After nearly 2 years of calling for rapid tests, the U.S. is finally catching up to the rest of the world with these crucial public health tools. There is no time better than now, as the Omicron quickly spreads in the U.S., and is more infectious and better able to break through the immune protection we’ve built up through vaccines and previous waves of the virus.
Almost as soon as Omicron was announced, some countries started to enact travel bans to stop the spread, but it was too late. The new variant had already started to appear around the world. But, finally, we’re slowly learning. Instead of closing U.S. borders as happened in the past, President Joe Biden announced new rules for international travel.
I commend the administration for enacting more effective public health measures that limit people from getting on a flight with an active infection. All inbound international travelers to the U.S., regardless of vaccination status and nationality, need to take a COVID-19 test that shows negative test results within one day of their flight. This is a vital change from the earlier requirements that a test needed to be taken within 72 hours of departure. That timeframe never worked because a test taken too many days before a flight can be negative at the time of collection, but that same person can be positive for COVID-19 by the time the flight takes off, with their outdated negative lab report in hand.
We need to adjust our thinking about the approach to testing to ensure we’re using more effective tools.
First, travelers to the U.S. should rely on rapid antigen tests because the test results are almost immediate, versus the 1-3 days that laboratory PCR tests take to get results.
Second, people shouldn’t just use any self-test at home or in their hotel by themselves. Instead, there will be a requirement for test authentication to verify the test-taker’s identity and test results. This test authentication can be accomplished in a couple of different ways. It could be an in-person point-of-care test in the country of origin at a clinic or pharmacy, as long as it comes with a verified laboratory report that authenticates both the user identity and the negative result. Alternatively, travel back to the U.S. can use a telehealth proctored test with a test kit the traveler picks up before leaving the US, and can use from anywhere in the world. Companies like eMed (where I am the new Chief Science Officer) and Azova are two digital health platforms where a certified proctor verifies who is taking the test and validates the test results over a web connected device then sends the certified digital results directly to the individual and, when needed, the airline.
In the U.S., these companies allow rapid home-tests to become crucial tools in this pandemic because the test results can be reliably reported to the relevant public health departments and enable downstream options including sequencing of variants and, importantly, can enable fast initiation anti-viral treatment (test-to-treat) without entering a hospital or laboratory. That is especially important as we now have two effective anti-COVID-19 pills that need to be taken with a few days of the onset of symptoms.
The Type of Test Matters
In the U.S., people have relied on PCR testing for most of this pandemic, but for limiting transmission in daily life and for travel, a point of care rapid test is almost always the better tool for a few reasons. A PCR test can take 1-3 days to get results, which allows transmission to occur while waiting for results and, for travel, misses the time frame window. A PCR test is so sensitive that it can show positive test results for weeks or months after someone is no longer infectious, which have caused unnecessary isolations and quarantines (when people test positive after they are no longer infectious) and can unnecessarily impact travel plans for long periods of time. The faster results from a rapid antigen test also allow people to take action to isolate immediately and, most importantly, specifically when they are still infectious.
Testing after entry is also important
Another important question to ask is “what if you’re negative when you get on the flight, but you become positive days after you land?” While some countries like China have a required substantial quarantine periods for travelers arriving from international destinations, that is not feasible in the U.S. Along with pre-flight testing the Biden Administration should consider recommending further testing in the week after arrival. Each traveler could take the test along with a telehealth proctor daily for 5 days, with reported results. To make this feasible, individuals could be provided with five rapid tests at the airport upon arrival into the U.S. Individuals could be registered as they pass through passport control. If an individual turns up positive on the rapid test, they would be asked to isolate, and if the test is not used, an automatically generated message would be sent reminding them to test that day, or quarantine. While the exact program would need to be refined, including any efforts to ensure compliance, the technologies exist to reduce the risk of new variants passing into the U.S. without the need for onerous quarantines or other economically damaging programs.
What About the Fully Vaccinated?
There’s a lot of discussion about whether those who are fully vaccinated should have to take a test before travel. There’s a good reason everyone needs to test regardless of their vaccination status. This goes to the point that vaccines are highly effective at limiting disease and death, but they are not as effective as we originally hoped at limiting the spread of the virus. Unfortunately, a few months post vaccination, the vaccine’s ability to stop the transmission of the virus is significantly reduced. Because of that reason, those who are vaccinated need to participate in other crucial strategies to limit spread.
This is almost certainly even more true for Omicron which seems to be spreading more efficiently than other variants among vaccinated individuals both because it is likely intrinsically more infectious, and its unique constellations of mutations make it more likely to break through previously acquired immunity.
Testing is how we see, track and diagnose this virus. It is among the most crucial and fundamental pandemic response tools for both public health and medicine. To be most effective, testing has to be accessible, fast, cost effective, and must work to identify those at risk of spreading the virus to others. Combining with telehealth can allow at-home rapid tests to be useful for public health reporting, test sequencing, and for fast diagnoses and initiation of antiviral medications in a time frame that works. We can travel safely and keep our borders open if we follow a robust testing program. Omicron is quickly becoming a formidable threat in our war with this virus and not the last variant to spread, but rapid testing can help us limit its spread and prepare for the next wave.