Prevalence and predictors of maternal seasonal influenza vaccination in Hong Kong

Abstract

Pregnant women infected with influenza virus are more likely to experience severe complications compared with their non-pregnant peers. Yet influenza vaccine uptake is low among pregnant women. The purpose of this study was to assess the prevalence and predictors of seasonal influenza vaccine uptake among pregnant women in Hong Kong.

Using a multi-centre cross-sectional design, we recruited 2,822 new mothers during their immediate postpartum stay at all eight public obstetric hospitals over a three-month period from April through June 2011. We assessed their antenatal maternal influenza vaccination status as well as health beliefs and perceptions toward influenza and influenza vaccination. Bivariable and multivariable logistic regression was used to identify the predictors of vaccination uptake. Only 49 (1.7%; 95% CI 1.3% to 2.3%) participants were vaccinated during pregnancy. Fears that the vaccine would harm their foetuses or themselves were the most common reasons for not being vaccinated. Being aware of vaccination recommendations (OR=2.69; 95% CI 1.06, 6.82), being advised by a health care provider (HCP) to be vaccinated (OR=6.30; 95% CI 3.19, 12.46), a history of influenza vaccination (OR=2.47; 95% CI 1.25, 4.91), perceived susceptibility to influenza infection (OR=3.67; 95% CI 1.64, 8.22), and perceived benefits of influenza vaccination (OR=9.98; 95% CI 3.79, 26.24) were all independently associated with vaccination. Perceived barriers to vaccination (OR=0.17; 95% CI 0.07, 0.40) were strongly associated with failure to vaccinate.

A qualitative descriptive design was also used to explore a broad spectrum of health knowledge and beliefs of participants regarding influenza infection and influenza vaccination during pregnancy. An interview guide was developed based on the Health Belief Model. A sub-sample of participants who completed the quantitative study were invited to take part in the qualitative interviews. A total of 32 postpartum women were interviewed and only two had been vaccinated during pregnancy. Following thematic analysis, three themes emerged that further highlighted the pregnant women’s perceptions toward influenza vaccine and their decision-making process, perceived risk of influenza infection, perceived risk of an influenza vaccine, and decision-making cues.

Overall, participants held negative impressions about influenza vaccination during pregnancy. This could be because of misconceptions and underestimation of the threats of influenza infection to themselves and their foetuses. They were also confused about the safety and efficacy of the influenza vaccine. Participants were confused about the differences between preventive strategies and treatment for influenza and HCPs did not offer or recommend vaccination. Because of negative media reports about the pros and cons of vaccination, participants were hesitant to receive the vaccine. Nevertheless, findings suggested that motivating forces for vaccine acceptance were a high prevalence of circulating influenza infection during their pregnancy and HCP recommendations and reassurances that the vaccination was safe, effective, and beneficial for the foetus. Vaccination promotion strategies need to focus on encouraging HCPs to discuss vaccination with their pregnant clients and provide accurate and unbiased information about the risks of influenza infection and the benefits of vaccination.