Apparently, there is some sort of influenza bug in the air and there is an alarming amount of cases out there; enough to - according to the press - warrant the IMSS apparently issuing an 'alert' and proceeding to apply vaccines to people already in the hospital system. There are reports that there are no more vaccines in the Mexico City area.
This information was corroborated the other night by a local doctor I happened to have coffee with who said that here in the Yucatan the IMSS did not want to issue a general alert as this would cause a rush on the available vaccines, which, according to this source, were scarce. There is, he said, indeed a shortage of vaccines in spite of a report in the local press citing the contrary for the state of Yucatan. He suggested that if you can, to get a shot.
Influenza is a health problem that affects everyone, but those most susceptible are the very young and older people.