Universal latent (50-90% adults seropositive); 大多 asymptomatic; immunocompromise: retinitis (HIV CD4 < 50), pneumonia/colitis (transplant), congenital (#1 infectious cause of birth defects 全球); letermovir prophylaxis HSCT 2017 + maribavir refractory 2021 = 22E 變革。