In fact, because borders must remain mostly closed, the economic imperative has required so much domestic easing that health risks have risen sharply, as evidenced by soaring infection rates.
If this lopsided approach was suboptimal before, it is getting unsustainable with the Delta outbreak.
VALUE OF BORDER RESTRICTIONS RELATIVE TO DOMESTIC MEASURES
Border measures carry a premium only while they keep the Delta or other variants out. In Singapore for instance, the number of imported cases was a multiple of those spreading in the community before Delta; now they are just a small fraction, because of Delta.
Since it is difficult to determine from the genetic sequencing alone if new variants are more transmissible, the alarm is raised only when they appear in large case numbers at origin, by which time it is too late for border measures to stop them spreading.
When the number of imported cases constitute a small fraction of community ones, the value of border restrictions relative to domestic measures in limiting the spread of a highly transmissible variant starts to fall sharply.
This would suggest that shifting the focus from border to domestic restrictions, for any given health-economy trade-off, would be beneficial. Such a shift would better address economic considerations while providing the best opportunity to contain community spread.
The countries in Europe and North America have recognised this and have moved to progressively open their borders while retaining some domestic protocols and social distancing measures in place to protect the community.
It is time that Southeast Asian countries start planning to move in the same direction even as they ramp up vaccination efforts.