There is no covid-19 lockdown exit strategey

I have been discussing long term outcomes of the covid-19 outbreak since the UK had just a few dozen cases. It's clear that similar discussions, within the scientific and political community, have not borne fruit. On the BBC's Andrew Marr show today, advisor the UK government, Neil Fergusson, said the UK does not have an exit strategy, but hopefully will within the next week or two. South Korea, widely hailed as one of the countries that successfully dealt with the virus is also struggling with exactly the same question and has not yet reached any conclusions. In fact, as cases drop, South Korea is considering tightening restrictions. As far as I can see at this point, there is only one country in the world with an exit strategy - Sweden.

There are exactly three outcomes to this pandemic

We discover a vaccine or effective treatment, immunise/treat people so they become medically immune and the problem goes away.
Eventually so many people catch the disease and become naturally immune that the problem goes away.
We do not discover a vaccine or treatment and we find that after infection, immunity only lasts a finite amount of time and the virus becomes endemic (meaning it is around forever). The problem never goes away completely.

The medical immunity and natural immunity outcomes sound better than the endemic outcome because the problem goes away, but the social cost of getting to that point is high. There is also the chance that they don't happen, despite our best efforts. None of these outcomes are palatable and we do not yet have the information to decide which is the most likely.

You will notice that none of the options listed above are reduce numbers then track and trace to eradicate the virus. That option is long gone. Even if developed countries, with their strong health and social care systems, could do this, the disease is running wild through the developing world. If we eradicate covid-19 in the UK, we would just get wave after wave of reinfection until one of those three options above occurred.

So if there are only three outcomes there are probably only a handful of ways we get there. In this post I thought I'd explore the options that I could think of. First a note on the vulnerable. The strategies below refer to the things that the majority of the population would do - I would expect extra measures for vulnerable people. However, it is of note that, the faster we deal with this, the faster vulnerable people can be free of restrictive isolation. We should ask ourselves how humane it is to ask a vulnerable person to live in near-perpetual isolation for their own good. So here are the options as I see them

Stay in lockdown until we have a vaccine or effective treatment

This is the far extreme option and in theory the option that will absolutely minimise deaths from covid-19. The worldwide eradication by isolation option was already a non-option by the time the UK had its first confirmed internal transmission. By that time, covid-19 was clearly a pandemic and would be impossible to defeat worldwide by isolation. But I wonder if some of that sentiment still persists into a desire to keep us in semi-permanent locked down until we have a vaccine.

I'm a scientist, but not a virologist. So, I cannot provide an expert commentary on the status of vaccine development. The media repeatedly say "at least a year" for a vaccine. Something I do know very well is that scientists are optimists, so, if they say a year, it is likely to be two. Something that is rarely discussed in the media is that we have never been able to develop and administer a vaccine for any of the 5 endemic and mild coronaviruses which cause common cold, nor the deadly SARS and MERS coronaviruses. There is no guarantee we will discover a vaccine for covid-19. We could find ourselves after two years of lockdown with scientists still saying a vaccine is about a year or two away.

Treatment may be a more likely option. Scientists are already using supercomputers to tap into databases of existing drugs, and see if there are any molecular structures in them that may disable covid-19. We have come on leaps and bounds in recent years with antiviral drugs. HIV treatment is and example. It used to be that this disease was a death sentence for an infected person and any of their sexual partners. Eventually we developed drugs which reduced the ability of the virus to harm, meaning people with HIV could live a full life, and recently a drug that reduces transmission was licenced for use in the UK. Maybe we can find something like this to turn covid-19 from a killer to a manageable disease. But again, expect such developments to be at least a year or two away.

I will again flag the need to be humane. Is it fair or right to keep people in lockdown or keep children out of school for years of their life? This is a direct conflict between preserving life, vs maximising quality of life. I am certain that there are as many opinions on this as there are people who read this post.

Repeated lockdowns until either a vaccine/treatment is discovered or we have natural herd immunity

This was the UK government strategy when it initiated the lockdown. The chief scientific advisor suggested that we could expect to spend six of the next twelve months in lockdown. Looking at how this cycle in going, we started with a few confirmed cases around late February to early March and I am going to take a guess that by the time cases drop off and lockdown is released it will be late April to early May, the NHS will have not quite been overwhelmed and there will have been a few million people infected. So in a two month duration "first wave", we will have spent at least half of this in lockdown and maybe 4-10% of the population will have recovered from the disease and will hopefully be immune. We can then release lockdown for maybe a month and repeat the cycle.

If we do this, then I think we should expect these cycles to continue for between one and four year. Why so long? Well if we only hit 4% of the population with the disease and we need 60% of the population to be immune to get herd immunity, then that is 15 cycles. But herd immunity is not an on/off switch. As more people become immune it will take longer for the disease to spread, so successive cycles may take longer or might involve fewer people catching the disease, but they might only involve being in lockdown for one month in three or four. Of course, if we develop a vaccine or treatment in the meantime, then we can make use of that and end the lockdowns.

But again. the question remains, is it fair or humane to repeatedly lockdown the country for this length of time? I'm not going to try to answer this question, I just want you, the reader, to know that this is what may be needed and come to your own judgements.

Release lockdown once covid-19 is eradicated in your country, then close the borders until it is safe.

We need permanent or repeated lockdowns until we have medical or natural immunity, because, even if one country eradicates the disease rapidly, vast swathes of the world will not. So regular reinfection will be likely from country-to-country movement. One option to avoid this, would be to simply pull up the drawbridge and close the borders. If we get any pockets of infection springing back up, then we track and trace them and isolate potentially infected people. Once the world situation is safe, we reopen our borders.

The difficulty may be in how we decide it is safe. If a vaccine or treatment is discovered then the problem is over. But what if this doesn't happen. It is likely that many developing countries will not be able to put adequate controls in place to eradicate the disease by lockdown. But even in these places, natural herd immunity may kick in eventually and the disease will disappear. This is essentially what happened with Spanish flu. However, it could be years before it is considered safe. Also, as a country, we would have little to no natural immunity, making us potentially susceptible to new outbreaks. You may also feel that there is a moral dilemma here. In this globally connected world we would basically saying to developing countries, we're fine, you're on your own, and please hurry up and let the virus come to a natural end (with many deaths) so that we can get back to normal.

Allow the medical system to be overrun to rapidly generate natural herd immunity

This is the opposite end of the scale to staying in perpetual lockdown. Unfortunately it is the only strategy available to many developing countries. If two-thirds of your population live in slums, then no amount of lockdown is likely to help. the disease will spread and if your healthcare system cannot cope, then there is little that can be done.

Would a developed country allow this to occur? Sweden is currently one of the few countries not enforcing lockdown to deal with its cases, instead it has limited social distancing measures in place. This was the strategy that the UK government initially took, before changing to tighter lockdowns. Sweden has fewer intensive care beds per head of population than the UK, so may be considered less prepared. But perhaps, as a country, they are not willing to sacrifice freedom while they hope for a vaccine, or perhaps they are better at this moderate social distancing that the UK was. The lower population density and the smaller size of Sweden's large cities might help them cope. Time will tell if they will maintain their current stance and if it was the correct one.

Boost medical system capacity to a level where we can deal with a very large number of cases then allow people to catch the disease and gain natural herd immunity

As a variation on the previous strategy, if we can boost medical system capacity, then it becomes safer to allow the disease to spread. If, and only if, a medical system is not overwhelmed, Covid-19 has a mortality rate of around 1-2%, with most of these deaths being people with underlying health conditions. UK advisors estimate that, within a year, half to two thirds of these deaths would have happened anyway. If, however, we run out of ventilators to treat patients, the death rate jumps to 5-10%.

If we had more capacity in the health system, then we would be able to allow the disease to spread further without the jump in mortality. Many countries are setting up dedicated field hospitals such as the Nightingale hospitals in the UK. In the UK we have increased the number of respirators from 8000 to 12,000 since the outbreak began and we are aiming to have 18,000-20,000 soon. With enough ventilators, a country may be able to follow the Swedish approach and cope without getting the jump in mortality. More respirators may permit bigger gaps between lockdowns in a multiple lockdown strategy, which would also mean fewer lockdowns were needed.

The no immunity scenario

There is an underlying assumption in all of these strategies. This is that eventually we will become immune or the disease will become nothing more than a nuisance. This may be because a vaccine is produced, or a drug treatment is developed or because by catching the disease and recovering we become immune.

None of these three things are certain. Covid-19 is a coronavirus, but there are seven other coronaviruses that are known to infect humans. Five are mild and are some of the causes of the common cold, the other two (MERS and SARS) are potentially deadly. To date, no vaccine or effective drug treatment has been developed and administered for any coronavirus! In addition, for the five mild coronaviruses, immunity after infection is not permanent. If you catch one during this cold season, you can catch it again next cold season.

What does this mean for the covid-19 outbreak? It means that there is a significant chance that the disease will become endemic. This could mean that there is a fresh outbreak of covid-19 every winter, just like happens with influenza (flu) and other common cold viruses. If this is the case then pretty much everything we have been doing with lockdowns will be in vain. However, all is not lost. As viruses become endemic, they tend to become less severe. This is because viruses are mutating all the time, and a strain which is less deadly, tends to be able to spread further than one which is more deadly. Hence, the milder strains of the disease tend to outcompete the more severe strains. So, even if winter becomes "covid season" it may be that by this time, covid-19 has become no worse than the flu that we see every year.

Conclusion

These were all the exit strategies I could think of. The painful part is that there is no good option. Whichever strategy is a compromise between economic and social pain, illness and death. By the end, it is perfectly possible to find that the wrong choice was made because right now, we cannot know what is ahead for natural immunity, immunisation or treatment. I imagine the UK will go one of two ways. It will either boost medical system capacity and have multiple lockdowns, each successively less severe than the previous. Alternatively it will implement track and trace after this lockdown and it will close the borders, perhaps with quarantine measures to allow some travel. Eventually the hope will be that natural immunity, a vaccine or effective treatment will provide a way to end the outbreak and the restrictions, but as described above, this is not a given and eventually we might just have to accept that covid-19 is endemic.

So what do you think? Are there any options you think I missed? What do you think is the best option or the option that will get used? Let me know in the comments below.