Emergence of COVID-19 variant XFG not linked to higher rates of sore throat or altered severity: Evidence from participatory surveillance in the Netherlands.

OBJECTIVES: Here, we investigate symptoms linked to the new SARS-CoV-2 variant XFG using an evidence-based method to determine possible elevated levels of sore throat and severity as suggested by on-line news reports and social media. STUDY DESIGN: Participants (n = 39,937) in the participatory surveillance program, Infectieradar, weekly report respiratory symptoms and severity of disease. In addition, SARS-CoV-2 self-test results are reported and a representative subsample of all participants with symptoms sent a nose-throat swab for molecular diagnostic testing and sequencing. METHODS: We compared symptom prevalence, symptom burden and severity of disease in week 28 to week 40 in 2025, when SARS-CoV-2 strain XFG was dominant, with the same period in 2024, in which the KP.3 variant was most abundant. We compared these two periods through adjusted odds ratios and estimated marginal means to provide evidence for possibly altered symptomatology or disease severity. RESULTS: Sore throat was not significantly higher during the COVID-19 wave in 2025, compared to 2024, nor were any other symptoms. Additionally, the number of symptoms and severity of disease in the two periods is comparable. CONCLUSIONS: We conclude that sore throat is not indicative for the emerging XFG variant, nor that worse severity of disease is experienced during current COVID-19 cases in the general population.