If we let up, coronavirus toll will just spiral

Bodies are moved to a refrigeration truck serving as a temporary morgue at a New York hospital in April. Picture: AFP

We stand at a dangerous crossroads in the fight against COVID-19. The outbreak in Victoria is less our second wave than our first wave of community transmission. Despite its mistakes, the Victorian government’s lockdown actions are sensible and necessary.

Australia faces a potential health disaster. The next week or two are critical.

Five weeks ago, Victoria reported zero daily new infections. It has now had 10 days of more than 100 new infections and five of more than 200. The daily figure of 240 could be a peak, or the base camp for further rises. Plus there is the worrying Sydney outbreak.

One of the areas where the Victorian government has performed poorly is contact tracing. Several hundred new cases a day puts enormous strain on contact tracing. It could become impossible.

There is silliness by those who deny the seriousness of the coronavirus. Bits of data are cherrypicked, and outlier studies quoted as authoritative. Even outrageous propaganda by some foreign ­governments is cited if it fits the prejudice. So where are we really?

First, let’s tackle the nonsense of herd immunity. This is the goal of those who think we should try to protect the most vulnerable, practice a few hygiene measures and otherwise let the disease rip in the hope that it will infect and kill enough of us that it will eventually be unable to find new victims and will go away.

Raina MacIntyre of the University of NSW is one of Australia’s most distinguished epidemi­ologists and has spent her life working on these matters. She says herd immunity is impossible without a vaccine.

I asked federal Health Minister Greg Hunt about it. He answered and checked back with the best scientific advice. He said, correctly, that no country or territory had achieved herd immunity.

He added: “Herd immunity is completely unrealistic. First, it would only work if there was a prolonged or permanent immunity. And that’s not certain. Even so, you would need 60 per cent of Australians (15 million) infected. If the fatality rate of those infected is 1 per cent, that’s 150,000 deaths (to achieve herd immunity). If the fatality rate of those infected is 1.5 per cent, that’s 225,000 deaths. That strategy doesn’t survive first contact with reality.”

Hunt says the death rate from COVID-19 in developed countries with excellent health systems is about 1 per cent of those infected. Australia with 111 deaths and more than 10,000 infections is a little over that, more or less what the evidence internationally suggests.

MacIntyre says herd immunity was a concept developed in the context of vaccination. There are very few diseases where herd immunity can be achieved naturally. Had it been naturally achievable there would have been no need for smallpox vaccinations.

The herd immunity for a disease varies according to its reinfection rate — how many people each infected person will go on to infect. There are fairly precise mathematical formulas that predict when herd immunity cuts in.

MacIntyre agrees with Hunt that to achieve herd immunity would require more than 60 per cent of us to be infected.

She says: “Even at 5 per cent, the whole society collapses, the hospitals are full and overflowing, trucks are lining up to collect the bodies, ice rinks are converted into morgues.”

The bottom line is that there is absolutely no reason why our cities could not end up replicating the worst experiences of US cities. The only reason we won’t do that is ­because of the strong actions that we have taken and are taking.

Here is where the debate between economics and health can become a bit surreal. Certainly, governments must balance how much to shut down and when and how often, and the health benefits this brings — that is to say, fewer dead people — against the costs. But be under no illusions. If Australia came near 10 per cent of the population with active infections, say 2.6 million infections and 26,000 deaths, we would be screaming for the strongest possible government action.

MacIntyre thinks parts of the debate have been so unrealistic ­because so few Australians have been affected by the tragedy.

She is also clear that the research indicates that immunity in any event will not be permanent. Both Hunt and MacIntyre are ­optimistic about getting a vaccine. Hunt warns it likely won’t give permanent immunity. MacIntyre is even stronger on that point. The history of coronaviruses is people get them over and over again after immunity wears off. Even when antibodies are gone, there is some memory in T-cells in the blood and this might be of modest help, but there is no indication this gives or could give lifelong immunity.

Any vaccine will likely resemble a flu vaccine. It substantially cuts down your chances of an infection and it reduces the ­severity of it if you are infected. It doesn’t give you 100 per cent protection in the short term nor protection in the longer term. You generally need the jab each year.

Whether we had been pursuing eradication or suppression would have made no difference to the Victorian outbreak because it came mainly from mismanaged quarantine hotels.

And we are going to need quarantine hotels at least until we see a vaccine. Even after a vaccine, we probably cannot allow large numbers of international travellers to come unless they have credible, recent vaccination certificates. And without a vaccine, we cannot allow anyone to come unless they quarantine for two weeks.

Assuming immunity is short term, there is every chance that once a society gets through the virus it is susceptible again shortly later. Coronaviruses are much more stable than flu viruses, although, even without a vaccine, treatments that reduce the death rate are improving.

But still about 20 per cent of those infected need hospitalisation or they will likely die. Hundreds of health workers have died across the world (and that doesn’t happen even in bad a flu season). If we don’t get it right, the worst is ahead of us. And if we do get it right, life will still be very different for a very long time.