A highly effective bacteriophage-based COVID-19 mucosal vaccine without needles or adjuvants

New research shows needle-free T4 mucosal bacteriophage (phage)-based COVID-19 vaccine is effective against SARS-CoV-2 infection. The results were published in mBio, an open access journal of the American Culture for Microbiology.

In recent years, the Food items and Drug Administration authorized SARS-CoV-2 vaccines based on mRNA and adenovirus. These vaccines are injected intramuscularly in 2 or more doses and are effective in preventing COVID-19, but they do not induce effective mucosal immunity or prevent viral transmission.

In the new study, lead study authors Venigalla B. Rao, Ph.D. of the Bacteriophage Medical Research Center, Department of Biology , Catholic University of America, Washington, DC, and Ashok K. Chopra, Ph.D. CSc, Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, and colleagues report the first non-infectious mucosal vaccine based on bacteriophage T4, multicomponent, without needle or adjuvant. Both lead authors are elected members of the American Academy of Microbiology.

In experiments conducted in mice, intranasal administration of 2 doses of the T4-phage vaccine COVID-19 at 19 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 several variants and elicited Th1-biased cytokine responses, strong CD4+ and CD8+ T-cell immunity, and high titers of secretory IgA in sera. and 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 safety and sterilizing immunity against the mouse-adapted SARS-CoV-2 MA10 strain, the ancestral strain WA-1/ 2020 and the deadliest Delta variant in mouse models.

In addition, the T4-COVID-19 elicited broad virus-neutralizing antibodies against SARS-CoV-2 variants in serum and bronchoalveolar lavage, did not affect gut microbiota, exhibited minimal lung damage in mice vaccinated and challenged and is stable at room temperature.

“This intranasally administered vaccine generates superior mucosal immunity in mice in addition to inducing humoral and mediated immune responses. robust cells, and provides complete protection and sterilizing immunity against SARS-CoV-2 variants. The vaccine is stable, adjuvant-free and inexpensive. efficiently manufactured and distributed, making it a strategically vital next-generation COVID-19 vaccine to end this pandemic,” said Drs. Rao and Chopra. “This modular, needle-free, T4 phage mucosal vaccine delivery platform is a great candidate for designing effective mucosal vaccines against other respiratory infections and for emergency preparedness against emerging epidemic and pandemic pathogens.” .

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