Reopening tourism is necessary in order to restore Hawaii’s economy and to allow thousands of willing and able workers to get back to work.

However, a proposal that allows arriving travelers to bypass the 14-day quarantine with a single “pretest” taken before departure is unsafe for Hawaii and unsafe for Hawaii’s tourism workers.

Claims that a negative pretest means that a traveler is not infected with coronavirus are not accurate. For travelers coming from regions with low levels of COVID-19 (such as New Zealand several months ago), a negative pretest may be a reliable indicator that a person is uninfected. However, for travelers from COVID-19 hot spots, the numbers are quite different.

Hot spots can have test positivity rates of 40% or higher; while many studies indicate that the false negative rate for COVID-19 testing (the proportion of people infected with coronavirus that nonetheless receive a negative test result) is in the range of 20-30%.

If Hawaii tourism returned to pre-COVID levels of over 10 million visitors annually, and if a fifth of them came from hot spots with an average test positivity rate of 10%, then we could expect 115-170 infected visitors to arrive each day (3,500-5,000 each month) having passed their pretest, which would allow them to skip quarantine.

In contrast, Hawaii on Monday reported 90 new cases of COVID-19 in the past 24 hours, and the numbers have been holding relatively steady. Relying on a single pretest result could wipe out all the gains we’ve made in fighting the pandemic.

Tourism industry workers exposed to infected tourists could become infected themselves, and bring the disease back to their families and communities, allowing renewed community spread.

A possible solution is to retest travelers on arrival. This could be done at the airport with a rapid test. If negative, the traveler could proceed without quarantine. If positive, a third test could be conducted to make sure it’s not a false positive; if confirmed as a true positive, quarantine would then be necessary.

The cost of testing could be borne by travelers, by the state, or shared between them. In any case, the benefit to Hawaii of eliminating most quarantines would outweigh any costs.

As with any measure short of strictly-enforced quarantine for all arrivals, pretest plus retest on arrival would still leave some risk: Occasionally an infected traveler might receive false negative results on both the pretest and the retest. Still, two tests are better than one, and would strike a more reasonable balance between burden and benefit than relying on a single test.

One test alone leaves Hawaii too exposed to the risk of importing more COVID. To protect Hawaii our plan should be: Pretest, then retest.

Bruce Kessel is an Oahu physician; the views expressed here are his own.