Dutch participatory surveillance framework for evaluating evolutionary changes on SARS-CoV-2 affecting Rapid Diagnostic Test sensitivity in 2022 - 2023.

Abstract

Background Rapid Diagnostic Tests (RDTs) have been pivotal in the diagnostics for SARS-CoV-2 and policies surrounding self-isolation. When self-testing policies are in place a decreased sensitivity of the virus to RDTs can give benefits for viral spread. However, to monitor for reduced sensitivity of RDTs we rely on the collection of SARS-CoV-2 positive samples from RDT negative patients. Infectieradar, a national participatory surveillance that registers influenza-like symptoms is used as a framework to study false-negative RDT results due to emergence of new virus variants. Methods Participants report weekly on RDT use and symptoms linked to Acute Respiratory Illness (ARI). Each week, all RDT positive and a sample of 200 among RDT negative but symptomatic participants were invited to send in nose throat swabs (NTS). SARS-CoV-2 Ct-values are determined using RT-PCR on NTS samples for RDT positive and RDT (false) negative participants and compared. Sequencing is performed on all eligible samples for phylogenetic analysis of the SARS-CoV-2 nucleocapsid protein and the whole genome sequence. NTS samples of participants with discordant RT-PCR and RDT results are also analyzed using RDTs by professionals in the laboratory. Results Between October 2022 and October 2023, our study had 16,893 participants and we collected 1,757 self-test-positive/NTS PCR positive samples and 359 self-test-negative/NTS PCR positive samples (RDT-/PCR+). These participants were asked to take a SARS-CoV-2 RDT upon symptoms. Within SARS-CoV-2 PCR positive participants, we did not find characteristics that differ in SARS-CoV-2 RDT negative versus positive participants. There were no associations with specific changes in the N protein nor did our phylogenetic analysis show clustering of RDT negative samples. Conclusion Evaluating brand-specific RDT performance in Dutch population and false-negative RDT analyses, led to no evidence for SARS-CoV-2 evolution affecting RDT sensitivity. The participatory surveillance program Infectieradar is a powerful tool for our national surveillance on acute respiratory illnesses, as well as for research purposes. Since this framework offered both self-testing and the gold standard of PCR testing results.