This study will establish the duration of excretion of rotavirus vaccine in stool following vaccination of premature babies hospitalised in a neonatal unit at the time of vaccination.

Rotavirus is the commonest cause of severe gastroenteritis in young children, and premature babies are at high risk of serious disease. The RV1 rotavirus vaccine is an altered form of the virus and is given to all children at 8 weeks and 12 weeks of age in the UK. It is given by mouth and excreted in the stool following vaccination - the vaccine virus can therefore be transmitted between people in the same way as the normal virus. Premature babies often receive their initial vaccines while they are still hospitalised in neonatal units. There are no data regarding stool excretion of the RV1 rotavirus vaccine in premature babies - there is a theoretical risk of transmission of the vaccine virus to other babies in the unit (if there was inadequate staff hand washing). Some countries have therefore advised against immunisation of babies while in the neonatal unit. In the UK, however, the vaccine is being given in neonatal units, enabling evaluation of the vaccine in hospitalised premature babies.

This is an observational study of babies admitted to the neonatal unit at the John Radcliffe Hospital, Oxford University Hospitals NHS Trust who receive their first dose of rotavirus vaccine during their hospital stay.

Inclusion Criteria:

• Participant's parent is willing and able to give informed consent for participation in the study.
• Current inpatient in the neonatal unit and expected to remain an inpatient for at least 14 days following immunisation with rotavirus vaccine.
• Due to receive rotavirus vaccination during their admission.
• Born at less than 37 completed weeks gestation (i.e. up to and including 36 weeks and 6 days)

Exclusion Criteria:

• Parent is listed on the study delegation log.

Premature babies receiving their first dose of rotavirus vaccine while an inpatient on the neonatal unit at the John Radcliffe Hospital, Oxford University Hospitals NHS Trust