Testing strategies for SARS-CoV-2

The implementation of objective-driven and sustainable testing strategies for COVID-19 has supported the overall public health response to the pandemic and helped mitigating its impact on vulnerable populations and healthcare systems, while ensuring that societies and economies continued to function.

Achieving the testing and notification of all people with COVID-19 symptoms in terms of a universal testing strategy is a resource-intensive endeavour. Most European Union/European Economic Area (EU/EEA) countries are transitioning or planning to transition to more sustainable, objective-driven surveillance systems that facilitate the gathering of representative and reliable surveillance data. A recent guidance by ECDC, ‘Operational considerations for respiratory virus surveillance in Europe’, provides Member States with updated surveillance objectives and options to effectively implement this transition.

Well-designed, representative, sentinel surveillance systems in primary and secondary care should remain the main surveillance method for acute respiratory infections. Sentinel systems provide robust epidemiological data that are routinely collected using common syndromic case definitions with reliable denominators, and integral microbiological testing that can be extended to multiple viruses. This makes them ideal as the basis of integrated impact assessment of influenza, COVID-19, and potentially other respiratory virus infections.

It is essential to continue reporting epidemiological information for patients with respiratory symptoms testing positive for influenza viruses, SARS-CoV-2 and other relevant respiratory viruses in non-sentinel primary or secondary care laboratories and registry-based systems, including information on where the specimens were obtained. These data will be used to complement data from sentinel systems, particularly while sustainable sentinel systems are being expanded.

Diagnostic testing should ideally be performed by using multiplex PCR assays to simultaneously detect influenza viruses, SARS-CoV-2 and other relevant respiratory viruses where possible.

Genomic surveillance of SARS-CoV-2 is essential to detect, monitor and assess virus variants that can result in increased transmissibility, disease severity, or have other adverse effects on public health and social control measures. Obtaining timely and accurate information on the emergence and circulation of variants of concern (VOCs) and variants of interest (VOIs) requires robust surveillance systems and a well-defined specimen selection and sequencing strategy which is consistent with the overall respiratory virus monitoring strategies to ensure reliability and interpretability of findings.

ECDC has published guidance for EU/EEA Member States, including sample size considerations and sourcing of specimens to implement genomic SARS-CoV-2 surveillance:

Page last updated 15 Dec 2022