Tomás Ryan: Is Ireland’s strategy to live with or ‘eliminate’ coronavirus?

Only a conscious decision to implement the necessary measures will lead to its elimination

Where are we now? As we enter the summer months, and restrictions are relaxed, Covid-19 cases have been consistently reduced to low double digits. On June 7th, we had 25 confirmed cases of Covid-19. Just like March 12th. In contrast, in New Zealand, June 8th was the 17th day since their last new Covid-19 case, and prime minister Jacinda Ardern declared elimination of the virus.

What is the difference between June 7th and March 12th in Ireland? In March we were unprepared for what was coming. We did not have guidance or decision-making on the use of face masks. We did not have an adequate infrastructure for Sars-CoV-2 testing and contact tracing. We did not have clear rules and instructions on contact quarantine. We chose not to restrict travel from countries with a high prevalence of the virus.

Today the same shortcomings survive, and the virus survives. The only difference is we are now operating as a society under moderate social distancing, improved hygiene, and caution. But the virus is still here, spreading throughout the community and in clusters. And the result will be the same: a substantial second surge, followed by an effective lockdown.

What’s missing is a clear strategy that takes into account the social, health and economic burdens on the population, and charts a path into a liveable situation. We need to make a choice. Starting from here, we have a second chance to decide what to do, and we have a number of options. But doing nothing is not an option. If we throw our hands in the air and give up, we risk surges of infection that would overwhelm our healthcare system and dramatically increase the Covid-19 mortality rate.


Inevitable second surge

The first choice is continuing as we are until we face, as some Government representatives have admitted, the inevitable second surge, which is happening today in Iran and many parts of the US. If we allow this to happen, whether by conscious choice or by floundering indecision, we will need to respond with a second lockdown to control transmission. Then we would emerge from the second lockdown, again, back at March 12th.

If we maintain this strategy, a cycle of successive lockdowns would need to continue four to seven times until we reach a stage of herd immunity, with at least 60 per cent of the population infected. The health cost of this approach would be about 50,000 deaths. The economic cost and knock-on health effects would be incalculable. Our small and medium-sized enterprises, our healthcare service, our education system and universities, and our quality of life will not survive this approach.

The second choice is to maintain an active suppression of Sars-CoV-2 transmission in the population, with the model example of South Korea. We have already initiated clear suppression through our recent lockdown measures. The problem is we are not maintaining that state of suppression through containment measures. While social distancing can reduce the speed of Sars-CoV-2 transmission, it is the containment measures that prevent seeding and spreading. Containment means the use of face masks and the isolation of particular infected carriers. This requires real-time information of who is infected (through rapid testing) and identification of their close contacts (through contact tracing).

Both testing and tracing work for isolation, which needs to be mandatory and enforced. If we can deliver in maintaining an active suppression strategy, we would gradually accumulate new Covid-19 infections and deaths at a manageable rate over a period of years until we have a vaccine or reach herd immunity. But the virus would not spin out of control and life would continue, albeit with a new reality of mask wearing, social distancing, and limited capacities in workplaces and schools.

Effective elimination

The third choice is the effective elimination of the virus, with no new cases as has been achieved in New Zealand, Taiwan, Greece, Iceland and Norway – and other countries fast approaching this goal. On June 8th an open letter signed by 1,000 citizens, including myself and other members of our scientific and healthcare community, called for both Governments to crush the curve and eliminate Covid-19 from the island.

Achieving this option would mean no further Covid-19 infections or deaths, an open economy, and a return to a fully normal life without restrictions. If we choose to go with the third option, we need to first decide how to initiate this strategy and achieve elimination, and then maintain it. There are two main tactical options for achieving elimination: a sharp lockdown or an aggressive and targeted test/trace/isolate operation in combination with mask wearing and social distancing. Either method will work in theory, and hybrid approaches are possible.

Maintaining elimination would then require us to prevent the seeding of new Sars-CoV-2 infections from abroad. We can do this through mandatory airport testing for passengers travelling from countries where Sars-CoV-2 is prevalent, as practised in Austria, Japan, South Korea and Hong Kong.

Whatever choice we make, neither suppression nor elimination can be maintained without an effective test/trace/isolation infrastructure. Even though we are currently operating at only 20 per cent of our existing testing capacity, the system is too slow and unreliable to sufficiently identify and isolate contacts before presymptomatic and asymptomatic spread of the virus. It needs to be reorganised from start to finish so that we can isolate close contacts 72 hours after primary cases display symptoms. We cannot wish the virus away, but we can have a conversation about how we choose to face this reality.

Tomás Ryan is associate professor in the School of Biochemistry and Immunology at Trinity College Dublin and chairman of the European FENS-Kavli Network of Excellence.