Coverage and determinants of influenza vaccine among pregnant women: a cross-sectional study

Abstract

Background: Pregnant women are at increased risk of influenza-related complications. The World Health Organisation recommends influenza vaccination to this high-risk population as highest priority. However, achieving high influenza vaccine coverage among pregnant women remains challenging. We conducted a cross-sectional survey to estimate the coverage and determinants of influenza vaccination among pregnant women in Singapore.

Methods: Between September and November 2017, pregnant women aged ≥21 years were recruited at two public hospitals in Singapore. Participants completed an anonymous, self-administered online questionnaire assessing participants' influenza vaccination uptake, knowledge of and attitudes towards influenza and the influenza vaccine, vaccination history, willingness to pay for the influenza vaccine, and external cues to vaccination. We estimated vaccine coverage and used multivariable Poisson models to identify factors associated with vaccine uptake.

Results: Response rate was 61% (500/814). Only 49 women (9.8, 95% Confidence Interval (CI): 7.3-12.7%) reported receiving the vaccine during their current pregnancy. A few misconceptions were identified among participants, such as the belief that influenza can be treated with antibiotics. The most frequent reason for not being vaccinated was lack of recommendation. Women who were personally advised to get vaccinated against influenza during pregnancy were 7 times more likely to be vaccinated (prevalence ratio (PR) = 7.11; 95% CI: 3.92-12.90). However, only 12% of women were personally advised to get vaccinated. Other factors associated with vaccine uptake were vaccination during a previous pregnancy (PR = 2.51; 95% CI: 1.54-4.11), having insurance to cover the cost of the vaccine (PR = 2.32; 95% CI: 1.43-3.76), and higher vaccine confidence (PR = 1.62; 95% CI: 1.30-2.01).

Conclusions: Influenza vaccination uptake among pregnant women in Singapore is low. There is considerable scope for improving vaccination coverage in this high-risk population through vaccination recommendations from healthcare professionals, and public communication targeting common misconceptions about influenza and influenza vaccines.

Keywords: Influenza; Influenza vaccine; Maternal vaccination; Pregnancy; Vaccine recommendation.

Fig. 1

Conceptual framework. Factors contributing to participants being vaccinated against influenza during current pregnancy; for variables under each domain, see Additional file 1 Tables S4 and S5

Fig. 2

Recruitment chart. SGH: Singapore General Hospital; KKH: KK Women’s and Children Hospital

Fig. 3

Willingness to vaccinate. Willingness to vaccinate under different scenarios (x-axis), by current willingness to vaccinate during pregnancy (y-axis). Darker colours indicate greater willingness than currently to vaccinate against influenza during pregnancy under the scenarios presented. Numbers in boxes represent respondent mean scores on a 5-point scale (1 = Very unlikely; 2 = Unlikely; 3 = Neutral; 4 = Likely; 5 = Very likely). The bar chart on the right denotes the distribution of respondents by category of current willingness to vaccinate