Zaman K, et al. - Researchers investigated the effect of two dosed of monovalent type 2 oral poliovirus vaccine (mOPV2) on the type 2 immune response by varying the time interval between mOPV2 doses and inactivated poliovirus vaccine (IPV) co-administration with mOPV2 in a randomised, controlled, parallel, open-label, non-inferiority, inequality trial at two study clinics in Dhaka, Bangladesh. Between Dec 7, 2015, and Jan 5, 2016, 760 infants were randomly assigned to receive two mOPV2 doses at intervals of 1 week (n=191), 2 weeks (n=191), 4 weeks (n=188), or 4 weeks plus IPV (n=190). Outcomes suggested that administration of mOPV2 at short intervals does not interfere with its immunogenicity. Poliovirus type 2 immune response was not enhanced by the addition of IPV to the first mOPV2 dose.