In a recent study published in Cell Host & Microbe, researchers found that a novel, gene-based COVID-19 vaccine was highly effective at eliciting neutralizing antibody responses and cellular immunity from a single dose.
The vaccine provided nonhuman primates near-complete protection against a live SARS-CoV-2 viral challenge.
The AAVCOVID vaccine was shown to be producible with efficient, scalable, and industry-established manufacturing processes.
The team further showed that the vaccine product is stable at room-temperature storage conditions for up to one month, facilitating potential future distribution of the vaccine.
The study is from Mass Eye and Ear. One author is Luk H. Vandenberghe, Ph.D.
In the study, two AAVCOVID vaccine candidates with different SARS-CoV2 virus spike-based antigens were analyzed in a battery of experiments to measure effectiveness, duration of response, potency and stability.
The candidates were derived from genetic data collected on the Wuhan strain of the SARS-CoV-2 virus.
One vaccine candidate, AC1, was found to be superior in its ability to produce sustained immune responses in mouse and nonhuman primate models.
Next, to gain a better sense of how the vaccine might work in people, the AC1 AAVCOVID candidate was studied in a nonhuman primate model.
The team found The AC1 vaccine led to antibody levels that peaked at week 11 and remained at peak for at least 11 months.
The antibodies were detected in lung tissues, which may suggest mitigating some of the pulmonary effects of COVID-19 infection. The vaccine also induced long-term functional memory T-cell responses.
No adverse effects were observed in either animal model.
Further testing established the feasibility of large-scale manufacturing of the vaccine is already available in industry processes through Novartis Gene Therapies.
The researchers also tested cold-chain storage requirements, or the need to keep the vaccines at specific low temperatures to retain potency.
They analyzed the vaccine’s potencies when stored at -112⁰F (-80⁰C), 39⁰F (4⁰C) or 77⁰F (25⁰C) to approximate freezing, refrigerated and room temperatures, respectively.
The vaccine was shown to be stable after one month at room temperature, with stability at colder temperatures exceeding three months.
The team says the remarkable efficacy induced in the nonhuman primate model after a single injection of the AAVCOVID vaccine does represent an important step in the development of a COVID-19 vaccine.
The different variants of COVID-19, including the Delta variant, were also neutralized by serum from the AC1 candidate in vaccinated animals.
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