A version of this opinion piece was first published by the South China Morning Post on 14 October 2021.
Singapore’s vaccination rate is one of the highest in the world, above 80 per cent. Encouraged by this, the city-state has tried to reopen and renormalize. However, the recent COVID-19 surge has grown faster than expected, hospitals are feeling the impact, restrictions were reintroduced, and mobility remains well below pre-pandemic levels.
Here and abroad, there is a vigorous debate between two groups on how to ‘exit’ from the pandemic.
On one side are the ‘eliminationists’. They point to China which advocates that the safest way to defend against COVID-19 is to eliminate it. Lockdowns and quarantines, they argue, are a price worth paying to keep everyone safe. They highlight that eliminationist economies have overall grown faster than mitigation economies. Eliminationists note the potential threat of novel variants and that long COVID is incompletely understood.
On the other side are those advocating to re-open society. They argue that, since vaccines protect the vast majority from severe disease, allowing Delta to spread is acceptable and even desirable for post-infection immunity. The re-openers point to well-vaccinated countries in Europe that lifted regulations without major spikes in deaths. Re-openers say that ongoing travel and social restrictions will do needless damage to society, mental health, and the economy.
Both camps make strong cases. But what if we could do both? What if we could strongly suppress COVID-19 while also re-normalising society? Some believe this can be done with at-home testing.
In the pandemic’s first days, the WHO urged the world to “test, test, test”. By identifying and isolating cases, they said, the chains of transmission could be broken. Polymerase chain reaction (PCR) testing—a powerful way to detect viral genes (RNA)—was widely implemented.
Later, another kind of test became available: the antigen rapid test (ART). ART kits are like a pregnancy test for COVID: they require no special electronics or skills, and can be used by anyone. For the past year, Dr Michael Mina, an assistant professor of epidemiology at the Harvard T.H. Chan School of Public Health in the US, has been advocating that the widespread use of ARTs could force COVID-19 transmission into collapse. He bases this on ART’s three critical advantages.
First, ARTs can reliably detect if someone is in the roughly weeklong infectious phase, when they secrete millions of viruses. This high-virus phase corresponds to the interval when ARTs are highly sensitive, making them an almost ideal tool for someone to know when they are contagious. Critics of ARTs say that PCR is much more sensitive, but this can actually be a liability when it detects a residual amount of RNA during a waning, non-infectious case. Data from a study by the UK Covid-19 Lateral Flow Oversight Team indicates that ART sensitivity for contagious cases, even when asymptomatic, is typically around 97 per cent. This means that, with rapid testing, positive individuals can reliably know which few days they need to stay home, while everyone else testing negative can confidently get on with their lives.
Second, ARTs are very fast. The Delta variant becomes infectious 1–2 days earlier than last year’s strains, effectively outrunning PCR tests, which can take days to give a result. An ART can let someone know if they are contagious in just 20 minutes, beating Delta’s pace.
Third, ART technology lends itself to mass production at low cost (although in many places this has not yet been fully realized). ARTs will be most effective when testing is affordable for everyone. Transmission will be more effectively slowed as ARTs are used more widely. Therefore, better control will be achieved when ARTs are low cost or, ideally, free.
Indeed, some European nations have made low-cost ARTs integral to their re-opening strategy. In Germany, the federal regulator has authorized dozens of different ART brands, driving prices under €2.00. In the UK, households can order a free pack of seven tests every day, or collect free test packs from local collection points.
However, places like the United States and Singapore have been slower to increase ART availability. The US has stringently regulated ARTs as medical devices, resulting in only a handful of approved home-test vendors, high prices, and shortages. President Biden is moving to fix this, invoking the US Defense Production Act to help increase production and directly buying millions of tests.
In Singapore, one especially clever application is using ARTs in coordination with automated contact tracing: close contacts are given free kits and expected to test daily for a week in case they become positive. However, approvals of home-use ARTs have been relatively slow—just a few brands approved at the time of this writing. Prices at the major retailers remain high, around S$10 per test. In Germany, an ART costs roughly the same as a ride on Singapore’s Mass Rapid Transit (MRT). Broadening vendor approvals should lower prices, so that everyone can afford to test regularly. A survey in the US showed that, if available for U$1.00 (S$1.35), as many as 79% would use ARTs regularly. Low cost would also make it easier for governments and employers to distribute kits freely to citizens and staff.
Whatever we do now is preparation for the next variant wave or future pandemics. Self-testing is already as easy as other hygiene routines like tooth-brushing. We know it can be made as cheap as a daily commute. When that happens, we will find out whether we can crush the pandemic with a new kind of ‘MRT’: mass rapid testing.