Based on the chart review conducted in this study, imported cases of COVID-19 from international travel were not a significant component of the epidemic in Iowa. Only 2 of the 412 patients seen at the travel clinic from October 2019 to its closing in March 2020 tested positive for the disease, and neither of these cases were related to travel. Although the index cases in Iowa were returning travelers, widespread community disease became the predominant means of spread following this initial introduction. There is evidence that workers at meatpacking plants were a major amplifier of the epidemic in Iowa, and the two patients testing positive in this chart review had both been exposed through their work in food plants. To date, a scientific study of the outbreaks in Iowa’s meat packing faculities has not been published. The Centers for Disease Control conducted an epidemioligical review of COVID-19 disease in meatpacking plants, but the Iowa Department of Public Health declined to participate, so Iowa was not included in the study.
This study also examined patients’ planned travel preferences over time and provides a unique glimpse into the evolving anxiety and limitations on travel as the pandemic developed. Intended travel to the Western Pacific region (i.e. China, Japan, Korea, etc.) dropped precipitously throughout the study period. This change in planned travel preferences is likely attributable to the news of the emerging COVID-19 epidemic and the imposition of a level 4 travel warning (“Do Not Travel”) to China on February 2, 2020 by the U.S. Department of State. During this same time, travel to all other WHO regions remained fairly constant, followed by an abrupt reduction in March 2020. Notably, on March 11, 2020, COVID-19 was officially declared a pandemic by the World Health Organization (WHO), and most travel bans were implemented during this month.
This study is limited by utilizing one EHR for the follow-up on patient outcomes, as it is possible that the patients visited one of the few health centers in the region not using EPIC. Most patients in Iowa with COVID-19 in the early weeks of the epidemic would have been referred to UIHC so it unlikely a case in Iowa was missed. However, the travel clinic in the study draws patients from the neighboring state of Illinois, and it is possible that patients in that state would have visited a different hospital system or referral center. The dataset used for this study does not include state of residence. Additionally, the reason for travel (tourism, visiting friends and relatives, business, etc.) is not recorded in this dataset. It would have been interesting to see if the reasons for travel changed to any region as the pandemic developed, but that information was not available to the researchers.
It is apparent from the data that plans for travel decreased in the first few months of 2020. We are unable to compare this pattern to the same time in 2019, as the clinic opened for the first time in July of 2019. It is also possible that patients cancelled their previous planned travel during this time period, as more international travel warnings and restrictions were put into place. Data from the Transportation Security Administration (TSA) shows that airport traffic (measured in persons screened at security checkpoints in USA airports) remained stable until the second week of March 2020, when it rapidly decreased. If the patients previously seen in clinic cancelled their travel plans, then they would not site international travel as a cause for their exposure to COVID-19. Additionally, this would make them less likely to seek testing for COVID-19, which may further depress the low number of positive cases seen in the follow-up for this patient data set.