They considered one side of the coin, but not the other side. That is, Americans get immunized more, but they also get flu outbreaks more.
Flu is transmitted by coughing and sneezing ideally at 40F and low humidity. The higher the temperature and humidity, the more dependent flu is on being transmitted by surface contamination.
For this reason, flu outbreaks are not common in Mexico. This implies *not* that Americans have better immunity, but that Mexicans have less immunity to flu.
This is ironic, because Mexico has some truly savage bacteria, made more so by the ability of Mexicans to buy antibiotics over the counter. But this doesn’t affect viruses like the flu.
Very interesting ‘yefragetuwrabrumuy’, I think there is a lot of common sense in your comments
You know, you made thing about something. We were in Florida about a month ago when that really freakish cold snap hit, it got cold even in way south florida, wonder if Mexico got really cold and the flu (being as the conditions were right) spread like crazy to a populace unaccustomed to it?