Pedersen O, Herskind AM, Kamper J, Nielsen JP, Kristensen K. Rehospitalization for respiratory syncytial virus infection in infants with extremely low gestational age or birthweight in Denmark. Acta Paediatr 2003; 92: 240-242. Stockholm. ISSN 0803-5253 Aim: To determine the risk of rehospitalization for respiratory syncytial virus (RSV) infection during the first 2 y of life in extremely preterm infants. Methods: Records on all rehospitalizations during the first 2 living years of all infants born with gestational age <28 wk or birthweight <1000 g during 1994 and 1995 in Denmark were retrospectively reviewed. Results: Among 240 eligible infants, 43 (18%) had been rehospitalized 48 times owing to RSV. In infants (n = 210) without CLD the risk of rehospitalization for RSV was 16%, whereas in infants with CLD (n = 30) it was 30% ( p = 0.065). Eighteen infants (38%) required respiratory support (supplemental oxygen only 3, continuous positive airway pressure 14, mechanical ventilation 1). Apart from CLD the only factor that could be associated with increased risk of hospitalization for RSV was discharge during autumn ( p = 0.05). No infant died from RSV infection. Conclusion:The high rate of rehospitalization for RSV in extremely preterm infants in Denmark, especially in infants with CLD, should lead to considerations concerning more widespread use of prophylaxis against RSV in these infants.