Assessing the interactions between COVID-19 and influenza in the United States

Casey M Zipfel; Shweta Bansal

We suggest that the link between increased risk perception and decreased disease transmission is heightened protective behaviors through non-pharmaceutical interventions (NPIs). This conjecture is supported by past studies that have shown that risk perception is a strong predictor of preventative health behaviors [21] . However, the timing of this e↵ect (early to mid February) is important to consider. The decrease in the observed US ILI peak occurred before widespread closures of public spaces and implementation of social distancing to mitigate COVID-19 transmission. Our results could indicate that the use of personal NPIs such as handwashing and voluntary social distancing may have been occurring before policy changes took place in March 2020. In a survey conducted in early February 2020, US respondents rated their risk perception of COVID-19 as a median score of 5 out of 10, and more than 90% of participants were aware of infection prevention measures [22] . Our mechanistic model suggests that an average of 5% reduction in transmission likelihood could result in the ILI dynamics observed of the 2019-2020 season. Past studies have shown that frequent, e↵ective handwashing can result in a comparable moderate reduction in infections [23, 24, 25] . A meta-analysis of the e↵ects of NPIs in reducing influenza transmission demonstrated that hand hygiene was significant in reducing influenza transmission, with an odds ratio of 0.62 [26] .