Vaccine candidate tested in monkeys
Global spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to an urgent race to develop a vaccine. Gao et al. report preclinical results of an early vaccine candidate called PiCoVacc, which protected rhesus macaque monkeys against SARS-CoV-2 infection when analyzed in short-term studies. The researchers obtained multiple SARS-CoV-2 strains from 11 hospitalized patients across the world and then chemically inactivated the harmful properties of the virus. Animals were immunized with one of two vaccine doses and then inoculated with SARS-CoV-2. Those that received the lowest dose showed signs of controlling the infection, and those receiving the highest dose appeared more protected and did not have detectable viral loads in the pharynx or lungs at 7 days after infection. The next steps will be testing for safety and efficacy in humans
The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in an unprecedented public health crisis. Because of the novelty of the virus, there are currently no SARS-CoV-2–specific treatments or vaccines available. Therefore, rapid development of effective vaccines against SARS-CoV-2 are urgently needed. Here, we developed a pilot-scale production of PiCoVacc, a purified inactivated SARS-CoV-2 virus vaccine candidate, which induced SARS-CoV-2–specific neutralizing antibodies in mice, rats, and nonhuman primates. These antibodies neutralized 10 representative SARS-CoV-2 strains, suggesting a possible broader neutralizing ability against other strains. Three immunizations using two different doses, 3 or 6 micrograms per dose, provided partial or complete protection in macaques against SARS-CoV-2 challenge, respectively, without observable antibody-dependent enhancement of infection. These data support the clinical development and testing of PiCoVacc for use in humans
The serious COVID-19 pandemic and the precipitously increasing numbers of deaths worldwide necessitate the urgent development of a SARS-CoV-2 vaccine, and this requires a new pandemic paradigm. Safety and efficacy are essential for vaccine development at both preclinical studies and clinical trials. Although it is still too early to define the best animal model for studying SARS-CoV-2 infections, rhesus macaques, which mimic COVID-19–like symptoms after SARS-CoV-2 infection, appear to be promising candidates. We provide evidence for the safety of PiCoVacc in macaques, and did not observe infection enhancement or immunopathological exacerbation in our studies. Our data also demonstrate complete protection against SARS-CoV-2 challenge with a 6-μg dose of PiCoVacc in macaques. Collectively, these results suggest a path forward for the clinical development of SARS-CoV-2 vaccines for use in humans. Phase I, II, and III clinical trials with PiCoVacc, as well as other SARS-CoV-2 vaccine candidates, are expected to begin later this year.
Reference & source information: https://science.sciencemag.org/
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