Even ‘cruises to nowhere’ can’t escape the coronavirus

The passenger who tested positive had tested negative prior to boarding, said Annie Chang, director for cruise at the Singapore Tourism Board.

Though Covid-19 tests are increasingly being relied on to revive the embattled travel industry, testing isn’t failproof. Covid-19 infections are not easily detected during early stages of the disease, and tests can fail to detect active cases too.

Rapid PCR tests, which are both accurate and fast, exist but production is outmatched by demand, said Dr. Shira Doron, infectious disease physician and hospital epidemiologist at Tufts Medical Center.

And even when tests work, passengers may slip through the cracks. Last week, a couple traveled to Hawaii after they both tested positive as part of United Airline’s preflight testing program. The pair has since been charged with reckless endangerment and banned from flying with United.