Excellent progress on vaccine

Vaccine work ‘amazing’ but . . .

IMPRESSIVE progress is being made on developing a vaccine to fight Covid19 but a safe end product is 12 to 18 months away at best, University of Otago infectious disease specialist David Murdoch says.

“That may seem a long way in the future, but it is worth remembering past vaccines have taken 10 to 15 years to get to market,” he said.

Prof Murdoch, dean of the University of Otago, Christchurch campus, has experience in vaccine evaluation and deployment and said he understood at least 35 vaccine candidates were entering various stages of development around the world.

“The fact clinical trials are starting is amazing when you think that four months ago we did not even know this virus existed.’’

Vaccines are developed through a sixstage process, including preclinical trials, clinical development, testing the immune response of volunteers and further testing to be sure of safety, effectiveness and dosage.

He was “quietly optimistic” a Covid19 vaccine would be developed in 12 to 18 months.

“Recent events, like the West African Ebola outbreak, really pushed on the technology.’’

The development process begins with an exploratory phase, in which scientists work out how to target the vaccine.

Live cells are then grown in the lab, or there could be testing on animals to examine immune response.

Prof Murdoch said a lot of vaccines failed at the preclinical stage but if a vaccine looked promising, it would enter clinical development, which was a threestage, expensive phase.

Phase 1 typically involved fewer than 100 healthy volunteers and the goal was to gauge the development of the immune response.

If successful, a vaccine would proceed to phase 2 trials, which might involve hundreds of volunteers and would enable scientists to refine dosage levels.

Thousands or tens of thousands of volunteers might be used in phase 3 placebocontrolled trials. Scientists would then study who developed the infection, comparing a control group with those who were vaccinated.

A vaccine would then be reviewed by regulators and approved, and progress to manufacturing.

“Thought needs to be given to that very early on. There is no point developing the vaccine if you cannot make enough,” Prof Murdoch said.