Talking Point: Extraordinarily optimistic to imagine large-scale immunity in less than two years

MARTYN GODDARD: Vaccine is unlikely in under 15-18 months, so what does Tasmania do about the virus until then?

CROWDS: Salamanca Market on March 14. Picture: Matt Thompson

With our island in near-lockdown, two vital questions remain not only unanswered but barely even asked. How long can we keep this up? And what happens when the restrictions are lifted?

Globally, the containment strategy is aimed not at eliminating the virus — that is now all but impossible — but to slow its spread so health systems can cope. In that vastly oversimplified graph we’ve all seen, it’s shown as “flattening the curve”.

The idea is that without intervention, infections will rise exponentially until so many people have been infected and become immune that the chance of an uninfected person catching the disease gets less and less. That’s called herd immunity. Under this scenario, the peak ends quickly but at the cost of overwhelming the health system and causing the deaths of people who cannot be treated. The stated aim of the restrictions is to slow the rise in new cases to a level at which the hospitals and clinics can cope. This results in a longer outbreak but allows everyone to be treated.

Both these cases rely on a similar number of people becoming infected, recovering and developing immunity to reduce the outbreak to a much lower, possibly permanent, level. This is not what’s happening in Tasmania. We began with a tiny number of infectious people coming from elsewhere and with little or no discernible community transmission within the state. The controls now in place are likely to keep the number of cases extremely low and, conceivably, eliminating it here altogether.

That would be the best possible outcome if we could keep the controls going until a vaccine is available and a large proportion of the population immunised. But we can’t.

The Prime Minister has said restrictions are likely to last for up to six months. But most expert predictions are that a vaccine is unlikely to be developed, trialled and approved in less than 15 to 18 months. Then manufacturing will have to be ramped up to a massive scale and the vaccine — there may be more than one — distributed globally.

And, of course, they will have to be paid for. There will be worldwide competition for initially restricted supplies, and pharmaceutical companies have a history of charging as much as they can get away with. It would be extraordinarily optimistic to think vaccine-induced immunity can be achieved on a large scale in Tasmania in less than two years.

Meanwhile, the virus will not have gone away. If interstate and overseas travel resumes before then, and internal restrictions are even partly lifted, it will return to a community with no natural immunity and no vaccine.

Although the health system might by then be in a better position to cope, the result would still be disastrous. The community might then resist reimposition of lockdown measures that had caused economic mayhem with little apparent result. We are not engaged in a war, but a principle of war nevertheless applies. Don’t start on a course of action without an exit strategy. What’s ours?

Martyn Goddard is a public policy analyst specialising in health.