Chile on Wednesday began administering booster shots to people already vaccinated with Sinovac’s COVID-19 vaccine, as reported by the National Post.

Chile’s immunization campaign has seen upwards of 67% of its population fully vaccinated, predominantly with Sinovac’s CoronaVac. However, authorities last week said studies had shown a booster was necessary to shore up immunity.

"Studies have shown that precisely at approximately 6 months there is a decrease (of antibodies) and that is why we have decided …to give this booster dose," remarked health minister Enrique Paris.

The country began offering a dose of the Oxford-AstraZeneca vaccine to citizens aged 86 and older who received their initial shots before March 31.

Fernando Leanes, a World Health Organization representative in Chile, said that there was not yet sufficient data to support the use of booster shots.

"With limited supply, you have to consider the global perspective," Leanes said. "There are countries that have not been able to complete the vaccination of their health workers and that is a danger for all countries."