The Kiwi antivirus arms race
A vaccine has been held up as Aotearoa’s holy grail in the fight against coronavirus.
The virus only recently got to humans, skipping the species divide to circulate among a world population with no immunity.
With New Zealand in quarantine, Kiwis heard a vaccine was the way back to to normality.
The other possibility is an effective antiviral, University of Otago public health professor Michael Baker said.
‘‘Actually, either or would be enough. Of course a vaccine would be useful, but the three biggest killers on the planet [HIV/Aids, tuberculosis, and malaria] we don’t have vaccines, for any of them, that are good.’’
But where does one start looking for vaccines and treatments?
Scientists have gone out with every technique they can think of, and are hoping to adapt existing tools to a novel enemy.
It’s probably the first time vaccines have been developed while we learn how a virus works and induces immunity, University of Auckland vaccinologist Dr Helen PetousisHarris said.
Much attention is on the virus’s spike protein – it sticks out and hooks onto cells to infect.
Stop that and you stop the virus, said Petousis-Harris, who also chairs WHO’s global advisory committee on vaccine safety.
Knowledge of that can feed into the nucleic acid vaccine approach ‘‘almost like dial-a-vaccine,’’ she said.
Take previous work on a MERS vaccine, replace genetic code for the MERS spike protein with that of the Covid-19 virus and you’ve got a potential vaccine.
That’s why the first vaccine candidate, by Moderna, went into an arm about 45 days after the release of the virus’s genetic sequence, she said.
There are at least 170, maybe more than 200 potential vaccines under development. Petousis-Harris lost count.
Approaches to creating immunity boil down to four broad categories: viral vaccines, protein-based, viral vectors, and nucleic acid vaccines.
Some vaccines will fail, but Petousis-Harris thinks we’re more likely than not to find something that works.
The virus is relatively stable, the best and brightest minds are collaborating, and there’s money available.
Even if New Zealand doesn’t develop a vaccine, it could help with manufacturing. Once one’s successful, we’d need about 70 per cent of people to be vaccinated, she said.
But we also need treatment for people who get the virus.
If we’d had antivirals for SARS in 2003 or MERS in 2012 we’d be in a good position, University of Otago virologist Miguel Quin˜ ones-Mateu said.
But research funding disappeared when those viruses were out of the spotlight.
We’re looking to retrofit drugs we already use – maybe using several together, University of Otago senior lecturer Christopher Gale said.
‘‘That’s quick, that’s a little bit dirty, it’s a little bit fast. But if we get an answer doing simple, small, quick studies and not spending millions of dollars to get a solution, no-one’s going to care.’’
‘‘If somebody can then find an elegant cure, we would love it. But until we get elegant, we will do cocktails, recipes that work.’’
Those hunting for Covid-19 treatments will look at the type of virus, how it attacks the body, its effects, and the immune response – then look for existing treatments used in similar circumstances, including in the animal world.
We need to prove their worth with hard numbers from trials with hundreds of people, removing human factors like doctors’ hopefulness, or people being in a facility which gives great standard care.