An evaluation of the Zambia influenza sentinel surveillance system, 2011–2017

Simusika, Paul; Tempia, Stefano; Chentulo, Edward; Polansky, Lauren; Mazaba, Mazyanga Lucy; Ndumba, Idah; Mbewe, Quinn K.; Monze, Mwaka

We evaluated the performance of the Zambia ISSS over a 7-year period, 3 years from its inception. Overall, based on the evaluated indicators, the system performed satisfactorily with a mean system score of 2.6 (moderate to good performance). The system demonstrated its utility according to its objectives by (i) monitoring the temporal trends of influenza virus circulation; (ii) monitoring the circulating influenza virus types and subtypes annually and enabling the detection of pandemic influenza A(H1N1)pdm09 in 2009 [3] and in subsequent years, (iii) assessing the contribution of seasonal influenza viruses to mild (ILI) and severe (SARI) respiratory illness; (iv) assessing the burden of influenza-associated illness [14] ; and (v) generating isolates to contribute to the annual influenza vaccine formulation. Nonetheless, the ISSS was not able to identify groups at increased risk of influenza-associated severe illness (as the necessary variables were not collected in the CIF), one of the objectives of the surveillance system. Strengths of the system included the quality of data generated, its flexibility to monitor viral pathogens other than influenza viruses [24] , its potential expandability, its stability over the review period, and its relatively low cost. Identified weaknesses were poor geographic representativeness, lack of timeliness in shipping samples from remote sites, and low sustainability in the absence of external funds.