ABSTRACT
The U.S. Secretary of Health and Human Services declared a public health emergency in the U.S. on 31 January 2020 in response to the spread of coronavirus disease 2019 (COVID-19). On 20 March 2020, the President of the U.S. proclaimed that the COVID-19 outbreak in the U.S. constituted a national emergency, retroactive to 1 March 2020. Between 1 January and 30 September 2020, a total of 53,048 Military Health System (MHS) beneficiaries were identified as confirmed or probable cases of COVID-19 infection. The majority of cases were male (69.1%) and 45.4% were aged 20-29 years. The demographic and clinical characteristics of these cases varied by beneficiary type (active component service members, recruits, Reserve/Guard, dependents, retirees, and cadets). Of the total cases, 35.8% had been diagnosed with at least 1 of the comorbidities of interest, and 20.0% had been diagnosed with 2 or more comorbidities. The most common comorbidities present in COVID-19 cases were any cardiovascular diseases(12.7%), obesity or overweight (11.1%), metabolic diseases (10.5%), hypertension (9.9%), neoplasms (7.9%), any lung diseases (7.5%), substance use disorders, including nicotine dependence (5.4%), and asthma (3.2%). There were a total of 1,803 hospitalizations (3.4%) and 84 deaths (0.2%).