Wednesday, April 8, 2020

Ending Corona Lockdowns





Spread of Corona Virus as of 7 April

While it is still early, we need to think ahead about ways to end lockdowns assuming we cannot totally eradicate the disease.

Remember there is no vaccine against AIDS and it has been with us for about 40 years. We cannot be sure that we will have a safe reliable vaccine for Covid 19 in 12 or 18 months. We cannot stay in lockdown for years. Lockdown will likely start to break down after 3 to 6 months for a variety of reasons, social, economic and psychological.

But there is a strategy for getting out of lockdown and self isolation with minimum deaths based on mortality rates by age group. 

Based on Australian data:
No deaths out of 1600 cases in the 20–29 age group
No deaths out of 830 cases in the 30–39 age group
No deaths out of 700 cases in the 40–49 age group
1 death out of 820 cases in the 50 to 59 age group

Australian Government modelling released 7 April shows very low hospitalisation and intensive care rates for people under 50, particularly for those under 30 (based on analysis of over 5000 cases)

I have not examined the younger age groups as the case numbers are too low to have much confidence in extrapolating the results from them at this time, but that is perhaps a great indicator of low transmission rates to young people or lack of health problems among them when infected such that few are being tested.

From those mortality numbers above we can see that the risk of death in these age groups is virtually zero provided the very sick of those infected have access to treatment including ventilators and provided that they have no other chronic illness when infected.

So we can gradually release all very healthy people in these age groups from lockdown and expect a death rate not much worse than seasonal flu provided the health system is not overwhelmed, but it will be a lottery as to who will die.

Over the course of the next say 2 months we would continue to build out hospital beds, ICU beds, PPE, ventilators and building our knowledge of what drugs help recovery and be that much closer to a possible vaccine and as current cases run off as a result of the lockdown medical staff and ffirst response staff could take breaks.

The sensible place to start release from lockdown is with all the very healthy 20-29’s who do not live with any over 50’s or people with chronic illness and release them all gradually over the course of 1 month. They should all be able to carry proof of age such as driver’s licence, official ID card or passport.

No one would have to leave isolation and healthy people eligible for release from isolation but living with very young, elderly or sick people would be encouraged to maintain the isolation of those people.

As release from isolation commenced bars, restaurants and shops staffed by this group could open with some protection for staff eg screens around service areas. Gradually members of this group would become infected. We know about 85–90% would need no treatment at all, maybe 10% would be hospitalised and 5% would need intensive care, but they would not all get sick at once so hospitals, intensive care, staff, PPE and ventilators would not be an issue.

As people recovered they would become immune and could then assist in relieving some medical staff and nursing home staff and take higher exposure jobs such as serving customers, particularly if we then have proper reliable antibody tests. This would also be the start of building herd immunity.

Depending on hospital, ICU and ventilator unused capacity, we would then begin to release the very healthy 30 to 39 year olds at a pace calculated not to overwhelm the medical system. More businesses would reopen or increase activity as more staff and customers became available. Herd immunity would continue to build. Economic cost of lockdowns would start to reduce, residential rents could start to be paid and slowly so would commercial rents.

Over a period of about 4 months most of the workforce will have been released from lockdown and herd immunity will be continuing to build. At no time would hospitals, ICUs or ventilators have been overwhelmed.

During the 4 months, we would expect to also have data as to releasing the 15–20’s. There is no reason to suspect that this group would not be able to be released subject to hospital/icu/ventilator/numbers.

In Australia we have had 5 deaths out of 900 cases for 60–69 age group.

At this stage (about 6 months) it may be that there could be release of over 60’s (again on a voluntary basis and with full explanation of the risks and with people with chronic illness such as hypertension, diabetes or coronary disease or other illnesses not leaving isolation). People would weigh up the risks for themselves after getting a personal medical briefing.

By 9 months about 60 to 80% of the population would have been infected. There would have been some deaths, some totally unpredictable and unlikely. Herd immunity would be at a stage where it reduced the chances of catching the disease and would be reducing loads on medical resources.

After this 9 month process, the over 70s and those with chronic disease would perhaps face difficult decisions, but they would have the benefit of reasonable herd immunity if they chose to leave isolation. They would also have the benefit of well developed treatment protocols and informal trials of many differing treatment regimes. It may be that infection isolated communities would be developed for such people so that they lived freely within a highly protected community.

There are some practical difficulties with this approach, but every approach has difficulties. Some people will cheat, but so long as they don't end the self isolation of someone else and there are not too many cheats it won't really matter. The main issue is for older people who spend more time in lockdown and feel they are denied economic opportunity. This could be eased by increasing the safety net payments as time goes on from the savings of less people being eligible or needing the safety net.

The issues of how long immunity lasts may still be with us in 12 months time but by then we may be within mere months of a vaccine. Time alone will tell.


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