"Starting next Monday, January 10, we are going to start a new mass vaccination process with a fourth dose or a second booster dose," said Pinera in a press conference.
Chile has one of the world's highest vaccination rates and has been hailed as a model for its response to the pandemic, having administered two doses to over 85% of the population. About 57% have received a third booster shot, according to Our World in Data.
Chile's announcement comes as the highly contagious Omicron variant is spreading worldwide, with several countries reporting all-time high COVID-19 case loads even among vaccinated populations. Cases in Mexico have more than doubled in the past week, while Peru imposed new restrictions this week.
"The success that Chile has had in the vaccination process (...) puts us among the best countries in the world in the way we have managed to combat this pandemic," Pinera added. "And with this fourth dose we seek to maintain this leadership position and protect the health and lives of our compatriots." The vaccines for the fourth dose will be a combination of the same shots that have been used so far in Chile, including Pfizer-BioNTech, Sinovac and AstraZeneca, said Health Minister Enrique Paris.
This combination of different vaccines between the first and fourth doses should allow "an improvement in the immune response," Paris explained.
Chile reported its first case of the Omicron variant at the beginning of December and has confirmed 698 cases of this variant have been reported, the vast majority corresponding to people who traveled outside the country.