In an effort to generate a better neonatal mouse model of RSV infection, we show here that neonatal mice infected with the chimeric rA2-19F strain of RSV, compared to the standard A2 strain, exhibited enhanced lung pathology, including interstitial pneumonitis and alveolitis, enhanced Th2 responses, and reduced effector CD8+ T cells during both primary and secondary infections. Here, CD8A is linked to infection.