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

BackgroundRapid 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. MethodsParticipants 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. ResultsBetween 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. ConclusionEvaluating 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.