Methodology

Infectious disease resurgence post pandemic map

Airfinity has collaborated with Bloomberg News to map the post-pandemic resurgence of 13 select epidemic-prone infectious diseases. The spike size is determined by the change in reported cases from a post-pandemic year (2022-onwards), as of 1st June 2024, with highest reported incidence against a single pre-pandemic ‘baseline’ year within the 2017-2019 period, preceding the COVID-19 pandemic. The ‘baseline’ year for pertussis may be set to an earlier date, contingent on the timing of the most recent epidemic in the specific country pre-pandemic.

The diseases included in this analysis are chickenpox, cholera, dengue, measles, Mycoplasma pneumoniae, parvovirus B19, invasive Group A Streptococcus, pertussis, influenza, respiratory syncytial virus (RSV), wild poliovirus type 1 (WPV1), vaccine-derived poliovirus and tuberculosis.

The analysis relies heavily on data reported by all countries globally, which in turn depends on the robustness of their infectious disease surveillance and reporting systems. Consequently, the data by no means represents the true burden of these diseases within populations, as many cases might go undetected due to asymptomatic presentations and mild clinical symptoms, leading to undiagnosed cases, as well as limited resources for testing. Furthermore, the disease data presented here is not exhaustive, with large gaps for both notifiable and non-notifiable diseases. Some countries/regions might be overrepresented than others due to their superior surveillance and reporting systems. In addition, changes in testing levels post-pandemic likely affect recent disease incidence, resulting in large post-pandemic spikes that might incorrectly imply significantly higher disease incidence or change disease epidemiology.

Although still incomplete, 2024 data is included in the analysis. This inclusion is based on the observation that certain diseases have exhibited an already higher number of cases in the first months of 2024 than in any other year since the pandemic subsided, sometimes exceeding pre-pandemic levels. In such instances, the fold change is calculated based on year-to-date cases for 2024, with the expectation that these figures will rise as more months’ data becomes available. For visualisation purposes, wild poliovirus type 1 and vaccine-derived poliovirus subtypes have been combined into a single disease named polio.