Puerto Rico is leading COVID-19 vaccination efforts in the United States, with 89.7% of adults already fully vaccinated (1). However, many other regions are struggling to gain that level of traction, if any. Less than 1% of people in developing countries are fully vaccinated (2). Because Pfizer–BioNTech’s and Moderna’s respective mRNA-based SARS-CoV-2 vaccines still require ultracold temperatures for long-term storage, vaccine distribution in remote locations is arduous without appropriate cold-chain infrastructure. Puerto Rico’s success in vaccinating its population demonstrates how…