This week we learned that Abbott Laboratories received an FDA Emergency Use Authorization for a faster and cheaper Covid-19 test than anything currently on the market. Technically it’s an antigen test, but detecting the nucleocapsid protein of SARS-CoV-2 will detect actively replicating infection because it’s a key part of the virus’ structure.
Fast and cheap testing is one of the ways to bring travel back to normal. It would allow customers to travel with confidence, knowing that those around them are virus-free. And it would allow destinations to open up, knowing that people shedding the virus weren’t entering.
While some destinations today will allow people to enter or skip quarantine with a recent test, receiving a negative result within three days of travel is no guarantee that the person is negative when they travel. That’s why many destinations won’t take a negative result (which can also be faked), or require quarantine and additional testing on top of a negative result.
Rapid tests at the airport could be used to screen passengers and give confidence that trips aren’t spreading the virus, bringing them into a destination. And yet this breakthrough probably isn’t going to help air travel at all any time soon.
Here’s how the test works:
In this case, a nasal swab is taken, and several drops of solvent are used to put that sample onto the beginning of the absorbing strip inside the card. As it soaks up along the length of the strip, the sample will encounter a zone of antibodies that recognize the Np antigen, and these antibodies are also attached to nanoparticles of gold. This gold-antibody-Np complex is carried along in solution further along the strip until it runs into another antibody zone, one that’s immobilized on the solid support and which will bind the gold-antibody-Np complex molecules tightly. That stops them in their tracks and allows the gold nanoparticles to pile up enough to be visible as a pink or purple line. Along the way, the sample has also crossed a zone containing another soluble gold conjugate species as a control, which gets carried along until it runs into another separate zone of immobilized antibodies specific to it. The presence of a pink control line means that the test has been performed correctly; absence of such a control line means that the whole test has been messed up somehow and needs to be run again.
The federal government announced a deal on Thursday to buy 150 million tests – that’s three months’ capacity – for $750 million. Priorities for testing include school re-opening over air travel.
The manufacturer will begin shipping in September and reach 50 million tests a month in October. It’ll be late December before the government’s monopoly on initial supply ends.
As for accuracy of the test:
- 97.1% sensitivity (2.9% false positives)
- 98.5% specificity (1.5% false negatives)
Nearly 3% of tests could yield a false positive, so in an air travel context that could mean perhaps 20,000 people per day denied boarding despite not having the virus even with current low levels of trael. And by the time this is available we could be close to Covid-19 being manageable in the U.S.
There’s a real chance that Covid-19 could become manageable in the U.S. by the end of the first qurter of 2021, and a great chance it’s manageable in the second quarter. In a few months we should have monoclonal antibodies, though in limited supply and at a high cost, but for many people this could be tantamount to a cure – making as much of a difference or more than a vaccine.
And much of the U.S. will have seen enough infection by then that the virus won’t spread as quickly as it did in the Northeast, and then the Sun Belt, before it becomes more manageable via treatments and vaccines even if the first generation of vaccines is hard to distribute (mRNA vaccines requiring extremely cold temperatures to store, vaccines requiring two doses) and having only limited effectiveness. We may still see another wave in rural areas that haven’t yet seen big spikes in the virus before that though.
My hope – and I’m really optimistic – is that bioscience will make this controllable before people can be reinfected in large numbers and with severity. We won’t be through the crisis worldwide in the first half of 2021 though, because it will take time and expense to scale and distribute vaccines and treatments and because poorer countries may have less access despite efforts to the contrary. And that will have a continued effect on air travel.