One metric that the Mexican government has used is suspected deaths. But it's not clear what evidentiary threshold they're insisting upon to declare that a death was probably caused by swine flu. Indeed, the government appears to have shifted on that point, perhaps under pressure from foreign an international health organizations.
On Tuesday, the Mexican government announced that the number of suspected deaths from swine flu was 159, up only slightly from 152 on Monday.
Then on Wednesday, Health Minister Jose Cordova reduced the figure to 84, saying that tests had shown that swine flu wasn't the cause of many of almost half of the 159. Yesterday, according to a transcript provided by a reporter, Cordova went before the cameras again, and stuck with the 84 figure, saying explicitly that the WHO and CDC had been working with Mexico to get those numbers.
But he also announced that the government would no longer provide figures for suspected deaths. Reading between the lines, it looks like, under pressure from outside health organizations, the Mexican government was forced to accept that its "suspected deaths" numbers weren't reliable.
The government has also been giving out the number of deaths that have been scientifically confirmed to have been caused by swine flu. On Wednesday, Cordova had put that number at 8. He updated it yesterday to 12, and this morning, the government raised it to 15, based on lab tests, while saying the virus was "not so aggressive" as initially feared.
This is the number of Mexicans who have been confirmed to have swine flu, including the confirmed deaths. Earlier this week, the government put that number at 49. On Wednesday, the Mexican president, Felipe Calderon, said it had risen to 99. Yesterday, Cordova again raised it to 260, and this morning to 328.
So the "confirmed deaths" and "confirmed cases" numbers seem to be the best thing to focus on. It's looking like many people who are getting the virus are recovering, so the deaths number may be more relevant -- but no one knows whether that trend will continue.