A study suggests that as many as one-third of Mexicans may have been exposed to the coronavirus by the end of last year.
Coronavirus antibodies were found in 33.5% of samples from blood banks and medical laboratory tests in Mexico unrelated to COVID-19. The random samples were taken between February and December 2020.
The levels varied according to regions. The highest exposure rate was found in the northwest, from Baja California to Chihuahua, at 40.7%. The lowest came in western states, at 26.6%.
In general, areas along the U.S. border had higher rates.
Victor Borja of the Mexican Social Security Institute says the nationwide average may have risen as much as 10 percentage points following a steep rise in cases in January.
But even if the exposure rate is currently as much as 43.5%, Borja stresses that the country is still far from herd immunity.