? Background: Maternal immunization is an effective and safe strategy in preventing and reducing morbidity and mortality associated with infectious diseases in pregnant women and newborns . However, despite global efforts, maternal vaccination coverage, except for maternal tetanus vaccination, is still suboptimal in most high-income countries, and maternal immunization programs are scarce or inexistent in most low and middle-income countries. In Spain, coverage of the pertussis vaccine in pregnant women in 2018 reached 82.7%, translating into a substantial impact on reduction of incidence of pertussis, especially in infants under three months of life, which declined from 17.99 to 8.80 cases per 100.000 inhabitants/year. However, in the same period, coverage of the influenza vaccine in pregnancy across the country was below 30%. Insights into the underlying disease and target population (mothers and/or infants) that is to be protected, it appears that healthcare providers play a role in maternal vaccine uptake, as well as communication strategies and immunization training. Understanding baseline awareness and perceived risk and benefits of maternal immunization among pregnant women and health care providers is essential to better anticipate acceptance and successful delivery of maternal immunization strategies. This study is expected to provide the information needed to guide decisions and approaches for effective maternal immunization that prevents morbidity and mortality from infectious diseases in mothers and their babies.
? Objectives: The GENERAL OBJECTIVE of this study is to gain understanding of the potential barrier and facilitators to maternal vaccine acceptance in order to achieve wide implementation and uptake of future new vaccines given in pregnancy.
? Methods: To accomplish the study objectives, we will conduct a mixed-methods study. This approach will include two different methodologies to complementary answer the research objectives. Those are detailed as sub-studies.
? Sub-study 1 will have a quantitative design based on a cross-sectional survey study. The survey will cover determinants of vaccine hesitancy and will include constructs related to knowledge, attitudes, beliefs, and practices regarding maternal vaccination at a specific point in time.
? Sub-study 2 will have a qualitative design based on Phenomenology. Phenomenology is an approach to understand first-hand experiences of those involved in a phenomenon of interest to the research question.
? Study population and setting of SUB-STUDY 1: This study will be conducted with women attending the Maternity department of HCB, which covers a population of more than 1.500.000 inhabitants. The target population will be 300 pregnant women attending routine ANC, and 300 healthcare providers (gynecologists, midwives, pediatricians and general practitioners) working at the Maternity of HCB, at centers of the Sexual and Reproductive Healthcare network (ASSIR, for the Catalan acronym), and at Primary Care Centers (CAPs) of the health area of HCB.
? Study population and setting of SUB-STUDY 2: Any pregnant women, at any gestational age, attending the HCB, or any ASSIR network centers willing to be anonymously interviewed and audio-recorded. We aimed to interview 20 pregnant women and 10 healthcare professionals. The possibility to broaden the sample size will be considered in case the saturation point was not reached. If data saturation is not achieved, and discussed topics deserve further exploration, additional SSIs will be conducted.
? Ethical considerations: The study will be conducted in accordance with the Good Clinical Practice Guidelines, the Declaration of Helsinki, and local rules and regulations. The involvement of human subjects and the use of identifiable data from the subjects recruited in the study will be treated according to ethical principles. An informed consent will be developed for participants to read it and sign it before enrolling in the study, or to give consent orally. Participation in the study will be voluntary, and confidential. The anonymity of the personal data of the participants will be preserved by coding them with IDs. The plan will be carefully designed to safeguard the confidentiality of the participants, as well as answer the research questions.