Being 3rd in North America has always been Mexico's place. Right behind the USA and Canada. No surprise there.
There was not an ample supply of vacs available for purchase in the beginning. Uncle Sam, thru Operation Warp Speed, financed research and pre-purchased millions of doses of all kinds of potential covid vacs. That is why all the so called "free" jabs in the USA available to everyone from everywhere.
Not all of that investment produced a viable vaccine. The USA owns millions of doses of Asta Zenica, a vaccine NOT approved by the FDA as safe and not used in the States. We give it away to other countries.
I wonder the real cost of these free vaccines.
I believe Mexico can't purchase vaccines that aren't available to them. Other countries are in front of Mexico in the shopping line. They did procure Cansino, Sputnik and others. In fact there are 7 different vaccines approved for covid in Mexico, 4 more than the USA allows. And they still can't get enough (like most of the 3rd world)
It took Canada a long time to ramp up. Canada needs vaccines for only 40 million people that are completely under their government public health care system. Since they didn't invest and prepay for vaccines, they had to wait their turn too.
Considering all these different vaccines approved around the world didn't exist 18 months ago, I am surprised that over a BILLION people have gotten some kind of jab.