IL2RG and infection: Similar to immunocompetent Syrian hamsters, following infection with 5 × 104 ID50 (high dose; 105 TCID50) of SARS-CoV-2, four (2 males, 2 females) IL2RG KO hamsters lost approximately 5-10% of their body weight over the first 5 days following infection before recovering (Figure 7(A)).