Covid-19 risks from international travel remain dangerously high
The pandemic is accelerating, and we are vulnerable to a new seeding of virus from travel
‘It’s not enough to consider the Covid-19 cases in a given country – we must also pay attention to the number of visitors we receive from that country.’ Photograph: Kate Geraghty
Yesterday, I had a heated debate with a close family member on the subject of international travel restrictions. She insisted that the priority must be to get our airports and ports fully open for the remainder of the summer season.
I asked why this was more important than first ensuring that we can maintain the suppression of Covid-19, so that the economy can remain functional and schools can safely open in September. She retorted that it was more important to go on holiday to a hot country – and besides “school is boring!” To be fair, she’s a six-year-old child.
On June 30th we had 11 new confirmed cases of Covid-19 in Ireland – huge progress from our worst day of April 10th, where we had 1,169 new cases. But on April 10th there was only 86,409 new Covid-19 cases worldwide, while on June 30th there was 159,962. The pandemic is accelerating, and Ireland is vulnerable to new seeding of SARS-CoV-2 from foreign travel. Other countries, such as Portugal, are suffering the effects of not sufficiently restricting their incoming travel.
We cannot and should not stop or prevent travel indefinitely. But right now, the risk-to-gain ratio for foreign travel is dangerously high. It is a welcome development that the European Union have drawn up a “green list” of 15 countries that can have open borders with EU member states. Members of this list have Covid-19 cases over the last 14 days close to or below the EU average per capita. But without travel quarantine, this list may not be sufficient to protect Ireland’s interests at this time.
Numbers of visitors
It’s not enough to consider the Covid-19 cases in a given country – we must also pay attention to the number of visitors we receive from that country. In Ireland, we get a total of about 10 million visitors per year (10,807,500 in the year 2019). Of these visitors, 2.4 million came from North America, while 3.8 million came from Great Britain. In other words, over 60 per cent of our visitors come from countries that have far greater Covid-19 prevalence than us. The relative size of the destination country also matters. Germany receives about 5.5 million visitors from the UK every year, but has a population of 83 million that dilutes the relative effect.
Right now, there are about 30,000 new confirmed cases of Covid-19 being reported per day in the US. Given the known case/fatality rate, we can estimate that up to 0.5 per cent of the US population have active SARS-CoV-2 infections (including asymptomatic case). Based on normal summer traffic of 9,500 visitors from North America per day in July/August, we would expect to import 47 new active infections per day from the US alone. From Britain, based on current Covid-19 prevalence and normal travel levels it could be as many as 20 active infections per day. Plus there would be infections from other EU and non-EU countries. Without travel quarantine, all of these cases will enter the population and spread the virus. Over the past two weeks, Ireland has had less than 200 confirmed new cases of Covid-19 in the community. Imagine adding another 1,000 cases from abroad in the same period of time. For now, the two week quarantine period is important.
On top of this, Irish residents embark on about 9 million foreign trips per year (8,814,400 in 2019, with 2 million of these in July and August). Depending on the destination, there is a risk of returning with the virus. It seems plausible that risks associated with air travel itself (and the use of airports) can be minimized. But the problem is not so much transit, as the travel between countries and the choice of destination. Some destinations carry much higher risk, such as Sweden, Portugal, and Britain. Some countries, such as Austria and Denmark, may be roughly on par with Ireland. Others seem to have consistently less Covid-19 cases, such as Finland, Iceland, and Greece. But of course, there’s a world of difference between spending a week in holiday cottage in rural Finland, and congregating with tourists from multiple nationalities at busy resorts in Greece or Spain.
People want balance. But right now, we simply do not have the containment measures in place to prevent the seeding of new SARS-CoV-2 infections from abroad turning into super-spreader events. How do we manage this situation? The thing we need most is time. Time to develop a green list of countries that works best for Ireland. Time for our neighbours on both sides to get their own situations under control. Time to get our act together on mask usage. Time to build a fast and reliable test/trace/isolate operation – including testing at ports and airports to reduce quarantine requirements. Time to discuss an all-Ireland strategy for managing Covid-19.
On the subject of travel, communication has not been great. But we have a new government, and they also need some time to get on their feet and deliver their message. Currently, we do not have a sustainable Covid-19 suppression strategy or infrastructure. The summer months are our opportunity to build it, so that we can prevent future surges and consequent lockdowns. And, we still have the opportunity to achieve a zero-Covid Island, which would vastly improve our quality of life and our economy. Domestic tourism will be necessary to compensate for lack overseas visitors to Ireland. It is the airlines of course that remain heavily exposed, and state interventions may be necessary to support them.
In the mean time, special interest groups would be best advised to use their resources and influence to ensure that a comprehensive test/trace/isolate infrastructure is a top priority for government. And as citizens, we need to decide whether we want to be adults about this, and ask whether a summer holiday abroad is of sufficient value for us to risk jeopardizing the reopening of schools in September.
Tomás Ryan is associate professor in the school of biochemistry and immunology at Trinity College Dublin and chair of the European FENS-Kavli Network of Excellence