Booster for flu and other respiratory disease vaccines developed by Mass General researchers

BOSTON – An adjuvant has been developed that boosts the efficacy of vaccines for the flu and possibly coronavirus as well.  A study by Massachusetts General Hospital Researchers (MGH) has shown that this adjuvant/immune booster given along with a flu vaccine can make the shot much more effective against a wider range of strains than any single vaccine is usually protective against. This booster, which activates both immune and non-immune cells in the lung, could possibly be useful for vaccines against coronaviruses, such as COVID-19, as well.

The study’s lead author is Ji Wang, PhD, and it comes from the laboratory of Mei X. Wu, PhD, an associate professor at Harvard Medical School.  Their research was recently published in Science.

The study describes a pulmonary surfactant (PS) biomimetic liposome encapsulating cGAMP – an agonist of interferon gene inducer STING (Stimulator of Interferon Genes). This adjuvant, called PS-GAMP, greatly enhanced natural immune responses in mice without excess lung inflammation and provided protection against a range of flu strains, including H1N1, H3N2, H5N1, and H7N9. Most flu vaccines only protect against a single strain, so this adjuvant/vaccine booster might be able to vastly increase the effectiveness of a vaccine. 

Despite active vaccination program nationwide, the CDC estimates that up to 31 million Americans have caught the flu this season, with 210,000 to 370,000 flu sufferers hospitalized because of the virus. At least 12,000 people have died from influenza between Oct. 1, 2019 through Feb. 1, 2020, and the number of deaths may be as high as 30,000. Meanwhile, about 125,000 people have been infected with the new coronavirus (COVID-19) worldwide since it was first observed and more than 4,500 have died from it.

One of the biggest problems with current influenza vaccines is that they only protect against certain similar strains of the virus, which is constantly mutating.  In fact, influenza has been described as an “ever-evolving target” for vaccine development, which is why the vaccine must be tweaked to address the most prevalent strain every year. This will likely be a problem with COVID-19 vaccines as well.

Current influenza vaccines work primarily by inducing molecules called antibodies that target specifically for surface proteins  (hemagglutinin and neuroamidase) on the virus.  But these surface viral proteins  undergo what is called “antigenic drift” and so the target for any single vaccine is continually shifting.

The MGH-developed adjuvant augments both  T cells (CD8+ resident memory T cells) in the lung and the production of antibodies systemically.  The lung resident memory T cells  are able to clear multiple strains of viruses where they initially enter the lungs as early as possible, which minimizes lung damage.

About the Massachusetts General Hospital
Massachusetts General Hospital, founded in 1811, is the original and largest teaching hospital of Harvard Medical School. The MGH Research Institute conducts the largest hospital-based research program in the nation, with an annual research budget of more than $1 billion and comprises more than 8,500 researchers working across more than 30 institutes, centers and departments. In August 2019 the MGH was once again named #2 in the nation by U.S. News & World Report in its list of "America’s Best Hospitals."