Ferrets will reveal if virus vaccines work

CSIRO scientists are starting the first stage of testing of two potential COVID-19 vaccines.
CSIRO scientists are starting the first stage of testing of two potential COVID-19 vaccines.

Ferrets at a high-security Victorian lab will determine if two potential coronavirus vaccines can proceed to human trials within months.

Australian scientists from the CSIRO have been trusted to determine if the two vaccine candidates are effective and safe enough to test on humans.

If all goes well with the ferrets, phase-one human trials could begin later this month or in early June.

But even then, a vaccine won't be widely available until the end of the year at the earliest.

"The end of the year would be an optimist's view. Early next year would be closer to the reality, all things working well," the CSIRO's director of health and biosecurity Rob Grenfell told reporters on Thursday.

The agency will spend the next few months working out if the candidates - developed by the University of Oxford and US company Inovio Pharmaceuticals - are effective and harmless.

The ferrets, deliberately infected at a high-containment biosecurity facility in Geelong, were vaccinated a few days ago.

They seem relatively well so far apart from having slight fevers.

"Eventually we will challenge the ferrets - we'll inoculate them with some of the virus and see how they compare to unvaccinated controls," said Professor Trevor Drew, the director of the CSIRO's Australian Animal Health Laboratory.

If the vaccines are effective, immunised animals should no longer shed the virus.

Scientists will also be looking for any sign the ferrets' health is worsening, with previous trials for the SARS virus showing vaccines can sometimes make a disease worse.

"When cells of the immune system see an infected cell, they tell it to kill itself. This can cause overt damage to the lung, if there are a lot of cells in the lung which are infected at that time," Prof Drew said.

"We need to be able to measure defence responses and make sure it does not cause overt damage."

The work the scientists are doing would usually take a couple of years. But the urgency of the pandemic means everything is being done safely, but at break-neck speed.

Several rounds of human trials will be required if the ferret trials are deemed successful.

The potential vaccines are among six to be tested around the world.

They were identified by Coalition for Epidemic Preparedness Innovations, in consultation with the World Health Organisation, as the most promising solutions to a virus that has infected more than 900,000 people and killed at least 45,000 globally.

Australia's Deputy Chief Medical Officer Paul Kelly has warned the virus will not be beaten without a vaccine, as the nation's number of diagnosed cases approaches 5000 with 23 deaths so far.

Asked how much hope people should have, Dr Grenfell said the world was seeing unprecedented cooperation among scientists and the public and private sectors.

"That, in itself, gives us a lot of hope."

Ferrets were chosen as the test animal because it has the right receptor cells in its lungs to allow infection, and has proven to be a suitable animal model in the past for research into SARS, influenza and even ebola.

Australian Associated Press