Vaccine candidate protects monkeys from SARS-CoV-2 infection (Nature)
An experimental coronavirus vaccine Ad26 seems to have completely prevented infection in most monkeys that received the jab. Hanneke Schuitemaker at Janssen Vaccines and Prevention in Leiden, the Netherlands, Dan Barouch at Beth Israel Deaconess Medical Center in Boston, Massachusetts, and their colleagues gave 52 rhesus macaques (Macaca mulatta) a single dose of one of 7 vaccines (N. B. Mercado et al. Nature 2020). Each vaccine comprised a weakened respiratory virus coding for one of seven forms of SARS-CoV-2’s spike protein. After vaccination, nearly all the monkeys made neutralizing antibodies — powerful immune molecules that can block infection — and T cells that trigger other immune responses. When monkeys were exposed to SARS-CoV-2, the most potent of the vaccines Ad26 prevented lung infection in six out of six animals that received it using intratracheal route, and nasal infection in five out of six.Across all the vaccinated monkeys, levels of neutralizing antibodies were associated with protection from SARS-CoV-2 infection, but levels of T cells were not. The optimal Ad26 vector-based vaccine for SARS-CoV-2, termed Ad26.COV2.S, is currently being evaluated in clinical trials.