Fever screening was implemented at border crossings after the global outbreak of SARS, which prompted countries to set up border control strategies.2 According to the included studies, fever screening at international airports was generally not effective at detecting H1N1-2009 and other influenza viruses, or dengue fever. One study performed in a controlled setting assessed how well IRT readings correlated with conventional methods and found only moderate correlation. The study concluded that IRT would not be suitable as a routine screening tool due to the high number of false positives. Relatively low sensitivity and positive predictive values were also seen in studies looking at fever as a predictor of influenza or dengue fever. The reason for these results may be due to the delayed appearance of febrile symptoms for these infectious diseases. Infection associated with the influenza virus begins a few hours before the onset of symptoms, and the viremia of dengue begins one day before the onset of febrile symptoms, making it difficult to detect cases via fever screening.8
The Ebola epidemic in West Africa was declared a public health emergency of international concern by the World Health Organization on August 8, 2014.4 The Ebola virus has an average 8 to 10 day incubation period (range 2 to 21 days) during which the traveller would experience no symptoms.4 This would make it difficult to detect travellers who have been recently infected with the virus at border screenings.
Fever screening in the included studies consisted of a combination of health declaration forms, IRT, a conventional temperature measurement and laboratory testing to confirm diagnosis. Despite using all of these methods, results showed that fever screening was not a very effective strategy at detecting infected individuals. A limitation of this review was the lack of studies that assessed how border control strategies would mitigate the risk of disease outbreaks.