Saturday, 30 May, 2020

CanSino coronavirus vaccine appears safe in first human trial

New studies show monkeys infected with COVID-19 develop immunity, a positive sign for vaccines Experimental COVID-19 vaccine shown to be effective in monkeys
Gustavo Carr | 23 May, 2020, 05:35

"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.

The study found that one dose of the vaccine, tested at three different levels, appeared to induce a good immune response in some subjects.

Of course it would be vastly better if immunity could be generated by a vaccine.

The Chinese vaccine was the very first shot to enter clinical trials earlier this year - months ahead of human testing for the UK's lead candidate jab - made by Oxford University - or the American lead-contender, made by biotech Moderna.

Researchers sought answers to two urgent questions: whether vaccines will prevent the COVID-19 infection, also called SARS-CoV-2, and whether those who've recovered from COVID-19 are protected against reinfection if exposed again.

In another study, Barouch and his colleagues tested 25 monkeys with six prototype vaccines to see if antibodies produced in response were protective. All nine animals recovered and developed antibodies against the virus. It will also involve 500 adults, including participants older than age 60.

While any increase in neutralizing antibodies was a significant gain over the subjects' starting levels (zero), Dr Peter Hotez, a vaccine expert at Baylor College of Medicine in Texas, was unimpressed with the levels produced in the trial participants. Fever (46%), fatigue (44%), and headache (39%) were the most common systemic adverse events.

China to crack down on wild animal trade
Hunan and Jiangxi, which both border Hubei, have also set out plans to change livestock practices. Researchers believe that 70 percent of new diseases are coming to humans from animals.

"The Ad5 vectored COVID-19 vaccine is tolerable and immunogenic at 28 days post vaccination", the authors of the study wrote.

A Phase 2 trial has already begun in Wuhan that is randomized, double-blinded, and placebo-controlled.

Dr. Joanne Langley of the Canadian Center for Vaccinology in Halifax says CanSino's partnership with the National Research Council of Canada puts a spotlight on homegrown scientific expertise, and should guarantee a Canadian supply if the potential vaccine proves viable.

With only four or five animals getting each vaccine, comparisons need to be treated with caution, but the monkeys receiving certain vaccines showed dramatically lower levels of virus throughout their bodies compared to the controls. "It's only a Phase 1 study".

"This is the story of Ad5", Edwards said.

"Maybe this level of antibody is enough?" "I think it's reasonable to look at this and see what it does".