Was holiday travel in August or September 2020 associated with higher diagnosis of COVID-19?

This study is a cross-sectional study that examined the association between holiday travel and the diagnosis of COVID-19 infection using the results of an internet survey conducted from October 27 to November 6, 2020. In this survey, we asked whether or not respondents traveled for one night or more in August or September 2020 (including traveling to visit family and not including business trips), whether they had been infected and then diagnosed with COVID-19 at a medical institution, and other background information. We performed multivariate logistic regression analysis with the primary outcome of diagnosis of COVID-19 infection. The responses of 16,642 people were used for the analysis. The analysis showed a significant positive association between traveling in August or September and the diagnosis of COVID-19 infection. In the secondary analyses, the association between traveling in August and September and the experience of each one of seven symptoms (fever, cough, sore throat, fatigue, shortness of breath, taste / smell disorders, diarrhea) in the previous month were explored using multivariate logistic regressions. The analyses showed positive associations between each of the symptoms and going to travel except for symptoms of cough. There are various limitations to this study, and great care must be taken in interpreting the results.