What determines uptake of pertussis vaccine in pregnancy? A cross sectional survey in an ethnically diverse population of pregnant women in London
Introduction
Pertussis (whooping cough) is a highly contagious, acute bacterial infection of the respiratory tract caused by Bordetella pertussis. This exclusively human pathogen can affect people of all ages. Whilst adolescents and adults often display relatively mild symptoms, in unimmunised newborn infants the disease may run a severe course resulting in a high rate of complications and death [1], [2]. Pertussis persists as an infection of significant global public health importance leading to 126,000 deaths worldwide in children up to the age of 5 years in 2013 [3].
Fortunately, wide-scale childhood vaccination programmes have been influential in reducing the morbidity and mortality associated with pertussis [4], [5], [6], [7]. However, despite high vaccine coverage, a sharp increase in cases has been observed over the past decade [8], [9], [10], [11] in several countries in Europe, North America and Australia, most likely due to waning immunity after the introduction of the acellular pertussis vaccine [12]. In the UK, pertussis currently remains the most common cause of hospitalisation and deaths in infants from a vaccine-preventable disease [5], [13].
In late 2011 the UK witnessed a remarkable resurgence of confirmed pertussis cases to a level not seen for almost 20 years. By 2012, infected cases had risen tenfold and the outbreak was extending to infants too young to be protected through routine vaccination. Sadly, a total of 14 infant deaths were reported in England in that year. Consequently, an urgent review by the UK Joint Committee on Vaccination and Immunisation (JCVI) recommended to the Department of Health (DH) that pregnant women should be offered routine vaccination with a five component acellular-pertussis-containing vaccine, and this programme was initiated in October 2012, and was offered to all pregnant women between 28 and 38 weeks of pregnancy within the UK National Health Service (NHS) [14].
A subsequent Public Health communications campaign to inform women about the need for vaccination and to stimulate uptake ran for approximately 5 months, including publication of a range of printed materials, available on order. Communication with healthcare professionals used DH and NHS channels and relied upon Heads of Profession to convey key messages and clinical information about pertussis. The Primary Care Trusts (PCTs) were asked to establish vaccination services quickly using local GP Practices [15]. Vaccine stocks were delivered to GP practices and the hospital pharmacy held only a limited stock of vaccine for women who were long-term antenatal inpatients.
The intervention aims to minimise morbidity and prevent further infant deaths by boosting pre-existing maternal immunity and protect newborns indirectly via transplacentally transferred protective antibody, prior to receiving their own vaccines within the infant immunisation schedule. During the summer of 2014 the upper gestation recommended for receiving the vaccine was reduced to 32 weeks, in light of recent evidence [16] to ensure sufficient antibody transfer from mother to baby prior to birth.
Despite measures taken to promote pertussis vaccination, monthly figures published by Public Health England (PHE) since the start of the campaign have revealed varied vaccine uptake across England with London achieving 53.3% coverage at best in February 2013 [17].
In 2013 and 2014, a further 10 deaths in infants occurred with nine of these infants born to non-vaccinated mothers. In light of these data and the recent announcement that the vaccination programme will continue for a further five years [18], evaluation of the current pertussis vaccination programme in pregnancy is, therefore, timely and essential to inform the long-term strategy for optimising pertussis control.
We undertook a cross sectional survey to evaluate women's awareness, attitudes towards and acceptance of the current pertussis vaccination programme in order to identify potential barriers that could be addressed in order to improve implementation.
Section snippets
Study design
This study adopted qualitative and quantitative research techniques in the form of a cross-sectional questionnaire survey. Self-reported qualitative information on attitudes to vaccines and experiences was gained from the analysis of the free text.
Ethical considerations
Ethical approval was granted by the London-Hampstead Research Ethics Committee reference:13/LO/1712.
Theoretical framework and questionnaire development
A four part, anonymised questionnaire was developed based upon the Precaution Adoption Process Model and the Health Belief Model of health behaviour
Results
205 questionnaires were distributed to eligible women. Five questionnaires were excluded due to insufficient response to multiple questions. 200 were completed and analysed (97.0% response rate).
Discussion
Despite an ongoing public health campaign to promote pertussis vaccination during pregnancy in the UK and new cases in infants in the community, uptake has varied considerably across the country and has remained comparatively low in London.
We assessed the awareness and attitudes to pertussis vaccination in pregnancy using both quantitative and qualitative tools. Only 26.0% of women in our cohort had received the vaccine, considerably less than the 62.3% national coverage recently reported by
Author's contributions
The study was conceived by BK, BD and LR. The questionnaires were developed and implemented by BD and PJ with critical input from BH, LR and BK. The database was designed by BK and BL. The data entry and analysis of results was conducted by BD, PJ and BK. The first draft of the manuscript was developed by BD and BK and subsequent versions had input from all authors. The final submission has been approved by all authors. We affirm that the manuscript is an honest, accurate, and transparent
Competing interest statement
All authors declare that no support from any organisation for the submitted work has been received. There is no financial relationships with any organisations that might have an interest in the submitted work, and no other relationships or activities that could appear to have influenced the submitted work.
Funding
This study was funded by a grant from the Imperial College Biomedical Research Centre to BK. BK is also supported by a programme grant from the MRC (MC_UP_A900/1122). The research was conducted independently from its funders.
Acknowledgements
We acknowledge the Midwives and Obstetricians in the antenatal clinics who facilitated recruitment and thank all of the pregnant women who filled in the questionnaires.
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