COVID-19 crossing the Rubicon

As far as I can make out, Australia is now fully committed to a policy of "Adapt and Control" as opposed to "Eradicate".

This means infection rates will continue to grow, at first gradually and then suddenly.

The intention is to avoid the hospitals being overwhelmed while gradually lifting restrictions to get people back to work.

There is already an increase in the reproduction rate, "R", above 1, from the reduced physical distancing that inevitably followed the announcements of success and plans to remove restrictions. It started rising weeks ago, which was triumphantly announced as still being below 1.

That growth is starting from a very low rate of community transmission, so the growth will initially again be "gradual". But community transmission means untrackable and uncontrolled transmission. "Community" transmission is not stopped by testing and contact tracing because the carriers are often pre-clinical and don't get tested. It is only limited by physical distancing preventing transmission. Lifting the restrictions simply means there is nothing to prevent community transmission growing again, at first gradually and then suddenly. This shows up weeks later as the numbers of known cases growing gradually and then suddenly and later still for the numbers of deaths.

Opening the schools removes the main obstacle to getting people back to work and at the same time opens a channel for wider spread of infections among households via schools even while the faster transmission between households via workplaces remains restricted.

As infected school children tend to have mild or no symptoms it is likely that they are less infectious and so transmission between them in schools would be relatively slow compared with transmission between adults at workplaces. That has been presented as though a slow rate of transmission means a decline in cases – with "evidence" such as the low numbers of clusters among school children and of household transmission from children to adults. But we don't know much about mild or asymptomatic cases because pre-clinical cases obviously do not get much clinical study since they don't seek clinical assistance. If some of them last longer than more severe cases that trigger an immune system response or result in long term carriers, then a slow rate of transmission can still result in a larger than 1 rate of reproduction, sufficient to cause a (slower) epidemic.

But we don't actually even know whether or to what extent infected children are less infectious than infected adults. Droplets are the main source of contagion, direct and via surfaces with transfer from hands to face. One would certainly expect that to be greater with symptoms such as coughs and sneezes that actually project droplets. Hence the emphasis on physical distancing together with washing hands and covering coughs and sneezes. Aerosol transmission by simply breathing is mainly known to be important in a healthcare setting where there is continuous close contact with infected patients. But aerosol transmission is important enough that religious ceremonies now permitted even in confined spaces in Germany are not permitted to sing. Singing projects larger quantities of virus into a confined space than merely breathing or talking, even though it does so less than coughing or sneezing. The cumulative effect of being confined in the same classroom as an infected child for hours each day over several weeks is simply not known.

The available evidence is quite sufficient to convince everybody who is utterly determined to get kids back to school so that their parents can get back to work. They are all chanting about it in unison. But since they live off other people's work their livelihoods depend on them not understanding.

For example the livelihood of lobbyists for pubs depends on believing that a pub could maintain social distancing of 1.5m between customers if it was permitted to cram them in at 1 per 2 square metre instead of the current limit of 1 per 4. Consequently they can adamantly demand that the number allowed in be doubled so that they might be able to reopen some pubs. It simply does not matter that it would be physically impossible for anybody to get in or out. Their role is to lobby, not to understand things that their livelihood depends on them not understanding.

Rather more evidence should be needed to convince others. Why should one expect to have seen clusters among school children, given that children were withdrawn from schools well before governments shut them? Why would one expect a child to be reported as the first case in a household given that they usually only have mild or no symptoms? I would expect the first case reported to be someone with more severe symptoms who got tested as a result, with any child in the house subsequently found to be infected likely to be recorded as only as a subsequent case assumed to have been infected by the adult.

School childrn will now be spending many hours a day in the same confined classroom space with a cumulative effect on other children and teachers. So it may be possible there could be a gradual but substantial increase in the numbers of infected children before there is enough onwards transmission to more severe cases among teachers and households for this increase to be picked up from surveillance testing and contact tracing.

That could result in a substantial overshoot with the numbers of cases picking up again until it becomes necessary to slam on the brakes again.

The public health officials taking these decisions are not in the same position as politicians mouthing off. They have serious powers, responsibilities and duties, with corresponding legal liabilities for negligence, misconduct or refusal to perform those duties.

I don't see how it would be possible to avoid a second wave from pre-clinical transmission given that the reproduction rate for pre-clinical transmission without physical distancing is itself nearly enough to cause an epidemic. The peak transmission rate for each case tends to occur just before they start to show symptoms so they are only tested after having already had the opportunity to infect others. We are starting from a position with the effective rate already above 1 even before the actual removal of restrictions.

If the decision makers have got it right, that second wave will be smaller than the first wave. They will be able to avoid overwhelming the health system while still substantially raising the numbers of cases and deaths, for some significant increase in the numbers back at work.

If they got it wrong there might be a more sudden increase in infection rates that discredits the "Adapt and Control" policy and forces a serious attempt at "Eradication".

But I don't see much likelihood of that reversal unless they get it so wrong that there is again a serious danger of the health system being overwhelmed. Nor do I see that as likely in Australia. The danger arose from failure to prepare in advance and was averted by the few weeks warning from the collapse in Italy. The next demonstration of spectacular incompetence seems more likely to be about something else rather than acting even slower for a second wave than for the first. It would require criminal misconduct rather than mere negligence and failure to perform duties for the brakes not to be slammed on before a second wave overwhelmed the hospitals. In Australia the consequences are likely to be a longer economic shutdown rather than an overwhelmed hospital system. The same may not be true in many parts of the USA and Europe and it certainly won't be true in most of the countries ruled by kleptocrats.

I don't know whether "Eradication" was likely to succeed. But we did have the option to try and no attempt has been made to find out. Australia still doesn't have any seriouis modelling capability. Other developed countries did not have that option.

If an attempt had been made and had been successful, it could only have resulted in "Zero Tolerance" for outbreaks rather than zero outbreaks. There would have inevitably been occasional outbreaks, but only sporadically with each outbreak or set of outbreaks stamped out rather than becoming a continuous background rate of infection that would continue to grow, again at first gradually and then suddenly. Eradication means preventing that initial gradual growth, not preventing all outbreaks. The resources available for testing and quarantaining contacts and their contacts ("even unto the fourth generation") are sufficient for sporadic outbreaks, but would be quickly overwhelmed when outbreaks become continuous rather than sporadic. Contact tracing is much easier when people have few contacts because they only go out for "essentials". What was achieved by contact tracing under recent restrictions won't still be possible without those restrictions. The last announced numbers for downloads of the "CovidSafe" tracing app would only cover less than 5% of contacts.

"Occasional outbreaks" seems to be what is being sold to people now. The story is that we can have less physical distancing and more people going to work or school together in confined spaces at the cost of some occasional outbreaks that will be kept under control.

That could have been true if we had Eradication first – i.e. zero community transmission for a few weeks before starting to ease up. It might even still be true for Western Australia etc. But it seems pretty implausble for Victoria and NSW now.

It remains to be seen how many people they will be able to get back to work but it seems reasonably certain that any economic recovery will be much slower than if there had been a successful Eradication first.

There doesn't seem much hope of those responsible for this policy doing much to help other countries in a far worse situation, eg our neighbours in Papua New Guinea and Indonesia. They will be far too busy trying to drive people back to work.

For those in the vulnerable categories the danger of infection will now become significantly greater than it was with tighter restrictions and will remain present until a vaccine is developed.

What remains to be seen is how much longer people will remain tolerant of a ruling class whose unfitness to rule is now a matter of life and death.