They launch a promising new needle-free nasal vaccine against COVID-19

New research has shown that the needle-free bacteriophage T4 (phage) COVID-19 vaccine is effective against SARS-CoV-2 infection. The results were published in “mBio,” an open access journal of the American Society for Microbiology.

Health authorities have authorized SARS-CoV-2 mRNA and adenovirus vaccines during the pandemic. These vaccines are injected intramuscularly in two or more doses and are effective in preventing COVID-19, but do not induce effective mucosal immunity or prevent viral transmission. In the new study, lead authors Venigalla B. Rao, Center for Bacteriophage Medical Research, The Catholic University of America in Washington, and Ashok K. Chopra, Department of Microbiology and Immunology, University of Texas Medical Branch, both in in the United States, and colleagues report the first non-infectious bacteriophage T4-based, multicomponent, needle-free, mucosal adjuvant-free vaccine. Both lead authors were elected Fellows of the American Academy of Microbiology.

In experiments in mice, intranasal administration of 2 doses of the T4-COVID-19 phage vaccine 21 days apart induced robust mucosal immunity, in addition to strong systemic humoral and cellular immune responses. The intranasal vaccine induced broad titers of virus-neutralizing antibodies against multiple variants and elicited Th1-biased cytokine responses, strong CD4+ and CD8+ T cell immunity, and high titers of secretory IgA in serum and serum. bronchoalveolar lavage of vaccinated mice.

All of these responses were much stronger in mice vaccinated intranasally than those induced by the injected vaccine. Additionally, the nasal vaccine provided complete protection and sterilizing immunity against the mouse-adapted MA10 strain of SARS-CoV-2, the ancestral WA-1/2020 strain, and the more lethal Delta variant in mouse models.

Additionally, the T4-COVID-19 vaccine elicited broad virus-neutralizing antibodies against SARS-CoV-2 variants in serum and bronchoalveolar lavage, did not affect the gut microbiota, and showed minimal lung damage. in vaccinated and challenged mice. stable at room temperature. “This intranasally administered vaccine generates superior mucosal immunity in mice, in addition to inducing robust humoral and cellular immune responses, and provides comprehensive protection and sterilizing immunity against SARS-CoV-2 variants. The vaccine is stable, has no adjuvants, and is cost-effectively manufactured and distributed, making it a strategically important next-generation COVID-19 vaccine to end this pandemic,” explain Drs Rao and Chopra.

“This modular, needle-free, mucosal T4-phage vaccine delivery platform is an excellent candidate for designing effective mucosal vaccines against other respiratory infections and for emergency preparedness against epidemic pathogens. and emerging pandemics,” they conclude.

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