Seasonal flu is an acute respiratory infection caused by influenza viruses that circulate the globe.
The typical signs and symptoms of seasonal flu include fever, cough, headache, muscle pain, sore throat, and a runny nose. Most people can recover from a fever and other symptoms within a week without requiring medical attention.
However, hospitalization and death may occur among high-risk groups such as children, older people, pregnant women, and people with chronic health conditions.
Annual flu shot
According to the World Health Organization, seasonal flu has caused about 3 to 5 million cases of severe illness worldwide, resulting in 290,000 to 650,000 deaths every year.
One of the effective ways to prevent the disease is vaccination.
Due to the continuously evolving nature of flu viruses, current vaccines need to be reformulated every year to well-match mutated viral proteins and different viral strains.
New universal flu vaccine
To protect a person against multiple viral strains, researchers from the University of Pennsylvania in the United States developed a universal modified-RNA flu vaccine by triggering a strong antibody response to a structure on the surface of flu viruses, called the hemagglutinin stalk.
When injected into a body, these special RNAs are absorbed by cells of the immune system and then translated into copies of the hemagglutinin protein to mimic a real flu infection and elicit a strongly protective antibody response.
More surprisingly, these new universal flu vaccines do not rely on the chicken egg-based manufacturing process that has been used for over 70 years for traditional flu vaccines. This provides a highly scalable, inexpensive, and favorable safety manufacturing way to produce flu vaccines.
The research was supported by the National Institute of Allergy and Infectious Diseases and Centers for Influenza Virus Research and Surveillance, and the research team published their results in Nature Communications.
Strong antibody responses in animal studies
The researchers continued to investigate antibody responses using animals. Only after receiving one injection of the new universal flu vaccine, the animal subjects showed a strong immune response to different flu virus strains such as H5N1.
The new universal flu vaccines open new doors to reshape the future of seasonal flu protection by providing a more potent effect based on the combination of antigens. Further studies should be done in clinical trials to fully assess the safety and efficacy before these vaccines can be launched to the market.
Reference: Pardi, N. et al.Nucleoside-modified mRNA immunization elicits influenza virus hemagglutinin stalk-specific antibodies. Nature Communications.2018;9:3361. DOI: 10.1038/s41467-018-05482-0.
