Walkabout

19 August 2021

by George Santayana

*Spoiler alert*: There is a moment in one of the Mad Max films where Max and his band of tagalongs have successfully escaped from their pursuers and are striking out through the post-apocalyptic Outback in search of The Safe Place, a haven of security where they hope to live out their lives in peace. After much struggle, they crest the top of an enormous dune only to see an endless desert stretching out beyond the horizon. It is as this point that the true nature of their predicament becomes clear; do they continue on alone into the unending sea of sand in what may be the forlorn hope of reaching The Safe Place, or do they stay where they are until their pursuers inevitably catch up with them, or do they turn around and head back into danger but to somewhere where they know there is water and shelter?

In many ways, this is an apt metaphor for the situation Australia and New Zealand now find themselves in with respect to Covid. Having apparently successfully escaped from the pandemic, what should they do now? Do they plough on in the hope of reaching some kind of Safe Place, which may or may not exist, or do they instead attempt to re-join the rest of the world?

A year ago, Australia and New Zealand were seen as lucky success stories; far enough from the epicentres of coronavirus infection and with limited points of global contact meaning that non-pharmaceutical interventions (NPIs) including border closures and harsh lockdowns prevented Covid from gaining a significant foothold in the countries. So, while Covid has raged around the world, within the walls of these antipodean fortresses people have remained largely untouched by SARS-CoV-2 and Covid.

What next?

Rationally, one would think that the endgame is clear, now vaccines are available: immunise the population and open the borders – many lives saved and a vindication of the isolationist strategy and the huge sacrifices this has required. The trouble is that the medical reality doesn’t square the political circle.

The first issue is that the very success in keeping Covid out of the country creates a vaccination problem because the prevalence of the disease is low. This means that there is no immediate incentive for people to get vaccinated against Covid because they are extremely unlikely to encounter an infected person and, as the current vaccinations against SARS-CoV-2 carry with them the low risk of severe adverse events, the balance of benefit/risk of these vaccinations for an individual Australian or New Zealander is, as of today, unfavourable. Simply put, with no virus in the country why should someone take the risk of an adverse event to be vaccinated against something that they will almost certainly not encounter and so cannot catch? This may partially explain why vaccine take-up has been so sluggish.

Of course, the vaccination aim is not to deal with the here-and-now, but to enable a future in which borders are opened. This leads to the second problem, which is that the vaccines themselves are not effective enough to meet the political promises, which rely on them producing effective herd immunity.

Vaccination creates immune memory, it does not produce some kind of ‘immune deflector shield’ that envelopes a person’s body and repels viral particles. So, vaccination does not stop infection from occurring, it just means the immune system of the individual getting infected responds more rapidly and effectively. For some vaccinations, the immune memory created, and its response to infection, can lead to a vaccinated, infected individual not becoming infectious, which in turn limits the spread of the disease. Vaccinate enough people with such a vaccine and you can effectively stop the spread of infection due to herd immunity.

But a vaccination does not need to be this effective to be useful. If the vaccination reduces the likelihood of someone developing significant disease, then preventing onward transmission of viral infection is desirable but not essential. The individual still benefits, but the broader ‘herd’ effects are greatly diminished. This situation is much closer to the truth with current vaccinations against SARS-CoV-2, which may not have much impact on viral transmission but do appear to reduce the incidence of serious disease. The trouble is that the operational verb here is “reduce”, meaning that even if the entire populations of Australia and New Zealand were vaccinated with these vaccines, once the borders opened, SARS-CoV-2 would enter and spread within their populations, and with it Covid.

So, what would a realistic scenario look like for the use of current vaccines in the re-opening of the borders in Australia and New Zealand? First, there would need to be a successful vaccination campaign prior to opening the borders that will inevitably throw up instances of individuals suffering from major side effects, including death. Perhaps people would be willing to accept this if they saw the long-term gains being worth it. But, given the lethargic vaccine uptake, perhaps exacerbated by the ‘no immediate benefit’ problem, it is much more likely that governments would have to introduce a range of incentives to ‘encourage’ vaccination. Vaccine passports, for example, would inevitably be on the agenda and how popular these would be is unclear, especially as they would need to coincide with the ongoing severe restrictions needed to keep the countries virus-free while vaccination takes place. Then there is the conundrum of when to decide that vaccination is good enough to allow the borders to be opened. Throw in variants and the question as to how long immunity lasts and it could be that there is never a point that vaccinations are good enough and Australians and New Zealanders will find themselves in an endless cycle of vaccinations and lockdowns. However, assuming we do reach a point of ‘good enough’, then once the borders start to open there will be a surge of Covid cases running through the population (probably being tracked and exaggerated by a mass screening campaign) together with an inevitable number of Covid-related deaths.

If the aim of the isolation/vaccination strategy was the reduction in serious disease/Covid-related mortality then the outcome of such a scenario is fine, although the methods of getting there are likely ethically bankrupt as they would almost certainly require coercion and compulsion. But given the current destruction of civil liberties, these may just be details. People will still get ill, and some will unfortunately die or suffer significant disease or have serious vaccine-related side effects, but these numbers will probably still be lower than would have died or been seriously ill with Covid if SARS-CoV-2 had got into the unvaccinated population. Of course, how many lives would have actually been saved by this approach would be a point of much debate and we’d have to rely on our old friend computer modelling to ‘prove’ that the pain was worth the gain. However, the real problem is that this strategy is political cyanide because the stated aim of the isolationist strategy is not to reduce the number of Covid related deaths per se but to have zero-Covid.

Achieving the zero-Covid nirvana relies on solutions that are either likely the stuff of medical fantasy or a very long way off. The first route to zero-Covid is the development of a perfect vaccine that is not only essentially 100% safe but also 100% effective against all SARS-CoV-2 variants, both now and in the future. This would enable robust herd immunity to be established in Australia’s and New Zealand’s populations with minimal risk to the population from the vaccination itself. God may well have arrived before this is ever developed. The second option is the ‘smallpox option’ which relies on the rest of the world somehow eliminating SARS-CoV-2 and Covid, thus removing the need for isolation. This is even less likely than the development of the perfect vaccine, because not only does it depend on developing something like the perfect vaccine against SARS-CoV-2, but also for this vaccine to be successfully deployed globally to eliminate the disease… an extremely unlikely possibility and even if were possible, it would take decades. Alternatively, we could hope that the disease naturally dies out on its own, which also seems vanishingly unlikely given that SARS-CoV-2 is now an endemic human pathogen in many regions. The only realistic scenario is not disease elimination but one in which the virus mutates into an ‘acceptably deadly’ form which could take decades or centuries – if not longer – if ever.

So, there you have it, just like Mad Max, none of the choices faced by Australia and New Zealand are palatable or risk-free. Do they plough on alone with the hope of reaching The Safe Place where vaccines have achieved perfection, or wait until the rest of the world has eliminated Covid or the disease has evolved into an acceptable risk? All the while accepting that they will need to continue to remain completely isolated while deploying draconian measures to try and maintain their virus-free status – with all the societal and economic damage this will cause. Alternatively, they can turn around and accept that they will likely never reach The Safe Place, accept the limitations and risks of current treatments, and use them as best as possible to re-join the rest of the world. A choice that means abandoning zero-Covid and swallowing a lot of political pride in bringing their populations with them on the return journey. The final possibility is, of course, the one in which the thing they are running from finally catches up and SARS-CoV-2 gets enough of a foothold in the country to render lockdowns and other NPIs ineffective at preventing its spread through the population. As it may be impossible to marry the political narrative with the scientific reality, this last scenario may become the inevitable end of the story.

George Santayana is the pseudonym of a senior executive at a British pharmaceutical company.