What effect might border screening have on preventing importation of COVID-19 compared with other infections? A modelling study

Abstract

The effectiveness of screening travellers for signs of infection during times of international disease outbreak is contentious, especially as the reduction of the risk of disease importation can be very small. Border screening typically consists of arriving individuals being thermally scanned for signs of fever and/or completing a survey to declare any possible symptoms, and while more thorough testing typically exists, these would generally prove more disruptive to deploy. In this paper, we utilise epidemiological data and Monte Carlo simulation to calculate the potential success rate of deploying border screening for a range of diseases (including the current COVID-19 pandemic) in varying outbreak scenarios. We negate the issue of testing precision by assuming a perfect test is used; our outputs then represent the best-case scenario. We then use these outputs to briefly explore the types of scenarios where the implementation of border screening could prove most effective. Our models only considers screening implemented at airports, due to air travel being the predominant method of international travel. Primary results showed that in the best-case scenario, screening has the potential to detect 46.4%, 12.9% and 4.0% of travellers infected with influenza, SARS and ebola respectively, while screening for COVID-19 could potentially detect 12.0% of infected travellers. We compare our results to those already in the published literature.

Investigating the potential benefit that requiring travellers to self-isolate on arrival may have upon the reducing of case importations during international outbreaks of influenza, SARS, Ebola virus disease and COVID-19

“…From what has been shown above, when compared to the results described in our previous work [1], it is clear that the addition of any of the considered self-isolation periods dramatically increases the rates of detection of infected travellers after arrival. This is likely because requiring travellers to selfisolate for some extended period allows them considerably more time to incubate than afforded by the flight alone, and thus makes them much more likely to become detectable by testing.…”

“…In this paper we have described a minor adjustment to the Monte Carlo based model we described in previous work [1], in order to study the effect that requiring travellers to self-isolate may have on disease detection rates. While other authors have evaluated the possible impacts that screening travellers solely upon arrival may have on reducing the risk of importing various diseases [7]- [9], less research has been conducted into the effects of enforcing a period of self-isolation.…”

“…We then explain how we have expanded the model to incorporate the additional self-isolation period under study. For a complete breakdown of the original model, we redirect the reader to the supplementary material included with the original work [1].…”

“…In a previous paper [1], we described an adaptable model which could be used to assess the effectiveness of implementing a strict screening policy at airports during international disease outbreaks. We subsequently used this model to evaluate the probability that screening would be able to detect infected travellers on arrival across a range of scenarios, given that they were well enough to fly (i.e.…”

“…In this paper, we investigate whether the addition of requiring arriving travellers to undergo such a self-isolation period to the border screening process might improve detection rates enough to present an attractive alternative during such outbreaks. We achieve this by way of modifying the model presented in the original paper [1] to allow for this additional period of isolation. As such, this paper should be seen as an addendum to the previous work.…”