COVID-19: Time to Focus on Public Health Measures at Points of Entry

In this piece, I examine why there was a rather stunning lack of understanding of risks and mitigation efforts in responding to COVID-19 at Points of Entry (POE) and in International Travel. I also point out why, as the global economy readies to resume, intervention at POE is now more urgent than ever.

The COVID-19 outbreak is still evolving and although we do know a number of things with a good degree of certainty — that Social Distancing will ‘flatten the curve’ as shown in the now-viral graphs — there are other things that seem rather unclear. Among the things commentators seem to be unsure about is the value of entry screening measures at Points of Entry and other public health interventions in international travel short of border closures. Why did the United States and most of Europe do nothing to screen travellers travelling through their points of entry at any point in this outbreak while other countries (Singapore, Nigeria, Taiwan, Thailand, South Korea etc.) have aggressively screened passengers on arrival?

I believe two things happened to create this asymmetry in strategy: one is a rather stunning blind spot in thinking about risk and [based on, accompanied by?] an equally stunning lack of understanding of pandemic preparedness and response as it concerns international travel. I also think the capacity for a nationally coordinated response to a pandemic at POE (although critical, is a deceptively simple tool, easy to take for granted), does not exist in any practical sense in the countries that decided not to deploy measures at point of entry.

The Risk Blindspot

The dizzying, breakneck speed with which COVID-19 moved across countries and took hold in them underscored again the importance of international travel. A public health threat, whether accidental or of malicious, or deliberate origin is only a flight or two away from establishing a foothold in the world. If airports, seaports and land borders are the portals through which such a spread happens, then it makes sense that we start our attempts at mitigation or prevention at these places. But airports (as with other POEs) are transit points — the majority of users spend an average of 40 to 60 minutes at airports (significantly less at land borders). The window for detection is slim. A number of attempts have been made to model the chance of detecting an infectious disease at the airport via visual and temperature screening (which is the primary surveillance heuristic deployed at POE). As expected, the chance is low, but not zero. The chance that someone ill with an infectious disease will be detected is often put somewhere between 15% to 25%. In other words, 75% of people with COVID-19 may slip through airports undetected. What these analyses often fail to get is that any non-zero chance that we can detect an imported case of infectious disease is huge — and setting up structures to enable and optimize such detection is priceless in the early stages of a response. This is the risk blindspot many decision-makers have. As Nicholas Taleb often says, a lack of evidence that something works is not the same as evidence that it doesn’t. As it happens, we actually have some evidence it works. A number of countries (Nigeria, Thailand, Singapore, Rwanda etc.) have all detected cases of COVID-19 at POE. How much headstart did this detection give them, how much exposure did they manage to avoid? We will never know. This is how to think about risk, especially risks that are of an existential order, like a pandemic — we need to assume that the single case we may detect in 10 years of entry screening was heading to a football stadium, a rave, a megachurch service or otherwise presents a super-spreading potential. Will we miss a lot more people who will come in asymptomatic? Yes. But to abandon the non-zero chance of POE detection is to be irresponsible and reflects a lack of understanding of how to engage with risks.

Again, the point of POE detection and response is mitigation and providing the National Health Surveillance System a heads start, not ‘stopping the outbreak or disease’. Putting in place entry screening measures is a very low cost, highly optimizable strategy with the potential to massively affect the outcomes of a national response to an outbreak. Even if the only value to entry screening is somehow lengthening the containment phase, delaying the outbreak (no nation implementing entry screening hopes to stop outbreaks happening via entry screening), this is still extremely valuable. Articles like this, in Sciencemag (and elsewhere), that are scornful of the screening process and cite asymptomatic travellers slipping through the airports as evidence that the process doesn’t work are dangerous and shows an ignorance of how global/public health works. The value of entry screening goes beyond the ability to detect ill passengers in order to ‘stop an outbreak’ (now, pay attention, because this is the main gist), it is an opportunity to get ahead in the contact tracing game if one of the travellers who ‘slipped through’ turns up ill, it is an opportunity to conduct one-on-one risk communication to oblivious travellers who may have been exposed, it is an opportunity to prime persons of interest for self-reporting in-country, it is also a trust-building device between public health authorities and the public — a dynamic that is currently at its most fragile globally, and when askew, is the fuel for worsening an outbreak. The intention is never to stop the outbreak at POE, the intent is to mitigate the amount of amplification international travel gives to the outbreak. But, in fact, and as I will show shortly, it is possible to stop new outbreaks (or new flares, as it were) of COVID-19 via measures at POE and in international travel using the same set of strategies that have worked for mitigating the international spread of infectious diseases like Yellow Fever.

The necessity of National Coordination at Point of Entry

the second reason I believe most countries failed to implement any kind of entry screening is that, although it seems like a very simple thing to do, they simply lack the immediate affordance to execute such strategies. During an emergency, putting together a plan that stations a number of health workers at airports to get people to fill forms and monitor body temperature may seem like a rather straightforward thing. But points of entry, especially airports and seaports, are notoriously complex places, and international travel is a highly ‘over-optimized’ industry that is fragile to even the slightest disruptions. Regulators, businesses and Security agencies are always working tight-ropes to optimize ‘facilitation’. Introducing public health measures without a pre-existing coordinating mechanism is doomed to produce chaos as witnessed recently at US airports immediately after the US ban on travel from Europe. This is why airports and seaports should have Public Health Emergency Contingency Plans and why countries should have one that integrated all POE-specific plans and provides and national coordination platform. They may be called ‘contingency plans’, but set up properly, these plans are effective coordination mechanisms rather than a list of to-dos during an emergency. They establish a mechanism for collaboration that makes moving very quickly in the early stages of an outbreak painless. This was a key recommendation of the International Health Regulations (2005) and of the Joint External Evaluation tool, the comprehensive WHO global health security monitoring and evaluation framework. A revised version of this tool has dispensed with the requirement to have a National Public Health Emergency Contingency Plan for Point of Entry. I think it was a mistake. I had the opportunity to lead Nigeria through the process of developing a National Public Health Emergency Contingency Plan for Point of Entry. Nigeria recently operationalized and constituted a national POE committee for Public Health Emergencies, ahead of schedule. It is early days for this plan and its committee, however, one clear lesson from this process is that a coordinating mechanism that exists outside the forcing device of a Public Health Emergency is critical and may help prevent the necessity for more extreme measures like border closures and travel restrictions. Linking security and law enforcement, businesses and other transport and point of entry agencies to public health effectively is a vital part of the mitigating the impact of a pandemic.

Urgent point of Entry priorities

So what should be done on a global level to focus on or prioritize interventions in POE and International Travel. A couple of things;

• A renewed focus on individual airport and seaport contingency plans for public health emergencies as a mechanism for effective coordination. How this is operationalized for preparedness is essential to how stakeholders will respond in the event of an emergency. A national coordination mechanism in the form of a TWG or response committee is essential. It is important to anchor this in the preparedness or contingency plan that integrates all other existing Emergency Response or Contingency plans — those developed by private entities (Airlines, Terminal Operators, etc.) and those set up by regulators councils and associations (like aviation regulators, maritime organizations etc.).
• New measures beyond passenger screening need to be contemplated for responding to COVID-19 at POE in the coming months. These measures will include vaccination and providing proof of vaccination before travel (when a vaccine becomes available), using rapid test kits to test departing/arriving travellers from countries with sustained community transmission, etc. This will enable international travel restriction to be eased without significantly raising risks to other countries.

In the coming weeks, a lot of the discussion is going to dwell on how to ease the global economy back on track without significant risk of new flares. The key to doing this is to get public health interventions in international travel right.