# A dynamic ensemble model for short-term forecasting in pandemic situations

## TL;DR

This paper introduces a dynamic ensemble model to improve short-term forecasts during pandemics by adapting to changing conditions and using additional data sources like Google searches.

## Contribution

The novelty lies in using a dynamic ensemble model that adapts over time and incorporates secondary metadata for pandemic forecasting.

## Key findings

- Dynamic ensembles outperformed individual models in robustness during pandemic forecasting.
- Incorporating Google search data improved the model's adaptability to changing pandemic conditions.
- The approach was tested on multiple diseases including COVID-19 and Influenza.

## Abstract

During the COVID-19 pandemic, many hospitals reached their capacity limits and could no longer guarantee treatment of all patients. At the same time, governments endeavored to take sensible measures to stop the spread of the virus while at the same time trying to keep the economy afloat. Many models extrapolating confirmed cases and hospitalization rate over short periods of time have been proposed, including several ones coming from the field of machine learning. However, the highly dynamic nature of the pandemic with rapidly introduced interventions and new circulating variants imposed non-trivial challenges for the generalizability of such models. In the context of this paper, we propose the use of ensemble models, which are allowed to change in their composition or weighting of base models over time and could thus better adapt to highly dynamic pandemic or epidemic situations. In that regard, we also explored the use of secondary metadata—Google searches—to inform the ensemble model. We tested our approach using surveillance data from COVID-19, Influenza, and hospital syndromic surveillance of severe acute respiratory infections (SARI). In general, we found ensembles to be more robust than the individual models. Altogether we see our work as a contribution to enhance the preparedness for future pandemic situations.