The new coronavirus, SARS-CoV-2, is the ultimate escape artist, a tenacious adversary that is proving very challenging to suppress.
When Singapore entered lockdown on April 8 it was troublesome news. Until then it was one of the few countries that was successful in bringing initial outbreaks under control without resorting to mass quarantine. This underlines how easily the virus can return. Singapore had been containing cases through rigorous testing and tracing with a strict but limited quarantine. Those without symptoms but who had contact with a confirmed case were ordered into strict isolation. They were also required to confirm that they were doing so by sharing their location data.
Italy entered national lockdown on March 9. Twelve days later peak daily increase in cases was reached and there has been a very slow tapering since. Over four weeks after entering lockdown daily new cases are still double what they were on March 9. IT is now facing many more weeks of social disruption. The Italian government has not been able to financially support its citizens to the same extent as the Irish government has. Tensions are building across the poorest southern regions as people run out of food and money.
While Irish authorities have worked well to introduce income supports, many businesses here are still struggling. Some are beginning to wonder at what point the cure could be worse than the disease.
Last month, after relaxing mass quarantine in many areas, China noticed that the majority of new cases were from those entering the country. It is now enforcing a temporary suspension of entry by foreign nationals holding Chinese visas or residents’ permits. The Chinese city of Wuhan ended its 76-day lockdown last week, allowing residents to travel in and out of the city without special authorisation that had been given through a mandatory smartphone app. Though some restrictions still remain it must be a joyous feeling for residents under severe restrictions for so long.
In Europe, the leaders of Norway, Denmark, the Czech Republic and Austria have announced plans to relax lockdown restrictions. As with China, we await the outcome in hope and anticipation.
A recent paper from the UK-based Imperial College Covid-19 response team described two fundamental strategies to manage an outbreak: suppression and mitigation.
With suppression, the aim is to reduce case numbers to low levels or eliminate them completely. The main challenge of this approach is that measures need to be maintained, at least intermittently, for as long as the virus is circulating in the human population, or until an effective vaccine becomes available. This has been Ireland’s stated strategy but our country has been slow to reach the requirement needed for a complete suppression.
We have so far fallen short of South Korean standards of testing and contact tracing and we have been unable to enforce Chinese-style mass quarantine. Professor Sam McConkey, the head of the department of international health and tropical medicine at the Royal College of Surgeons, has encouraged stricter measures in order that we more quickly re-emerge from lockdown.
As we are an island nation, he asked if we should follow the example of New Zealand and aim to eliminate the coronavirus through 60 days of contact-tracing and self-isolating, the use of GPS location data, a 14 day quarantine for travellers, cloth reusable masks for all and a phone app to show a person‘s status. This would have to be done in partnership with Northern Ireland.
In mitigation, the aim is to use interventions such as social distancing, not to interrupt transmission completely, but to reduce the impact of an epidemic on the health services. In this scenario, “herd immunity“ builds up through the epidemic. Once 70 to 80 per cent have been infected and convalesced, the risk of further outbreaks becomes low. The risk with this strategy is that it may easily become uncontrollable resulting in a hugely overloaded hospital system, mass suffering and loss of life. Initially the UK‘s ’s stated strategy was mitigation, but the authorities soon realised their folly and switched to attempting suppression. The UK is on course to be one of the worst affected regions in Europe.
In his recent medium.com article, Coronavirus: The Hammer and the Dance, Tomas Pueyo, an engineer and businessman, expanded on the suppression strategy and mapped out a vision for the next year to 18 months.
He outlined the initial importance of “the hammer” or lockdown restrictions and said it should take between 3 to 7 weeks depending on how strict the measures were. The quicker a country can get the R number below 1, the faster it can re-open for business. The R or reproduction number is a term used to express how contagious an infection is.
The R number of the Influenza virus, for example, is 1.3. That means that if someone gets the flu, they will pass it on, on average, to 1.3 other people. Initially, the average R number of SARS-CoV-2 was 3.28, which means that each person who contracted it passed it on to approximately 3.28 other people. However, the R number is not fixed and can be affected by human behaviour, such as social distancing.
To control the spread of COVID-19 we must get the R number to drop below 1. In Hubei, “they went all the way to 0.32”, Pueyo said, before adding that we may not need that: “perhaps just 0.5 or 0.6”.
Once a country attempts to get back to normal, “the dance” period begins. There is a strong possibility that the coronavirus will re-emerge from time to time. One imported new case could spread to many, so governments may need to reintroduce intermittent, graded social distancing and partial lockdown measures.
To enact this efficiently and with as little disruption as possible we must study and record the effect of all the various measures on the R number. We must also do a cost-benefit analysis of each to establish the best balance of reducing the R number with the least harm to the economy. This information could be published and a clear plan outlined.
Our health authorities and government have done such important and commendable work in delaying the spread of Covid-19. Though, unfortunately, 287 people have lost their lives, many of our hospitals still await the surge. However, conversely to the European countries planning to relax restrictions, both Ireland’s daily new cases and deaths have not peaked.
Our authorities need to make Ireland’s strategy clear. Are we aiming for complete or partial suppression followed by a longer term “dance”.
If it‘s the former we need much stricter measures in the short term, including border closures. Currently this strategy appears unachievable in Ireland. Some have waited two weeks or more for a test result compared to 24 hours in South Korea or 48 hours in New Zealand. We would also need a joint strategy with Northern Ireland to ensure restricted immigration. If it‘s the latter we need a clear plan to reach herd immunity in a controlled way.
Whichever one we go for in the end, the stricter the initial mass quarantine and the more rigorous the testing and contact tracing, the quicker a society can return to normal.
Dr Domhnall Heron is a pharmacist and GP registrar