Cai Yujia, one of the researchers, recently told the South China Morning Post that if the team finds a partner to help them develop the vaccine, they will need three or four additional months of pre-clinical research before human trials can be conducted. They also showed antibodies to the adenovirus itself soared among people who had prior immunity, suggesting their systems views the vaccination as a boost of their Ad5 immunity.
The specific vaccines used in the second paper are preliminary, and may require considerable modification, but Barouch said in a statement, "Our findings increase optimism that the development of COVID-19 vaccines will be possible".
Monkeys develop immunity with vaccine after Covid-19 infection, studies show
"The global Covid-19 pandemic has made the development of a vaccine a top biomedical priority, but very little is now known about protective immunity to the SARS-CoV-2 virus", said senior author Dan Barouch, director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Boston. In order to probe whether infection with SARS-CoV-2 results in protective immunity against re-exposure, researchers developed a macaque model of SARS-CoV-2 infection that recapitulated certain aspects of human SARS-CoV-2 infection.
Currently, there are more than 100 candidate COVID-19 vaccines in development worldwide.More news: Outrage in Hong Kong as China pushes security law
They then proceeded to expose these monkeys and ten control animals were also exposed to the virus. All nine animals recovered and developed antibodies against the virus. Instead their viral loads started low and declined rapidly. "These data suggest that animals develop natural protective immunity against the virus and the disease that it causes".
Chen and colleagues examined the safety and tolerability of CanSino's non-replicating Ad5 vectored SARS-CoV-2 vaccine, which aims to induce sustained production of the virus's so-called spike protein antigen in recipients, in a dose-escalation phase I trial.More news: Ford Chicago SUV Factory Shut down again after Running Short of Seats
To test their immunity, they were exposed to SARS-CoV-2 again 35 days later for what is called a "re-challenge", and they showed few to no symptoms. In follow-up tests, the monkeys that were vaccinated with the coronavirus showed "dramatically lower viral loads" compared with the control group.
All of the macaques were infected with the new coronavirus six weeks after vaccination, and those that had received the real vaccines produced levels of antibodies in their blood that were high enough to neutralize the virus within two weeks.More news: Boris Johnson Will Not Face Criminal Investigation Over Relationship With Jennifer Acuri
"Rigorous clinical studies will be required to determine whether SARS-CoV-2 infection effectively protects against SARS-CoV-2 re-exposure in humans", they said. Although we don't yet know how long the protection lasts, or if the same will be true in humans, the work bolsters hopes for a vaccine and lowers the chances our worst fears about the virus will be realized.