The international trade in human vaccines before COVID-19

The recent COVID-19 pandemic has highlighted the importance of global access to human vaccines. There is, however, no empirical work on either the unequal distribution of international trade or on its determinants. Applying a gravity model to the UN Comtrade database between 2000 and 2019, we explain the patterns of bilateral trade across 116 countries. Using the Poisson Pseudo-Maximum Likelihood methodology, our results show that inequalities in international vaccine trade have steadily increased. In general, supply and demand drivers play a role in explaining the flow of human vaccines. The impact of these drivers varies depending on the income level of the importing country. High-income countries intensify their flows with demand factors such as GDP per capita, or supply factors such as the location of big pharmaceutical companies. Conversely, low-income countries receive more vaccines according to their population. Our results show that a poor country that houses a big pharmaceutical company acts as an exporting platform to developing and poor countries. Middle-income countries present features similar to rich countries both by producing more and also by exporting more. The imbalance endangers the global fight against the current COVID-19 pandemic.