Impact of prophylactic vaccination strategies on Ebola virus transmission: A modeling analysis

Abstract

Ebola epidemics constitute serious public health emergencies. Multiple vaccines are under development to prevent these epidemics and avoid the associated morbidity and mortality. Assessing the potential impact of these vaccines on morbidity and mortality of Ebola is essential for devising prevention strategies. A mean-field compartmental stochastic model was developed for this purpose and validated by simulating the 2014 Sierra Leone epidemic. We assessed the impacts of prophylactic vaccination of healthcare workers (HCW) both alone and in combination with the vaccination of the general population (entire susceptible population other than HCW). The model simulated 8,706 (95% confidence intervals [CI]: 478-21,942) cases and 3,575 (95%CI: 179-9,031) deaths in Sierra Leone, in line with WHO-reported statistics for the 2014 epidemic (8,704 cases and 3,587 deaths). Relative to this base case, the model then estimated that prophylactic vaccination of only 10% of HCW will avert 12% (95% CI: 6%-14%) of overall cases and deaths, while vaccination of 30% of HCW will avert 34% of overall cases (95% CI: 30%-64%) and deaths (95% CI: 30%-65%). Prophylactic vaccination of 1% and 5% of the general population in addition to vaccinating 30% of HCW was estimated to result in reduction in cases by 44% (95% CI: 39%-61%) and 72% (95% CI: 68%-84%) respectively, and deaths by 45% (95% CI: 40%-61%) and 74% (95% CI: 70%-85%) respectively. Prophylactic vaccination of even small proportions of HCW is estimated to significantly reduce incidence of Ebola and associated mortality. The effect is greatly enhanced by the additional vaccination even of small percentages of the general population. These findings could be used to inform the planning of prevention strategies.

A model and predictions for COVID-19 considering population behavior and vaccination

“…Bubar et al 21 accounted for the possibility of ruling out individuals with antibodies from receiving the vaccine using a serological test, and added an age-dependent effectiveness of the vaccine. Effects of vaccination have been examined in past outbreaks such as the 2009 H1N1 Swine Flu outbreak and the 2014-2016 Ebola epidemic [22][23][24][25][26][27] . These studies have introduced population compartments that separate the population by their location and give insights into what locations should receive vaccines first 28 .…”

A model and predictions for COVID-19 considering population behavior and vaccination

“…Bubar et al 21 accounted for the possibility of ruling out individuals with antibodies from receiving the vaccine using a serological test, and added an age-dependent effectiveness of the vaccine. Effects of vaccination have been examined in past outbreaks such as the 2009 H1N1 Swine Flu outbreak and the 2014-2016 Ebola epidemic [22][23][24][25][26][27] . These studies have introduced population compartments that separate the population by their location and give insights into what locations should receive vaccines first 28 .A critical aspect of COVID-19 vaccination that remains unexplored is a population's behavioral changes during the prolonged period of vaccination.…”

A hybrid simulation model to study the impact of combined interventions on Ebola epidemic

“…Vaccination is known as one of the most effective interventions for reducing the morbidity and mortality during the epidemic outbreak. Multiple mathematical modeling analyses aimed to evaluate the impact of vaccination during the outbreak of Ebola epidemics have been undertaken [25][26][27][28][29]. Based on their study [24], Merler S. et al [29] further developed a spatially explicit microsimulation model in order to study the effectiveness of ring vaccination strategies.…”