If Conejo Valley Unified School District faced the same predicament again, it probably wouldn't have closed Newbury Park High School—even for one day—because of swine flu.

Hindsight is always 20-20, though, and the district reacted responsibly under the circumstances that existed on Monday. When somebody came down with swine flu at NPHS, the district had to respond cautiously.

There was no other choice.

People must err on the side of carefulness if there's even the possibility that lives are in the balance.

There wasn't enough information to react differently because nobody was 100 percent positive that the new flu is relatively weak, at least the type that found its way to America.

It doesn't seem as lethal as the swine flu in Mexico. The virus may be losing its toxicity. Americans might have greater resistance. Our healthcare is superior, and we probably eat a more nutritious diet that includes vitamins and antioxidants. These, too, might be factors.

We can thank our lucky stars that swine flu isn't the second coming of the black plague, at least this time around. There also seems to be evidence that the swine flu virus isn't as virulent as other more common strains of influenza that spread worldwide every year during the cold and flu season.

The problem is that viruses mutate.

Even now, swine flu might evolve into a stronger and more lethal virus.

Nobody wants to close any school unnecessarily. It causes all sorts of problems and is particularly stressful for working parents. But knowing what the district knew and when it knew it, there was no choice.

If children had died because the school remained open, who would have accepted responsibility for that?

NPHS had to be closed at least temporarily. Now that classes have reopened, it will quickly become a faded memory.