All animal procedures were performed by following the Institutional Animal Care and Use Committee (IACUC) guidelines of the Icahn School of Medicine at Mount Sinai IACUC and according to an approved protocol. Six- to 8-week-old female, BALB/c mice were vaccinated via the intramuscular route with 3 μg of each respective protein with 1:1 mixture of Addavax (InvivoGen) in a total volume of 50 μL. After 3 weeks, mice were bled and vaccinated with the same protein as used for the initial vaccination. After 3 weeks, mice were administered anesthesia via the intraperitoneal route and intranasally transduced with AdV-hACE2 at 2.5 × 108 PFU per mouse (21 (link)). Anesthesia was prepared using 0.15 mg/kg of body weight ketamine and 0.03 mg/kg xylazine in water. Five days later, all mice were infected with authentic wild-type SARS-CoV-2 intranasally with 1 × 105 PFU. Mice were humanely euthanized on day 3 and day 5 for assessment of virus in the lungs. Lungs were homogenized using a BeadBlaster 24 (Benchmark) homogenizer (46 (link)– (link)48 (link)). Viral load in the lung was quantified via a classic plaque assay (49 (link), 50 (link)). For mice that also received mRNA-LNP vaccine, the vaccine was administered via the intramuscular route and each mouse was immunized with a single dose of 3 μg of mRNA-LNP.