Unique COVID-19 Vaccine Uses Modified Bovine Adenovirus to Provide Significantly Higher Levels of Immunity (B)

A team of scientists are working to develop a unique COVID-19 vaccine that uses a bovine adenovirus as a safe and effective delivery vehicle with the aim of protecting all segments of the population, especially older adults.

Adenoviruses have emerged as a promising gene-delivery platform for therapeutic and vaccine purposes. However, human adenoviruses are widespread and can cause common illnesses such as cold-like symptoms, fever, sore throat, bronchitis, pneumonia, diarrhea and pink eye. As a result, most people may have preexisting immunity that could impact the efficacy of vaccines delivered via a human-adenovirus-based vector.

Scientists at the Pennsylvania State University (University Park, PA, USA) have adapted an adenovirus typically found in cattle to prevent it from replicating, which enhances safety. The researchers have also modified the adenovirus to express a peptide that stimulates a robust immune response to influenza viruses in mice. According to the researchers, because SARS-CoV-2 is a newly emerged virus for which humans have no previous immunity, any vaccine will have to be highly immunogenic to provide protection, particularly among older adults, whose immune systems naturally decline with age.

"Our preliminary work has revealed that this novel vaccine platform provides significantly higher levels of immunity compared to that of human adenovirus vectors," Kuchipudi said. "We hypothesize that immunization with this vector expressing relevant antigens of SARS-CoV-2 will strengthen an effective anti-COVID-19 immunity," said Suresh Kuchipudi, clinical professor of veterinary and biomedical sciences and associate director of Penn State's Animal Diagnostic Laboratory.

"This work suggests that the bovine adenovirus vector system could serve as an excellent delivery vehicle for the development of recombinant vaccines against emerging pathogens — for the elderly and other segments of the population," added Kuchipudi. "We believe this effort will yield an effective COVID-19 vaccine and could make a significant contribution to flattening the pandemic's trajectory and helping to manage its second wave."

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