RESUMO
BackgroundCOVID-19 positivity rates reported to the public may provide a distorted view of community trends because they tend to be inflated by high-risk groups, such as symptomatic patients and individuals with known exposures to COVID-19. This positive bias within high-risk groups has also varied over time, depending on testing capability and indications for being tested. In contrast, throughout the pandemic, routine COVID-19 screening tests for elective procedures and operations unrelated to COVID-19 risk have been administered by medical facilities to reduce transmission to medical staffing and other patients. We propose the use of these pre-procedural COVID-19 patient datasets to reduce biases in community trends and better understand local prevalence. MethodsUsing patient data from the Maui Medical Group clinic, we analyzed 12,640 COVID-19 test results from May 1, 2020 to March 16, 2021, divided into two time periods corresponding with Mauis outbreak. ResultsMean positivity rates were 0.1% for the pre-procedural group, 3.9% for the symptomatic group, 4.2% for the exposed group, and 2.0% for the total study population. Post-outbreak, the mean positivity rate of the pre-procedural group was significantly lower than the aggregate group (all other clinic groups combined). The positivity rates of both pre-procedural and aggregate groups increased over the study period, although the pre-procedural group showed a smaller rise in rate. ConclusionsPre-procedural groups may produce different trends compared to high-risk groups and are sufficiently robust to detect small changes in positivity rates. Considered in conjunction with high-risk groups, pre-procedural marker groups used to monitor understudied, low-risk subsets of a community may improve our understanding of community COVID-19 prevalence and trends.
RESUMO
BackgroundPre-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. MethodsWe 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. ResultsAmong 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. ConclusionsThis 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 Maui District Health Offices projected ability to accommodate 10 infected visitors daily in 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.
