López Obrador's administration has long resisted adopting measures like mandatory face masks, mass testing and travel restrictions that have been used in many other countries.
Assistant Health Secretary Hugo López-Gatell had said as recently as August that there was no scientific evidence to justify giving booster shots, and suggested they were part of a campaign by vaccine manufacturers to increase sales.
“This proposal is being strongly pushed by the pharmaceutical companies, but it has been rejected by international organizations ... because there is no scientific evidence indicating the need for booster shots," López-Gatell said at the time.
The government also long resisted vaccinating minors, but recently relented and began administering shots to youths between 15 and 17 years of age.
Of special concern are the nation's teachers, almost all of whom got the CanSino Chinese vaccine in the spring. There have been suggestions that single-dose vaccine's protection begins to wane.
Mexico's test-confirmed coronavirus death toll stood at 293,950 on Tuesday, but because the country does so little testing, many people have died without tests. The government's own analysis of death certificates indicates the real toll is about 448,658.
Officials have been downplaying the threat posed by the Omicron variant first identified in South Africa, saying the new strain illustrates the need to get more vaccines to poorer countries.
“It's not that the new variant is terrible,” López Obrador “It's that the poor countries of the world have been abandoned."
True to form, López Obrador said there would be dance music at a massive gathering he is planning in Mexico City's vast main plaza Wednesday to celebrate his first three years in office. The president, as usual, said face masks would be optional.
“Those who want to wear face masks can do so,” López Obrador said. “We are against authoritarianism.”