  The COVID-19 pandemic has caused a dramatic surge in demand for personal
protective equipment (PPE) worldwide. Many countries have imposed export
restrictions on PPE to ensure the sufficient domestic supply. The surging
demand and export restrictions cause shortage contagions on the global PPE
trade network. Here, we develop an integrated network model, which integrates a
metapopulation model and a threshold model, to investigate the shortage
contagion patterns. The metapopulation model captures disease contagion across
countries. The threshold model captures the shortage contagion on the global
PPE trade network. Results show that, the shortage contagion patterns are
mainly decided by top exporters. Export restrictions exacerbate the shortages
of PPE and cause the shortage contagion to transmit even faster than the
disease contagion. Besides, export restrictions lead to ineffective and
inefficient allocation of PPE around the world, which has no benefits for the
world to fight against the pandemic.
