THE TOKENISM behind President Gloria Macapagal-Arroyo?s two-day self-imposed quarantine shows us what happens when government policy follows short-term political objectives. At best, it accomplishes nothing. At worst, it sends the wrong signals, about the wrong priorities.

By and large, the Department of Health has responded to the A(H1N1) pandemic well. We must note, however, the curious timing of its new guidelines for handling swine flu cases; by some coincidence, the President is the first beneficiary. There is no need, the DoH announced, for Ms Arroyo to place herself under self-quarantine. All the same, Malacañang said, with political ?pogi ? points obviously in mind, the President would remove herself from circulation for the grand total of one day. What the medical significance of a 48-hour timetable was, the Palace did not elaborate.

We do not dispute the DoH?s downgrading of the A(H1N1) threat. As Education Secretary Jesli Lapus pointed out last week, we cannot suspend classes every time a swine flu case is confirmed. And given the medical community?s current best estimate that the virus is a low-level risk, and considering the continuing rise in the number of confirmed cases, we think the DoH did right in shifting the priority from prevention to mitigation.

And yet we cannot abandon contact-tracing altogether. As we learn from a new study, the results of which were published (as a letter to the editor) in the prestigious New England Journal of Medicine, the A(H1N1) virus was spread largely through the international air transportation system.

The study, conducted by scientists and scholars from Canadian hospitals and universities, compared Mexico air travel statistics from March to April 2008 with the geographical distribution of swine flu cases around the world. It found a significant correlation: ?Of the 20 countries worldwide with the highest volumes of international passengers arriving from Mexico, 16 had confirmed importations [of the new virus] associated with travel to Mexico as of May 25, 2009.?

A thumping confirmation of conventional wisdom?the notion that air transportation networks were largely responsible for the dissemination of the new virus?the study suggests that the health department?s decision to forgo the contact-tracing that it conducted so effectively in the first weeks of the health scare looks decidedly short-term in outlook.

Consider what the study found: ?Although the correlation between the international movements of travelers and H1N1 is generally intuitive, our findings suggest that quantitative analysis of worldwide air-traffic patterns can help cities and countries around the world better anticipate their risks of importing global infectious diseases.?

The results even suggest a certain air-traffic threshold: ?countries receiving more than 1,400 passengers from Mexico were at a significantly elevated risk for importation.?

What this means first of all is that national health authorities must continue to work with airport managers to enforce a system for filtering airline passengers. After all, a virus can attach itself to any passenger, even side-tripping presidents (or visiting defense secretaries from lone superpowers).

What this means secondly is that national health authorities must continue to trace the lineage, as it were, of every confirmed swine flu case, not only because the information will help the mitigation effort, but also because it can help draw a dynamic picture of the country?s vulnerabilities, and thus of possible pathways for the next new virus.