sinai West are ranked 23rd nationally for Nephrology and 25th for Diabetes/Endocrinology, and Mount Sinai South Nassau is ranked 35th nationally for Urology. Mount Sinai Beth Israel, Mount Sinai St. Luke's, Mount Sinai West, and Mount Sinai South Nassau are ranked regionally.