If we have vaccines, why do we still need testing?

Before vaccines became the core tool to fight Covid-19, it was testing. Now, with inoculations on the rise, demand for testing is declining, a development that led diagnostic giant Abbott Laboratories to slash its 2021 profit guidance. The pandemic is far from over, though, and testing will continue to be essential in the struggle to control outbreaks, identify emerging variants and allow for safe reopenings.

The arsenal of tests is evolving. Here are a few of the trends and technologies to watch:

A minute or less

One of the buzziest recent entrants is a Covid test from startup Breathonix that was provisionally approved in Singapore in May. It promises results within a minute of breathing down a tube. Most associate such technology with policing drunken drivers, but there's a lot to like about its use for Covid screening. On top of being pleasantly noninvasive, it doesn't require specialized workers or an offsite lab. Admittedly, the breath analysis isn't as accurate as the "gold standard" PCR test. Still, it's good enough for Singapore's intended use — quick screening of travelers alongside a second rapid test — and likely would work well elsewhere, too.

Excessive focus on accuracy has been problematic at times. PCR tests, for example, can show a positive reading long after someone is infectious. Add in long waits for results, and you end up with information that isn't always useful. The antidote is fast, accessible screening through on-site analysis or self-administered tests that are highly effective at catching people when they're most likely to infect others. In the face of significant gaps in vaccine coverage within and between countries and the looming possibility a seasonal resurgence, screening still has a role to play. 

Tracking a changing virus

With the rise of dangerous variants, it's not enough to test for infection — identifying the strains that are circulating has to be a global priority. Yet few countries are checking enough samples, and efforts have been focused on wealthier nations rather than the under-vaccinated, low-income countries most at risk for severe variant-driven outbreaks.

Genetic sequencing is standard for variant identification, but it's a time-consuming and somewhat expensive process, and many nations lack significant capacity. Luckily, companies including Seegene Inc. and Bio-Rad Laboratories Inc. have developed quicker tests that identify variants. Applied DNA Inc. plans to seek US emergency approval for a testing panel that can screen for seven known strains. Wide use could inform public health leaders; detailed sequencing can be reserved for when it's needed.

A new use for a maligned test

Antibody tests, which measure immune responses to Covid infection, fell out of favor last year after lax regulatory standards allowed inaccurate tests to enter the market. Regulators eventually cracked down, but antibody tests still never drove reopening as some hoped because of uncertainty about what the tests really mean about how safe previously infected people were from Covid. With vaccines promising proven on-demand protection, you might even expect demand to vanish entirely.

However, antibody tests may find a new role driving a faster vaccine rollout. In a recent letter in the medical journal The Lancet, public health and immunology experts suggested that countries skip second shots for Covid survivors, pointing to growing evidence that one is all they need. The move would free up doses for more vulnerable people, with less risk of bad outcomes than a policy of delaying second shots across the board to prioritize first doses. Comprehensive antibody testing would be a prerequisite to enacting such a strategy, and rapid testing would be ideal. NowDiagnostics Inc. received US authorization in May for a self-contained finger stick test that delivers results in 15 minutes, and startup Weavr Health is awaiting authorization for a 10 minute at-home option. Until such tests are widely available, large diagnostic companies such as Abbott, Roche Holding AG, and Siemens AG have all developed multiple antibody assays and are likely hungry for new business.

Lasting immunity

The next big testing goal is measuring how well vaccines are working and how long protection lasts. The US Food and Drug Administration has authorized a growing number of "semi-quantitative" tests that offer an estimate of protective antibody levels rather than just a yes-or-no answer that could serve in that role. The missing piece is an understanding of exactly what those numbers mean over time. 

US regulators currently advise against assessing immunity with antibody tests for that reason. That shouldn't be a lasting interdiction but a call to do the research required to get reliable answers. It may be a matter of standardization and reading existing tests the right way. It's also possible that we'll need more precise techniques or tests that look at other types of immunity, such as assays developed by Adaptive Biotechnologies Corp. and Oxford Immunotec Global PLC that look at potentially important T-cells. Figuring out measures of immunity would allow faster vaccine trials that can measure effectiveness with a blood test and ensure that booster shots only go to those who genuinely need them. And it could give those with weaker immune systems peace of mind that they are or remain protected.

Everyone is looking forward to a time when Covid testing is no longer necessary. Using tests smartly and well can get us to that point faster. 

* Max Nisen is a Bloomberg Opinion columnist covering biotech, pharma and health care