Assessing the impact of the Lebanese National Polio Immunization Campaign using a population-based computational model

Abstract

BackgroundAfter the re-introduction of poliovirus to Syria in 2013, Lebanon was considered at high transmission risk due to its proximity to Syria and the high number of Syrian refugees. However, after a large-scale national immunization initiative, Lebanon was able to prevent a potential outbreak of polio among nationals and refugees. In this work, we used a computational individual-simulation model to assess the risk of poliovirus threat to Lebanon prior and after the immunization campaign and to quantitatively assess the healthcare impact of the campaign and the required standards that need to be maintained nationally to prevent a future outbreak.MethodsAcute poliomyelitis surveillance in Lebanon was along with the design and coverage rate of the recent national polio immunization campaign were reviewed from the records of the Lebanese Ministry of Public Health. Lebanese population demographics including Syrian and Palestinian refugees were reviewed to design individual-based models that predicts the consequences of polio spread to Lebanon and evaluate the outcome of immunization campaigns. The model takes into account geographic, demographic and health-related features.ResultsOur simulations confirmed the high risk of polio outbreaks in Lebanon within 10 days of case introduction prior to the immunization campaign, and showed that the current immunization campaign significantly reduced the speed of the infection in the event poliomyelitis cases enter the country. A minimum of 90% national immunization coverage was found to be required to prevent exponential propagation of potential transmission.ConclusionsBoth surveillance and immunization efforts should be maintained at high standards in Lebanon and other countries in the area to detect and limit any potential outbreak. The use of computational population simulation models can provide a quantitative approach to assess the impact of immunization campaigns and the burden of infectious diseases even in the context of population migration.

Review of poliovirus modeling performed from 2000 to 2019 to support global polio eradication

“…to polio-endemic areas) for US military personnel and nondeployed US military populations [ 163 ]. Focusing on the dynamics of a hypothetical importation of WPV1 from Syria into Lebanon in 2013 to explore the potential benefits of an OPV SIA conducted in Lebanon in November 2013, a 2017 study developed an IB model that demonstrated the importance of the preventive SIA with respect to preventing a potentially large and explosive outbreak [ 159 ].…”

“…Notably, although the populations modeled by the groups differed, the primary conclusions of the application of transmission models to the question of expanding the target age ranges for OPV SIAs emphasized the importance of reaching susceptible children (typically the younger ones and those in undervaccinated subpopulations) as quickly as possible. Some of the modeling groups also highlighted the substantially lower cases (and costs) associated with performing pSIAs to prevent the need for oSIAs [ 34 , 35 , 159 ].…”

Socio-political and organizational influences on national infectious disease surveillance for refugees: A qualitative case study in Lebanon

“…For example, the ESU Acute Flaccid Paralysis (AFP) surveillance team adapted activities to find Syrian refugees after the 2013 polio outbreak in Syria, considering any Syrian AFP case as highly suspected for polio (i.e. a "hot case") and taking additional measures including intensified hospital visits, specimen collection from family members, and vaccination in case residence area [ 34 , 35 ] (Official Letter on hospital active surveillance for AFP, 2014; ESU-01). Similarly, increased Viral Hepatitis A ( VHA ) cases among refugees in 2013 [ 33 , 36 ](ESU-02) led to the creation of a specific VHA reporting form that included refugee status (i.e.…”