Assessing the utility of the COVID-19 epidemic Situations of Concern classification system in guiding operational responses to the pandemic in the WHO African region: retrospective analysis

Abstract

During a public health emergency, early implementation of response activities is crucial for saving lives and protecting livelihoods. The COVID-19 pandemic, declared by the World Health Organization (WHO) on March 11, 2020, posed a global public health crisis that required timely decision-making despite limited data and capacity. In this context, WHO's Regional Office for Africa (AFRO) developed the Situations of Concern (SOC) classification system to assess and monitor epidemiological risk across its 47 Member States. We conducted a retrospective analysis to evaluate the performance and operational utility of the SOC system. Using weekly country-level COVID-19 surveillance data, we found that the system demonstrated strong alignment with epidemic wave patterns, with a sensitivity of 83% and specificity of 88%. SOC classifications supported timely operational decision-making in over 70% of documented support instances. Effective management of limited resources through SOC assessments also helped ensure fair distribution of support across communities. Our findings suggest that adaptable classification systems like SOC can provide effective decision-support under conditions of limited data availability, improving outbreak preparedness and response in resource-constrained settings.

Keywords: COVID-19; SAR-CoV-2; Situation of Concern; WHO African region; epidemic.

Figure 1

COVID-19 epidemic Situation of Concern (SOC) alert classifications as they relate to observed case incidence (here, shown for daily timesteps).

Figure 2

Temporal trends in number of SOC epidemic concern classifications (Alert or Resurgence classification) and epidemic waves over time stratified by time period during the COVID-19 pandemic.

Figure 3

Weekly SOC classification of Member States from epidemiological week 23-2021 to week 11-2023. The red vertical line signifies when SOC criteria were revised to adapt to the shift in epidemiological characteristics provoked by emergence of the Omicron variant. The following colors signify the SOC classification in place for each week: Green = no or low concern, Yellow = Very High Incidence, Orange = Alert (rising or reduced concern, prior to revised SOC criteria; rising concern following revised SOC criteria), Red = Resurgence, and Blue = Alert (Reduced Concern), White = No classification.

Figure 4

Lead (negative) and lag (positive) times (in weeks) for issuance of SOC Alert and Resurgence classifications compared to epidemic events (start or peak of national COVID-19 epidemic waves).

Figure 5

Time-stratified operational utility of the SOC epidemic concern classifications.