International travel could safely reopen through the widespread adoption of high-quality rapid antigen testing shows new research. The study carried out by Oxera and Edge Health shows that antigen testing can be highly effective in detecting COVID-19 infections.
The new modelling also shows that the current ten-day quarantine period required of passengers arriving in the UK isn’t necessary for passengers arriving from the majority of countries if widespread testing is adopted.
Michele Granatstein, Partner at Oxera and Head of its Aviation practice, said:
‘When international travel reopens testing is likely to remain part of the strategy for controlling COVID. The type of testing regime chosen will make the difference in how quickly the travel industry recovers.
The choice of a rapid test would be a real boost to the global travel and international business community, and our research shows it can be as effective as other testing regimes and as effective as a ten-day quarantine.’
The efficacy of testing schemes will be a key factor as governments around the world consider how to safely restart international travel. However, there are a number of other factors that need to be considered, including capacity, feasibility, and the costs of implementing different testing schemes. Antigen tests are cost-effective, require little specialist equipment, and can deliver results quickly.
Reducing, or even eliminating, the mandatory quarantine period for travel from the majority of low- or medium-risk countries would go a long way towards helping the airline and travel industries recover from the pandemic.
Previous research has shown that quarantine requirements have been a deterrent to prospective travellers. Since 15 February, passengers from ‘red list’ countries—those deemed as being high-risk for COVID-19—have had to pay £1,750 each to quarantine at a hotel.
Evidence from global testing regimes has indicated that the risk of air passengers travelling with COVID-19 is no more than 1%. As vaccination programmes are accelerated and the number of cases fall within the community, the prevalence of COVID-19 in air passengers will be reduced even further.
To date, 31 million adults in the UK have received their first vaccine dose. However, as other countries lag behind, the requirement for testing of passengers will be a mainstay for the foreseeable future.
Effectiveness of antigen tests compared to PCR
Antigen tests are slightly less sensitive than the more commonly used PCR tests when screening international passengers on arrival: PCR testing detects 72% of infectious days, compared to 65% for a LAMP test and 63% for an antigen test. However, the difference in performance narrows considerably in tests administered three days after arrival, with PCR testing detecting 79% of infectious days, compared to 75% for antigen testing.
As PCR is proven to be the most accurate test for detecting COVID-19 infection, it has been adopted more widely than other forms of testing. However, use of antigen testing is becoming more widespread across many jurisdictions, both for air travel and other activities, such as workplace testing.
Modelling by Oxera and Edge Health also revealed that antigen testing is as effective as a ten-day quarantine period, when compliance with quarantine is taken into consideration. New data suggests that compliance is now higher than previous studies suggested, with 71% following quarantine guidelines until day eight.
Antigen testing on departure also screens more infectious days than a 72-hour pre-departure test. However, carrying out tests on arrival or on departure would be likely to create logistical challenges when passenger numbers begin to pick up. Antigen tests carried out the day before travel would be expected to be as effective in screening infections.
Modelling by Oxera and Edge Health shows that in a sample of 1,000 air passengers with an infection prevalence rate of 1%, the best-performing antigen test would detect all but one cases of infection.
Benefits of antigen testing compared to PCR
So far, PCR swab tests have been the dominant form of testing for COVID-19; however, antigen tests have numerous advantages over these. PCR tests are considerably more expensive than antigen tests and results need to be processed in a laboratory. As such, PCR testing is unsuitable for airport testing, with a median time of 28 hours to receive results. Antigen tests are cheaper, can deliver results within 20 minutes, are easy to administer and do not require laboratory equipment.
George Batchelor, Cofounder and Director of Edge Health, said:
‘Our studies show that antigen testing can be comparable to PCR in overall effectiveness, with any disparity in sensitivity largely ironed out three days after arrival. When taking into consideration compliance with quarantine, antigen tests administered on departure can be effective at screening for COVID-19 infections.’
‘Tests will reduce the risk of air passengers spreading COVID-19, particularly those from countries where prevalence rates are low. If governments accept antigen testing in the coming months, combined with the rollout of vaccination programmes, it will enable the airline industry to get back on its feet safely.’