A Rapid Method to Evaluate Pre-Travel Testing Programs for COVID-19: A Study in Hawaii

Hou, A. T.; Pang, G. C.; Mills, K. M.; Bayudan, K. L.; Moore, D. M.; Medina, L. P.; Pang, L. W.

Background Pre-travel testing programs are being implemented around the world to curb COVID-19 and its variants from incoming travelers. A common approach is a single pre-travel test, 72 hours before departure, such as in Hawaii; however this raises concerns for those who are incubating or those infected after pre-travel testing or during transit. We need a rapid method to assess the effectiveness of pre-travel testing programs, and we use Hawaii as our case study. Methods We invited travelers departing from Kahului main airport at the end of their visit to Maui (major tourist destination among the Hawaiian islands) and performed COVID-19 PCR testing. Eligible participants needed a negative pre-travel test and a Hawaiian stay [≤] 14 days. We designed for anonymous testing at the end of travel so that travel plans would be unaffected, and we aimed for [≥] 70% study participation. Results Among consecutive eligible travelers, 282 consented and 111 declined to participate, leading to a 72% (67-76%, 95% confidence interval) participation rate. Among 281 tested participants, two were positive with COVID-19, with an estimated positivity rate of 7 cases per 1,000 travelers. The top states of residence are California (58%) and Washington (21%). The mean length of stay was 7.7 {+/-} 0.2 days. Regarding pre-travel testing, 87% had non-nasopharyngeal tests and 66% had self-administered tests. Conclusions This positivity rate leads to an estimated 17-30 infected travelers arriving daily to Maui in November-December 2020, and an estimated 52-70 infected travelers arriving daily to Hawaii during the same period. These counts surpass the the Maui District Health Office's projected ability to care for 10 infected visitors daily on Maui; therefore, an additional mitigation layer for travelers is recommended. This rapid field study can be replicated widely in airports to assess effectiveness of pre-travel programs and can be expanded to evaluate COVID-19 importation and its variants.