Delays in travel restrictions have contributed to the current COVID-19 outbreak

Effective, strong and early action is critical at this time to prevent a large scale COVID-19 outbreak in Sri Lanka. Despite WHO advice to the contrary, travel restrictions have an important role to play, and are the most effective tool we have since we can still hope to prevent and contain a local epidemic. Unfortunately, despite taking early action to restrict and screen arrivals from China, Korea and Iran, the government delayed too long to impose further restrictions given what the data were saying. This and gaps in implementation have contributed to the sudden increase in cases starting on 10th March.

I don’t think that anybody in Sri Lanka disagrees with the policy of imposing quarantine restrictions from February on arrivals from Hubei province in China, the rest of the Chinese mainland, Korea and Iran, and then the travel ban on Korea, Italy and Iran from last week. But if we support such a policy, the delays in imposing restrictions on all travelers from Europe, other Middle Eastern countries, USA and Australia were completely illogical.

A benchmark for identifying high risk countries
The risk to Sri Lanka of traveler from a particular country depends on the level of local transmission in that country in the past two weeks, since the average person develops symptoms within ten days of infection with by the corona virus. One easy measure of that using publicly available data is the number of newly reported cases per million population in the previous ten days. I’m going to call this the attack rate. The likelihood that an individual visitor to Sri Lanka is infected by corona virus will be related to this attack rate. But I should add that if the epidemic is spreading in that country, this number will actually understate the infection risk since the attack rate will be climbing, and visa versa.

The attack rate in the Chinese mainland excluding Hubei province peaked at 5.4 cases per million on 8 February 2020. After that point it began to fall. Given that nobody disputes the desirability of travel restrictions on Chinese visitors, this attack rate of 5.4 is a useful benchmark for when we should be concerned about infection risk in other countries. I should share that the attack rate in Hubei peaked at 640 cases per million a week later on 14 February, but we can safely ignore Hubei, since nobody has been able to leave that province since early February.

The number of high risk countries has surged since late February
The ten day attack rate passed 5.4 cases/million in Korea on 22/02, in Bahrain on 25/02, Italy and Kuwait on 26/02, Iran on 29/02, countries in the Schengen area other than Italy on 06/03, Israel on 08/03, UK on 11/03, and Australia and USA on 13/03. With the exception of Korea, infection rates continue to climb rapidly in all these countries, so attack rates are now even higher. In case you are wondering, the attack rate in Hubei dropped below 5.4 on 16 March.

Trend in COVID-19 attack rates, 15 February–16 March 2020 (New cases per million population in past 10 days)

Just to be clear, during the past four weeks the infection risk from travelers from Europe, North America, Australia and a whole range of other countries surpassed the highest level ever reached in mainland China. And also to be clear, the data on this have been freely available to everyone in the world and our government.

Comparison of COVID-19 attack rates in China and selected countries (16 March)

If you think the restrictions on visitors from China were warranted, there is no rational basis to think that similar or more draconian restrictions on these other countries have not been needed for weeks. In the case of Europe, because there are normally no border controls between countries in the Schengen area, it makes no sense to differentiate between such countries. We should have imposed restrictions on all 26 countries in the Schengen area ten days ago. It is not at all surprising and was entirely predictable that the recent surge in cases has been driven by visitors from Europe and the Middle East.

I normally avoid making public endorsements, but in this case the evidence clearly supports the call by the GMOA to impose blanket travel restrictions on all countries until we have a more systematic arrangement in place to handle visitors.

What should we do?
Sri Lankans have a right to enter the country, so we cannot prevent them from returning. Economic and social life still has to continue, and we are going to face this challenge for several more months. So complete bans on planes and ships arriving in Sri Lanka is not going to work. We have to balance the risks and manage and not prevent arrivals. Complete travel bans will only make sense as a temporary measure until we get more realistic arrangements in place.

I strongly recommend that we adopt a policy similar to that of Australia and New Zealand. We should require visitors from all countries, regardless of whether they are Sri Lankan or foreign nationals, to either self-quarantine or go to a quarantine centre for 14 days. Who should be mandatorily quarantined should be based on the infection risk in the countries they have been in recently, but I would be inclined to include in this list Italy, Korea, Iran, Qatar, Bahrain, Israel and Kuwait.

If we want travel to continue – and we do need it to continue, we need to switch to a much more effective self-quarantine regime, since the government cannot easily quarantine tens of thousands of people. This will need significantly more resources to ensure effective enforcement of the regulations including routine monitoring of those in self-quarantlne, and possibly emergency legislation to expedite rapid punishment of those who fail to comply. Such public punishment will be needed as in Singapore to make an example, as sadly many anti-social individuals will not comply. I would also suggest that we look at what China and India have done, which is to provide hotels as quarantine options for those who are able to pay the cost themselves.

1 thought on “Delays in travel restrictions have contributed to the current COVID-19 outbreak

Leave a Reply