In a study involving over 2000 children in Thailand and the Philippines, Forrest et al. reported that after receiving two-doses of LAIV, HAI-seronegative children that had ≥100 spot-forming unit (SFU)/106 PBMC in an IFN-γ-ELISPOT assay (using inactivated vaccine components as antigens) were protected against symptomatic disease during subsequent infection [77]. The gene discussed is IFNG; the disease is infection.