Better late than never, but San Francisco International Airport (SFO) has become the first U.S. airport to introduce rapid COVID-19 testing. Screening is currently only for airport and airline employees, but it is one step closer to a testing regime that could re-open skies.
Rapid COVID-19 Testing At SFO
Per Chris McGinnis, the testing site is located in the international terminal (G gates) in a ground floor courtyard. The site had a soft opening last month for select airline employees, but is now open to all airport workers and airline employees. Technicians use a toaster-sized Abbott Labs device to analyze samples. Results are available in 13 minutes or less.
While we’e seen elaborate testing sites pop up all over the world, they have been few and far between in the USA. Delta Air Lines offers rapid testing in a few of its crew lounges, but we have not seen any major airport offer such rapid testing to passengers.
Authorities are split on such tests. Trade groups like the Airlines Council International (ACI) and the International Air Transport Association (IATA) believe such tests can quickly replace mandatory quarantines.
ACI World Director General Luis Felipe de Oliveira said:
“Unnecessary quarantine measures are particularly harmful to passenger confidence as international air travelers have no assurance that, if they make flight arrangements, they will be able to return to their place of departure to continue their daily lives. The imposition of such restrictions fails to take into account other options such as testing.”
But a UN International Civil Aviation Organization (ICAO) task force cautions:
“Rapid tests cannot be a precondition for travel due to their unreliability or impracticability. It should be noted that the rapid testing of all passengers prior to departure would not be operationally viable unless more real-time, rapid and reliable testing becomes available.”
But that’s exactly why SFO’s new rapid testing site is great news. Indeed, tests that take a day or more to return are practically worthless. But imagine rapid PCR tests that passengers could take before stepping onto an international flight. This could re-open borders on a far shorter time horizon than waiting for a vaccination.
CONCLUSION
I understand that these sorts of rapid tests have a fail rate of around 20%. But if passengers take a rapid test prior to departure and again upon arrival, it should minimize a great deal of that uncertainty. The world is ready to travel again. Rapid testing presents the most viable way to safely travel again. Thus, I’m excited about the progress SFO is making and hope that such testing will soon expand to passengers and be available across the United States.
image: SFO
The World is ready for travel without this ridiculous cavalcade of testing – it exists ONLY to give people some sense of safety. The virus is going to be everywhere, its just a matter of time.
A 20% failure rate doesn’t seem great to me, but I’m hoping someone with a statistics or probability background can elaborate on the practical implications of that number.
Are we correct to assume that 80% of the time the test is correct, whether positive or negative? Or is it only 80% correct in not producing a false negative? Or does that even matter if we take the conservative approach and simply ignore false positives, treating anyone testing positive as truly positive.
How does the accuracy of the test impact the probability of a false positive or a false negative? Are those probabilities high enough that we can make reasonable policy decisions on allowing people to fly or not?
Assuming a hypothetical infection rate of 10% among any sample group of people, I feel like I can “screen” everyone with a test that only claims people aren’t infected, and still be correct 90% of the time.
As it was explained to me by someone far smarter than I am, the issue with “rapid” tests is false negatives when a patient is either early in the stages of infection, or is entirely asymptomatic. A 20% failure rate there is obviously more problematic than if the issue were false positives. As you note, you can treat a false positive as the real deal until further testing rules out an infection, and deny boarding. But a false negative would allow the passenger to continue on their journey (assuming they are asymptomatic).
False negatives and false positives are based on concepts called “negative predictive value” and “positive predictive value” and vary greatly based on how much covid is floating around.
If only 1 in a million people have Covid, it’s much more likely to get a false positive. If one in 20 have it, it’s much more likely to get a false negative. Look it up. The calculations are less statistics and more basic math. You can do it in minutes on your own.
20% failure rate on measuring something with a probability of <1 % is the definition of useless.
I’ll wait for the experts to weigh in concerning their accuracy. But if these tests provide people with a crutch like the worthless TSA does, then I’m all for them…
I don’t think we should encourage SARS-CoV-2 testing to become a “regular” part of travel, because once these things are implemented, they are very hard to remove. Imagine the expense a family would incur as a result of testing requirements. Do we want travel to once again become only something that rich people can afford? I’m planning to travel to the EU soon and looking forward to enter via a country *without* a testing requirement, because I don’t think it makes sense to get a test, given I could then be infected two seconds later on the train into town.
@James
For some reason, I don’t see this being as difficult to remove as other measures we’ve put in place to combat “terrorism.” Especially without robust contact tracing, there’s no single smoking gun that’ll pin blame on a security apparatus for failing to catch someone flying with SARS-CoV-2.
I imagine much of the political pressure for removing shoes at security has to do with the fact that if just one person sneaks explosives in the hollow of a shoe through security and detonates it on a plane, we’d all immediately know who to scapegoat. The consequences of “screwing up” are just too visible. It’s like a 911 operator choosing to ignore what’s almost certainly a prank call rather than sending a squad car out to investigate. You can’t just stop checking everyone’s shoes.
Meanwhile, two years from now, if this initiative is phased out and a cluster of a few dozen unrelated people come down with COVID two 5-14 days after a flight. Who’s going to know? I think this one can actually be phased out without much public outcry.
Meanwhile, I don’t think any of us want to make testing a regular part of travel or make travel “less egalitarian,” as Gary Leff would put it. However, if the only remaining alternatives are between “no travel whatsoever” and just “getting over the risk,” I think rapid testing is better than both.