COVID-19: Why testing and tehcnology might be an exit strategy

The BBC reported that:

There are essentially three ways out of this mess.

• vaccination
• enough people develop immunity through infection
• or permanently change our behaviour/society

But a vaccination is reported to be around 12-18 months away (and could be much longer), and it is estimated it will take two years for herd immunity to arrive. Both seem like a long way into the future, and based a relatively short (and probably quite soft) experience of social distancing - that seems like a massive burden on individuals, the economy and ultimately society. Is there any way out of this?

In order to see if there might be more welcome paths through this lets start by testing the constraints on the assumptions above.

12-18 months for the development of a vaccine would be unprecedented (it usually takes a decade or so, and is expected to take almost 50 years for a HIV vaccine) but the real problem seems to be the testing:

“We could have a vaccine in three weeks, but we can’t guarantee its safety or efficacy,” says Gary Kobinger, a virologist at Laval University in Canada” New scientist

OK, so perhaps we might be able to get a vaccine more quickly if we were less worried about whether it worked and had harmful effects. As a 40-something-year-old without any pre-existing conditions I’m likely to hold out for the gold standard in vaccine testing before I considered it, but I suspect an 85 year old with asthma might feel differently (especially if their quality of life is already greatly diminished by self isolation). Perhaps it would would be possible for those at the very greatest risk to accept more risk with a future vaccine, allowing them earlier access to it.

Now, let’s look at the herd immunity numbers. There are 66 million people in the UK and I have seen estimates of between 60% and 80% required to develop herd immunity. Around 1% of patents seems to require a ventilator and they typically require them for a few days to a few weeks. If we assume a week on average and 70% required for herd immunity then we would need 66M * 70% * 1% = 462000 respirator weeks. As the UK has 8175 respirators at the moment it would take 56 weeks to accommodate that even if every respirator wasn’t needed for anything else, and the government could throttle social distancing sufficiently well to hold on peak demand. Hardly conclusive, but if we assume that the UK could double its number of ventilators and that most of the remainder will be used for non COVID-19 patients then perhaps this validates estimates in the 1-2 year period.

Obviously the good news with herd immunity is that half way through this period, ~35% of the population will be immune as they have recovered from the virus (assuming it doesn’t mutate and reinfect them). At this stage those individuals could be leading normal lives, safe in the knowledge they won’t become infected or infect others.

This is where we turn to the practicalities of social distancing and self isolation. At the moment anyone who has the symptoms of COVID-19 (which are not specific to this virus) are expected to stay at home for 7 to 14 days. This unfortunately means many people who do not have COVID-19 will be self-isolating unnecessarily.

Conversely many (perhaps between 18% and 31%) people will never show symptoms and as such will not self isolate. More might choose not to because the benefits are for others, whilst the cost (of isolation itself and of lost earnings, etc) is borne by them.

If only we could reduce the number of people who didn’t need to self-isolate and increase those who did. Fortunately that might be easier than it seems.

• A growing number of people will have already been infected and should no longer need to self-isolate. If we could test for those who are immune at scale, then we could lower the burden of unnecessary self-isolation. Fortunately the UK is already starting to purchase such tests.
• There are emerging 15-minute home tests which could be used to allow people who self-isolate to take themselves more quickly out of isolation if they test negative (perhaps for two days running)
• Singapore has proved that it is possible to limit infections whilst not overly reducing citizens freedoms (e.g. pubs and schools are still open). They have done this through quick and rigorous contact chaining of infected individuals - which is labour intensive and as a UK research paper points out “For contact tracing to be an effective public health measure requires secondary cases to be discovered before they become infectious; hence the time from the primary case becoming infectious to the tracing of their contacts needs to be shorter than the incubation period.”.

Putting these together we can see that if we were certain about whether people who had symptoms were or were not infected we could either release them from self-isolation more quickly, or we could start looking for the people who they had infected more quickly to ask them to self-isolate too. Of course doing this manually is no longer feasible, but this is something technology can solve, as Singapore have done with their app TraceTogether.

How would this work? If you have any symptoms and self-isolate you let the app know. You are immediately sent a home testing kit, and if you test negative you can leave self-isolation (this is a strong incentive to have the app, even in a country where we value our freedoms). If you test positive all your contacts identified by the app are ordered to self-isolate. The good news is that many will only need to self-isolate for 24h and the rest will get early warning of what they have, and perhaps proactive treatment if the antivirals prove their worth. Because people are only self-isolating for a short while they are more likely to comply, and because they get testing (free from the government) and proactive treatment they are happy to have the app. We collectively manage to contain the spread more effectively, whilst getting more people to work and enjoying life.

Sure life wouldn’t be back to normal, but we could make social distancing and self-isolation more effective and less costly through effective testing and technology. People could tolerate this for longer (perhaps indefinitely) and the government would get better data to make better decisions. As infection rates went down we could either try and go for broke and eliminate the virus from our shores, or we could relax social distancing to speed to herd immunity whilst knowing exactly when we have to reintroduce more stringent measures,

My prediction is that without this technology that the self-control (and even police enforced control) required for one to two years before herd immunity or a vaccine arrives will be too tough, and we’ll end up with uncontrolled spikes. If on the other hand we get smart with testing and technology we can reduce the impact of social distancing and self-isolation whilst getting herd immunity in a managed way, and hopefully protecting the most vulnerable through an early vaccine that might be too risky for the young and healthy.