Using an Administrative and Clinical Database to Determine the Early Spread of COVID-19 at the US Department of Veterans Affairs during the Beginning of the 2019-2020 Flu Season: A Retrospective Longitudinal Study.

Lilia R Lukowsky,William Neil Steers,Aram Dobalian,Kiran S Kamble,Claudia Der-Martirosian

doi:10.3390/v14020200

Lilia R Lukowsky, William Neil Steers + Show 3 more

Open Access

https://doi.org/10.3390/v14020200

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Abstract

Background. Previous studies examining the early spread of COVID-19 have used influenza-like illnesses (ILIs) to determine the early spread of COVID-19. We used COVID-19 case definition to identify COVID-like symptoms (CLS) independently of other influenza-like illnesses (ILIs). Methods. Using data from Emergency Department (ED) visits at VA Medical Centers in CA, TX, and FL, we compared weekly rates of CLS, ILIs, and non-influenza ILIs encounters during five consecutive flu seasons (2015–2020) and estimated the risk of developing each illness during the first 23 weeks of the 2019–2020 season compared to previous seasons. Results. Patients with CLS were significantly more likely to visit the ED during the first 23 weeks of the 2019–2020 compared to prior seasons, while ED visits for influenza and non-influenza ILIs did not differ substantially. Adjusted CLS risk was significantly lower for all seasons relative to the 2019–2020 season: RR15–16 = 0.72, 0.75, 0.72; RR16–17 = 0.81, 0.77, 0.79; RR17–18 = 0.80, 0.89, 0.83; RR18–19 = 0.82, 0.96, 0.81, in CA, TX, and FL, respectively. Conclusions. The observed increase in ED visits for CLS indicates the likely spread of COVID-19 in the US earlier than previously reported. VA data could potentially help identify emerging infectious diseases and supplement existing syndromic surveillance systems.

Highlights

Evidence suggests that COVID-19 might have been present in China [1,2], Europe [3,4,5,6,7,8]and in the United States (US) [9,10,11] much earlier than 20 January 2020 when the firstCOVID-19 case [9], or January 30 when the first person-to-person transmission were reported in the US [12]
Compared to the 2019–2020 season, we found that the unadjusted rates for COVID-like symptoms (CLS)
We modeled CLS, influenza, and non-influenza influenzalike illnesses (ILIs) separately, which allowed us to observe consistent increases in CLS, but not in the rest of ILI, indicating that the increase in Emergency Department (ED) visits during early 2019–2020 was likely to have been due to COVID-19

Summary

Introduction

Evidence suggests that COVID-19 might have been present in China [1,2], Europe [3,4,5,6,7,8]and in the United States (US) [9,10,11] much earlier than 20 January 2020 when the firstCOVID-19 case [9], or January 30 when the first person-to-person transmission were reported in the US [12]. Because patients with COVID-19 often experience symptoms resembling ILI, it is important to differentiate between ED visits for influenza and non-Influenza-Like illnesses and encounters for possible COVID-19 infections. It is especially important as US Veterans tend to be older, have a higher number of comorbidities, lower incomes, and are more likely to be from racial and ethnic minorities compared to the general adult population [19,20] Unlike prior studies, we used the established case definition for COVID-19 [21] in the absence of laboratory tests. VA data could potentially help identify emerging infectious diseases and supplement existing syndromic surveillance systems

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Conclusion