In this special issue, available in the GAIA outputs section of this website, the next set of 11 case definitions including five obstetric outcomes (abortion, antenatal bleeding, gestational diabetes, dysfunctional labour, foetal growth retardation) and six neonatal outcomes (low birth weight, small for gestational age, neonatal encephalopathy, respiratory distress, failure to thrive and microcephaly) developed in the framework of the GAIA project are published. The definitions have been the result of the collaborative work of a global functional network of experts including experts in vaccinology, maternal health, and neonatology from academia, public health institutes, regulatory agencies, investigators and vaccine manufacturers from LMIC and high-income countries.

The 11 standardized case definitions of prioritized obstetric and neonatal outcomes included in this issue have been developed following the standard Brighton Collaboration process. The first 10 definitions were published in a special issue of the journal Vaccine in December 2016. All 21 definitions have been complemented with definitions and assessment algorithms of enabling terms.

Furthermore, and in the light of the important public health benefit of immunization in pregnancy in particularly LMIC and the significant challenges of conducting research in low resource settings especially with pregnant women, the issue includes a paper by Kochhar et al. highlighting pertinent aspects of study design, regulatory and safety monitoring considerations in these settings.