• 18-79 years old

• Have a history of any of the following risk factors for severe COVID:

‣ Asthma

⁃ Physical inactivity (defined as \<150 mins of moderate activity per week or \<75 mins of vigorous activity per week)

⁃ HIV with CD4 count ≥ 500 cells/ul

⁃ Current or prior smoker

⁃ Depression or other mood disorder

⁃ Schizophrenia spectrum disorder

⁃ Cerebrovascular disease

⁃ Heart failure

⁃ Coronary artery disease

⁃ Cardiomyopathy

⁃ Pulmonary embolism

⁃ Pulmonary hypertension

⁃ Cystic fibrosis

⁃ Bronchiectasis

⁃ Chronic obstructive pulmonary disease

⁃ Interstitial Lung Disease

⁃ Stage I or II chronic kidney disease

⁃ Stage 1 defined as normal GFR (\> 90) but with other signs of kidney damage such as proteinuria or hematuria

⁃ Stage 2 defined as having a glomerular filtration rate (GFR) of 60 - 89 ml/min/1.73m2

⁃ Gestational diabetes

⁃ Type 1 diabetes with most recent HgbA1C \< 7.5%

⁃ Obesity with BMI ≥ 30 and \< 40

⁃ Liver disease without cirrhosis and with liver enzyme levels

⁃ (AST and ALT) no greater than three times the upper limit of normal

• Military Health System beneficiary and DEERS eligible

• Willing to be randomized to receive either the Novavax COVID-19 vaccine or the mRNA Pfizer-BioNTech COVID-19 vaccine

• Will be able to return for a clinic visit in approximately 30 days and be able to follow-up online for the next 9 months.