Asymptomatic testing of Covid backed by new research studies

News Desk: Research published today demonstrates how effective widespread testing has been against emerging variants of concern.

Findings from three studies on the real-world use of rapid tests, known as lateral flow devices (LFDs), have confirmed their effectiveness under a variety of conditions, demonstrating the reliability and adaptability of these tests.

The three research papers, two of which have been published by the government today (Wednesday 7 July) and one by Liverpool University yesterday, analysed the use of LFDs in a variety of scenarios: against variants of concern; on patients with high or low viral loads; as part of mass testing campaigns; in the hands of inexperienced users and; with different types of swabs.

Alongside the phenomenal scale and breadth of the rollout of the vaccination programme, and the ‘Hands, Face, Space’ guidance, regular testing is a vital tool in stopping transmission as the country follows the roadmap and starts to reopen.

With around one in three people infected with COVID-19 never developing symptoms, asymptomatic testing allows us to swiftly spot those cases most likely to be infectious. Knowing our rapid tests are effective in identifying the Delta variant means everyone who is currently engaged in regular twice-weekly testing can be confident the test will detect what is now the most common strain in circulation.

UKHSA Chief Executive Dr Jenny Harries:

The UK has now established itself as a powerful testing armoury. Millions of people have been taking lateral flow devices used every week to help us carefully reopen society.

These rapid tests continue to play an integral role in helping us stay on top of this virus by quickly identifying positive cases that may have otherwise gone unnoticed. This enables us to take swift action, preventing asymptomatic cases from becoming outbreaks.

In vitro and clinical post-market surveillance of Biotime SARS-CoV-2 Lateral Flow Antigen Device in detecting the SARS-CoV-2 Delta variant (B.1.617.2)

Analysis of the Innova LFDs and their ability to detect the Delta (B.1.617.2) and Alpha (B.1.1.7) variants of concern found there was no significant change in the sensitivity of the tests when identifying either variant. The government-commissioned research involved academics and scientists from Queen Mary, University of London, Public Health England and the Nuffield Department of Medicine, at the University of Oxford. It drew upon real-world performance data from between 1 April and 2 June 2021 for the most commonly used brand of LFD in the UK. Real-world testing data from over 2,000 cases of the Delta variant was used to investigate whether LFD tested positivity rates are significantly lower than PCR positivity rates in locations where prevalence of the Delta variant is high.

As new variants surface, standard laboratory-based surveillance and clinical surveillance in real world settings, covered by research like this, will be crucial to ensuring these rapid tests remain a useful tool in tracking COVID-19.