COVID-19 vaccinations in Bhutan – Mix-and-Match to Boosters: An experience

Abstract

Bhutan – a landlocked least developed country in the Himalayas – vaccinated 94% of its adults with the first dose of COVID-19 vaccine in March-April 2021, 90.2% with second dose in July 2021, and 89.1% with booster (third) dose by March 2022.The country used COVISHIELD (Oxford-Astrazeneca) vaccine for the first dose but decided to pursue a heterologous prime-boost strategy (“mix-and-match”) for the second dose using Moderna’s mRNA vaccine for adults.Bhutan rapidly rolled out Pfizer and Moderna vaccines for 12 to 17-year-olds through a school-based vaccination strategy followed by booster doses: 78.6% of adolescents aged 12–17 years were vaccinated with the first dose by August 2021, 92.8% with second dose by November 2021, and 79.7% with booster (third) dose by March 2022. More than 97% of children aged 5 to 11 years have received Pfizer’s Comirnaty vaccine for their first dose.Bhutan is steadily vaccinating its population and might soon become one of the few least developed countries to achieve herd immunity-level vaccination coverage with more than 80% of its population fully vaccinated.