A Mother's Dilemma: The 5-P Model for Vaccine Decision-Making in Pregnancy

"[V]accination during pregnancy is a complex decision. Unique pregnancy-specific factors must be considered in addition to other factors applicable to the general population in understanding the decision-making process."

When it comes to vaccinations, pregnant women have a more complex decision-making process that generally involves balancing risks and benefits for themselves and the fetus. The United States Centers for Disease Control and Prevention (CDC) recommends that pregnant women receive vaccines for pertussis, tetanus, diphtheria, polio, influenza, and COVID-19. Despite these recommendations, many pregnant individuals are highly vaccine hesitant due to safety concerns regarding vaccines, lack of information on vaccines from care providers, perceived lack of data on the safety of vaccines, and low self-perceived risk of infection or severity of illness. The objective of this paper is to highlight the challenges of vaccine decision-making in pregnancy and to present a vaccine-acceptance model that can be used to inform public health campaigns and provider-patient interactions.

Vaccine hesitancy can be generally divided into structural and attitudinal barriers, with the latter playing a larger role in why pregnant individuals have greater vaccine hesitancy. In addition to pregnancy-specific and other attitudinal barriers to vaccination in pregnancy, there are structural barriers to vaccination (e.g., access, affordability, trust in science), which are addressed in many vaccine-acceptance models designed for the general population.

As reported here, to date, there have been no specific models for vaccine acceptance in pregnancy, but several constructs that explain factors informing vaccine hesitancy and acceptance exist; many of these models build upon the Health Belief Model (HBM). The HBM is divided into these categories: perceived susceptibility to the disease, perceived severity of the disease, perceived benefits of the disease-prevention behaviour, barriers to the disease-prevention behaviour, a cue to action, and self-efficacy.  In 2014, a new vaccine-decision-making model was proposed, called the 3C model. The 3C model describes three factors of vaccine hesitancy: confidence, complacency, and convenience. This model was expanded in 2015 in the 4C model to include a utility calculation, where the benefits of the vaccine play a larger role. In 2016, the 5A model was developed, in which vaccine acceptance was described in terms of access, affordability, awareness, acceptance, and activation.

Although there are no specific models for vaccine acceptance in pregnancy, a model has been proposed to describe decision-making in pregnancy that may be applied to vaccine acceptance. This model describes three themes in the decisions of pregnant people: uncertainty, bodily autonomy, and being a good mother. These three themes are interlinked with three actions: information gathering, balancing aspects of a choice, and aligning with a birth philosophy.

Based on this prior scholarship and the researchers' clinical experience (and with their One Vax Two Lives social media campaign), they propose a 5-P model of vaccine acceptance in pregnancy that combines features of the HBM and a pregnancy decision-making model. It incorporates the following key factors: (i) perceived information sufficiency regarding vaccination risks during pregnancy, (ii) harm avoidance to protect the fetus, (iii) relationship with a healthcare provider, (iv) perceived benefits of vaccination, and (v) perceived disease susceptibility and severity during pregnancy. The factors defining the 5-P model exist within a background of social determinants of health, including proficiency in the native language, geographic location (country, state, neighborhood), education, healthcare access, structural barriers to vaccination, religion, and culture. Historical events also play a role in determining an individual's underlying trust in medicine, including medical racism and the exclusion of pregnant individuals from vaccine trials. Finally, the pregnant individual must weigh the pros and cons of all these factors for herself and the fetus, resulting in a complex decision-making process.

Among the research gaps that could help strengthen the model's applicability in practice: Research on vaccine hesitancy should be conducted broadly among minority and other groups that have been historically harmed or marginalised by medicine and science. Research should also be conducted to learn about the reaction of pregnant individuals to social media ads and other public health materials to determine the best method of addressing pregnant women's unique sources of vaccine hesitancy.

In conclusion: "The 5-P model is an important beginning for further research into the factors that lead to vaccine hesitancy or acceptance in pregnancy."