Researchers in the United States simulated a pandemic to determine optimal strategies for distributing vaccines. Their results can help inform public health initiatives and supply chain protocols during flu season.
Every year, influenza causes thousands of deaths in the United States alone. Vaccines can prevent the spread of the flu virus, provided they are efficiently allocated. During pandemics, limited time and strained resources make strategic vaccine allocation critical for reducing death tolls.
During the avian flu pandemic of 2009, vaccines in the United States were distributed by the Centers for Disease Control and Prevention in ratios proportional to each state’s population. However, the distribution within each state to local providers was not well documented, with few states collecting detailed vaccine administration data at provider facilities. With uptake rates varying from place to place, some locations had surplus inventory while others were left wanting for vaccines when the flu season ended.
Due to this disparity, researchers at the Georgia Institute of Technology and North Carolina State University in the United States undertook a study to quantify the importance of geographic vaccine inventory data in improving vaccination campaigns during pandemics. Their work was published in PLoS One.
Using existing demographic and commuting data from 2015 to 2017, the researchers set up two models simulating the spread of influenza through the state of Georgia. The model assumed that uptake rates varied geographically but were constant over time. One model accounted for the government tracking inventory levels geographically and reallocating vaccines accordingly, while the other maintained a strictly population-based approach. In doing so, they hoped to compare the infection rates between population-based vaccine allocation against the population and inventory-based allocation.
The researchers found that population-based allocation reduced the infection rate by 22.4% while population and inventory-based allocation reduced it by 23.4%. In the simulation, population and inventory-based allocation also reduced the amount of leftover inventory from 827,000 to 152,000 and resulted in higher vaccination rates in the population.
The study suggests that tracking inventory levels geographically during a pandemic can maximize the impact of vaccination efforts while reducing supply chain expenses due to wasted inventory.
To determine the feasibility of gathering the data necessary to make these reallocations, the next step would be to assess the cost of implementing electronic inventory tracking systems across an entire state. In conjunction with the results from this study, this kind of future research would provide a more accurate picture of the cost-effectiveness of population and inventory-based vaccine allocation.
Written by Agustin Dominguez Iino, BSc
Reference: Li Z, Swann JL, Keskinocak P. Value of inventory information in allocating a limited supply of influenza vaccine during a pandemic.PLoS One. 2018 Oct 25;13(10):e0206293. doi: 10.1371/journal.pone.0206293. eCollection 2018.