Vaccination in pregnancy study (VIPs) – studies of vaccine uptake, safety and effectiveness in mother and child

Research problem and specific questionsInfants are at risk of contracting severe respiratory infections such as whooping cough and infection with respiratory syncytial virus (RSV).

Vaccination of pregnant women induces a vaccine-specific immune response with the formation of antibodies that pass across the placenta to the fetus, thus protecting the child from potentially life-threatening infections.

We plan to investigate factors related to the uptake of pertussis and RSV vaccination in pregnancy, as well as the safety and effectiveness of the vaccines.Data and methodBy studying data from population-based national registers of all women who have given birth in Sweden since 2014 (>1 million mother-child pairs) with information on socio-economics, origin, vaccinations, diagnoses, medications, congenital malformations and deaths, we will study rare but serious side effects of the vaccines, their effectiveness and factors influencing vaccination uptake among pregnant women.

In order to increase knowledge and understanding of pregnant women´s reluctance and motivation for vaccination, individual interviews with vaccinated and unvaccinated pregnant women, as well as focus group discussions with healthcare professionals, who encounter these women, will be conducted.Societal relevance and utilizationVaccination during pregnancy can reduce and prevent severe illness and death in children.

At the same time, we know that vaccination uptake is influenced by socio-economic, cultural and regional factors, which can lead to unequal social conditions when it comes to the burden of disease. Further, pregnant women need to know that the vaccines are safe and effective.

In this project, we have a unique opportunity to use family- and population-based, as well as qualitative data to answer these questions and thus contribute to the maintenance of society´s trust in vaccinations, customize interventions to increase vaccination uptake and reduce the burden of disease in an equal way in society.Plan for project realizationThe epidemiological analyses regarding whooping cough, as well as the qualitative study will begin in 2025.

Data extraction for RSV studies will be initiated in 2025 and analyses will begin in 2026.

The costs for the project consist of data extraction from national registers, implementation of the qualitative study, salaries for the applicant, co-applicants, biostatistician, as well as for a doctoral student and a post-doc, who will be recruited in 2025.