COMMENT

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24 June 2020

Easter Monday proved to be more or less the time of peak consequences of the disease in Britain.

Science has not necessarily been definitive since but knowledge about the disease amongst doctors has improved markedly since and they have a body of practical experience to draw on.

A reduction in the percentage of ill patients being placed on ventilators is one development. Steps to reduce blood clotting early appears to be another and the appearance of the steroid dexamethasone as a treatment to reduce mortality is another.

In the event of Covid-19 getting a second wind what might be the shorthand steady state steps used to control it?

Allow people to rearrange their lives and travel as they think fit but insist on one metre separation and not meeting more than three people in one day outside a bubble except where the person's job requires it. Fine tune the bubble principle into multiple different permutations.

This would maintain liberty and individual judgement and reduce transmission of the disease whilst stopping short of lockdown.

It could allow months or years of coexistence with the disease.

24 August 2020

The hypothesis that most of the Covid-19 transmission has been by aerosol needs urgent further examination.

It would partially account for why cruise ships which kept a modicum of good social distancing became heavily infected.

Likewise big naval ships, hospitals and nursing and care homes.

Lockdown would have largely prevented it as would a move to conducting activity outdoors but those cases could not have offered that opportunity even with good infection control.

The first thing I was ever taught about hospital design was that the Victorian Nightingale wards had large windows and very copious opportunity for cross-ventilation to reduce infection even though they usually could contain many patients.

The second was seeing photographs of patients with their beds outdoors in the sun at sanatoria, especially for the treatment of tuberculosis. These photographs typically dated from before and after the first war.

The model of well-lit and well-ventilated wards, by natural means, persisted for about a century.

One direction, mechanically assisted airflow is likely to be the predominant model now.

The filters in current generation airliners would probably catch the aerosol but the airflow is still front to back with a proportion of the air recirculated.

The filters in air-conditioned commercial buildings would be less likely to do so even if they were changed sufficiently often, which is less probable, and air is frequently recirculated.

Building management, at the engineering and architectural level, has long been aware of aerosol risks as the possibility of Legionnaire's Disease has been a nightmare for decades.

It is inconceivable that the U.K. government's advisory committees have not received some relevant engineering advice but their composition probably does not reflect it.

Further studies into aerosol transmission are necessary to map the way forward.

29 August 2020

This must necessarily be hypothetical at this stage if aerosol is the primary means of transmission:

The nature of the spread of infection will be different from that of Legionnaire's Disease where, for example, its presence in the air conditioning of the BBC's Broadcasting House in central London lead to outbreaks in buildings nearby. The natural home of this virus is not in aquatic environments and its viability outside a living host is of relatively short duration.

Outdoor air is likely to be a significant block to transmission as too few infectious particles will reach another person to, in most cases, provide the infectious load to initiate illness.

Similarly, the low doses transmitted by non-prolonged use of shared public transport may be insufficient to trigger much illness.

Prolonged or repeated exposure on transport would raise risk.

Breaches of social distancing rules outside, whilst not desirable at all, might trigger even less.

It would matter a great deal though inside - how crowded with 'non-bubble' people, how long and how frequent the potential exposure.

To take the infamous (but unproved) example of possible transmission at a horseracing meeting, travelling to the meeting, watching the horses outdoors and socialising outdoors would be relatively low risk but spending time in a racecourse's indoor bars, or in pubs afterwards, especially if prolonged, would push up the risk substantially.

Working in an abattoir where there is a lot of water aerosol on which the virus could take a short distance indoor lift would be high risk.

Working in a hospital the infectious load could be high, prolonged and frequently encountered. Holding a staff briefing in an open courtyard of the same hospital might rate as low risk in contrast. Good protective equipment should be a watchword going into the autumn.

Nursing and care homes could have similar considerations, including airflow.

Those the residents meet on frequent, prolonged basis indoors would pose the greatest potential risk to them not those they meet infrequently outdoors.

This hypothesis reduces the risk rating of proximity, and of travel, relative to other risks.

It increases the measures that need to be taken in shared, well-populated, indoor spaces, frequented by people from multiple households, like workplaces, if they are poorly ventilated going into the coming seasons of inclement weather.

Quarantine policy would have little part to play in the event of this hypothesis being correct, until vaccines were widely used.

At the current stage of the pandemic nearly all countries will have some incidence of disease, possibly more that is asymptomatic than symptomatic.

Travellers are being tested more so more cases show amongst them but if, say, 20% of a population has travelled internationally since the start of the pandemic it is likely that the incidence of the disease has been no more prevalent in them and their first degree contacts than in those of the population that have not travelled internationally.

The means to control aerosol borne Covid-19 would rest almost entirely domestically.

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SOCIAL DISTANCING


Reviewed by ANDRE BEAUMONT


Britain must face certain realities.


It is Easter Monday 2020 and we may not have reached the worst for Covid-19.

In economic terms this quarter must be written down if not quite written off. Planning for recovery should be for the next one and beyond. This one must concentrate on minimising deaths.

There is no point in announcing Britain open for business if it then becomes a pariah as a reservoir of infection.

China has largely coralled Covid-19 but no one is seeking to travel there even if the borders were open. Desirable business that can be done remotely will be but it would still be surprising if it had the same output this quarter as it had in the same quarter last year.

Australia is getting its Covid-19 outbreaks under control and as an island we should look to it for example.

Full social distancing in Britain should be kept in place for a further six weeks at a minimum. This is because it cannot reach the comprehensiveness of testing of cases that Australia and South Korea are getting to. This is about geography in the first comparison and about culture in the second.

What it can do is set up hotlines in advance of relaxing social distancing so that those who get symptoms can give lists of their recent contacts. This, however, would have to be accompanied by a certain type of social distancing relaxation and still be voluntary as people may have reservations about listing contacts. At the minimum, though, those mapping clusters of Covid-19 would be alerted with lower latency.

The type of relaxation is outlined below.

Particular age groups should not be prioritised. Asymptomatic cases are a real problem in the spreading of the disease and those at most risk are those least likely to be asymptomatic and involved in spreading the disease in its tail off phases.

Children might be allowed to return to school after the time already scheduled for summer half term, not before, to allow for a supervised revision period and (non-national) examinations, both of which could be instituted with degrees of social separation.

Open plan office working should ideally not be permitted, in my opinion (as an architect). Certain places have very poor fresh air circulation in terms of complete air changes - aeroplanes, open plan offices including those that have air-conditioning, and the inside spaces of bars and restaurants. People could, however, be permitted to return to offices on a rota basis to keep densities low and to office spaces that used individual rooms and to laboratories with low density occupation.

It is fast approaching summer and restaurants and bars might be allowed to reopen using outdoor spaces and spilling out a little onto pavements as on the Continent but keeping indoor spaces shut except for the use of washrooms, cloakrooms and the like.

Travel restrictions could be relaxed but on the basis that you only meet one person at a time at your destination.

This could also apply to workplaces, restaurants and bars and would be why you would be able to give a list of your contacts on a hotline - if you meet one person at a time it is safer in terms of reducing transmission and you can also remember who you met more easily.

Some categories of economic activity look lost for this quarter - all forms of entertainment in public, for example.

There are many other cases of activity, economic and otherwise, where the government will need all of a month or more to decide and plan - what happens to university students, for example. You are not going to send final year medical students back into the examination hall when they are better suited to their vocation in hospitals.

Spain, which still has too high a casualty rate for comfort, is to undertake some relaxation but mainly in directions Britain already permits - allowing construction and manufacturing, areas of activity where good procedures can ensure you need only meet one person at a time close up or not at all.

In a nutshell, if medical opinion is not strongly against, in June or beyond, the two metre distance rule could be replaced by a one person at a time rule.