Do Previously Held Vaccine Attitudes Dictate the Extent and Influence of Vaccine Information-Seeking Behavior during Pregnancy?

"Vaccine information-seeking behavior was found to play a complex role in the vaccine decision-making process."

Vaccine information-seeking behaviour is present in a sizable minority of both individuals who accept but also those who decline vaccination. Pregnancy, in particular, represents a high information need state, where uncertainty around medical interventions like vaccines is common. This study investigated vaccine information-seeking behaviour over the course of the pregnancy vaccination decision-making process in the context of pertussis vaccination in the United Kingdom (UK).

The variables of vaccine confidence and risk perception of vaccination during pregnancy were measured across 2 questions, which 182 British women completed. Questionnaire T1 gathered responses from women early in their pregnancy (between 4 and 18 weeks of their pregnancy) - before the decision to vaccinate for pertussis is usually prompted by a healthcare professional. Questionnaire T2 gathered information from the same women after they made their decision (after 36th week of their pregnancy). Additional variables of decision conflict and intention to vaccinate were recorded during early pregnancy, while vaccine information-seeking behaviour and vaccine uptake were recorded during late pregnancy.

At Questionnaire T1, 94.5% of participants were aware of the pertussis vaccination programme during pregnancy; when re-contacted for Questionnaire T2, 89.6% reported having received the vaccine (compared to the national rate of 71.9%).

88.8% of participants reported seeking additional information about the pertussis vaccine during pregnancy, with 62% stating that seeking information from a healthcare professional influenced them towards vaccination. When information was sought out from friends and family members, participants largely reported no influence (68.4%). According to the researchers, this could indicate that either the information gained was not used to inform the decision-making process, or it confirmed pre-existing beliefs and therefore did not move the participant in one direction or the other. As for the internet, while this channel is often cited as a detriment to vaccine uptake, the information sought through the internet tended to point participants towards vaccination (57% influencing towards compared to 7% influencing away from vaccination). "This finding likely indicates the positive effects of having a strong evidence-based web presence such as that of the NHS [National Health Service] in the UK."

The researchers performed multiple linear regressions to test:

• If the variables of vaccine confidence, risk perception of vaccination during pregnancy, decision conflict, and intention to vaccinate predicted the total number of hours of vaccine information-seeking behaviour. The variables significantly predicted the total number of hours of vaccine information-seeking behaviour and successfully explained 11.0% of the variance in vaccine information-seeking behaviour. Women who had a lower confidence in vaccination (p = .004) and those who saw the risk of pertussis disease as high compared to the risk of side effects from the pertussis vaccination during pregnancy (p = .004) spent significantly more time seeking information about the pertussis vaccination.
• If the variables of vaccine confidence (T1), risk perception of vaccination during pregnancy (T1), decision conflict, and intention to vaccinate predicted the perceived strength and direction of influence of information found through seeking. Only participants who had reported seeking information were included in this analysis (n = 161). The variables significantly predicted the perceived strength and direction of influence of information found through seeking and successfully explained 6.5% of the variance. One variable, intention to vaccinate, was found to be a significant predictor (p = .011) and indicated that the greater the level of intention to vaccinate at T1 the more likely the participant was to perceive the information they found as pointing them towards vaccination.
• If the variables of risk perception of vaccination during pregnancy, vaccine confidence, vaccine information-seeking behaviour, intention to vaccinate, and strength of recommendation from a healthcare professional predicted vaccine uptake. The model accounted for between 27.6% and 64.1% of the variance in vaccine uptake, with 99.4% of vaccinating participates predicted and 71.4% of non-vaccinating participants predicted. One variable, vaccine confidence, significantly predicted vaccine uptake.
• If the variables of vaccine uptake, total hours of vaccine information-seeking behaviour, and strength of recommendation significantly predicted the difference in risk perception of vaccination during pregnancy. The variables did not significantly predict the difference. But it was found that women's perception of risk related to vaccination during pregnancy significantly changed throughout the pregnancy, with women perceiving the risk of pertussis disease higher as compared to the risk of side effects from the vaccine as the pregnancy progresses.

The researchers reflect on the fact that higher intention to vaccinate was associated with finding information that was perceived as pointing participants towards vaccination, and lower intention to vaccinate was associated with finding information that was perceived as pointing participants away from vaccination. "This form of search behavior appears to be akin to the confirmation bias whereby evidence is reviewed in such a way so as to support pre-existing beliefs and expectations."

Practical implications for vaccine communication:

1. Spending additional time seeking information about vaccination outside of the healthcare professional relationship does not appear to have a negative effect on vaccine uptake. The exception could be with individuals who indicate a particularly low intention to vaccinate, whereby internet information seeking could potentially move them more away from vaccination; additional time with a healthcare professional may help address their concerns.
2. With the positive shift in risk perception surrounding the pertussis vaccine occurring over the course of a pregnancy if women decide earlier in the pregnancy not to get the vaccine, recommending it again later in the pregnancy may yield a different result.
3. Pregnancy vaccinations may be a good time to also provide information pertaining to childhood vaccinations. Considering that a high proportion of women are active in the information gathering process, guidance on appropriate sources of information at this stage could be beneficial.