Nowcasting the 2022 mpox outbreak in England #

Christopher Overton, Sam Abbott, Rachel Christie, Fergus Cumming, Julie Day, Owen Jones, Rob Paton, Charlie Turner, Tom Ward

10:30 Wednesday in 2Q50/51.

Part of the Epidemiology and statistical learning session.

Abstract #

In May 2022, a cluster of mpox cases were detected in the UK that could not be traced to recent travel history from an endemic region. Over the coming months, the outbreak grew, with over 3000 total cases reported in the UK, and similar outbreaks occurring worldwide. Following the COVID-19 pandemic, local health systems were strained, and therefore effective surveillance for mpox was essential for managing public health policy. However, the mpox outbreak in the UK was characterised by substantial delays between symptom onset date (and specimen collection date) and these events being reported. These delays led to substantial backfilling in the epidemic curve, making it challenging to interpret the epidemic trajectory in real-time. Many nowcasting models exist to tackle this challenge in epidemiological data, but these lacked sufficient flexibility. As part of the UKHSA mpox response, a novel nowcasting model using generalised additive models was developed to correct the mpox epidemic curve in England and provide real-time surveillance of the epidemic. This model benefited from close collaboration with individuals involved in collecting and processing the data, enabling temporal changes in the reporting structure to be built directly into the model, which improved the robustness of the nowcasts generated.