Why are around a third of pregnant women not vaccinated against whooping cough?

Whooping cough is widespread, highly contagious and serious for new-born babies. However, 30 per cent of pregnant women in the UK do not receive the whooping cough vaccine, leading to avoidable illness and death and the Covid-19 pandemic appears to be having a negative impact on these numbers. New research led by the University of Bristol aims to understand why pregnant women are not being vaccinated against whooping cough and how to improve delivery by maternity services and mothers’ uptake of vaccines.

Pregnant women are vaccinated against whooping cough to protect babies from birth until they are old enough for their own vaccination. The pregnancy vaccine is safe and effective, estimated to prevent at least six deaths and 165 hospitalisations in babies, as well as preventing 2,050 mothers becoming ill with whooping cough each year.

The vaccine is now offered at the same time as the 20-week ultrasound scan to make it more accessible for women. Unfortunately, vaccination rates are highly variable across the country and women from ethnic minority backgrounds are less likely to be vaccinated. However, the reasons for these inequalities are unknown.

Dr Emma Anderson, Research Fellow and Health Psychologist in the Bristol Medical School: Population Health Sciences (PHS), who is leading the study, said: “According to the World Health Organisation, vaccine hesitancy is a top ten global health threat. We do not know if mothers who are not vaccinated in pregnancy are less likely to vaccinate their children. Improving pregnancy vaccination rates may increase child vaccine rates.

“I hope this research will help increase the number of pregnant women receiving the whooping cough vaccine and inform other mother and child vaccine programmes. Finding ways to maximise the effectiveness of vaccination programmes is even more important in the wake of Covid-19. Tackling inequality is vital so that everyone can be protected.”

The National Institute for Health Research (NIHR)-funded research will examine national GP records to see what characteristics (such as ethnicity, age, first child, location) could predict whether a pregnant woman is vaccinated and then link mothers’ and children’s records to investigate the relationship between rates of vaccination in mothers and their children.

The study will use a mixed methods approach to identify barriers and facilitators to the delivery of the whooping cough vaccine in maternity services and the barriers and facilitators to uptake of the vaccine in women.

Working with a clinical advisory group and a patient and public involvement (PPI) group, questionnaires will be designed to explore practical barriers and attitudes to vaccines, drawing on well-established theories about what influences behaviour.

Healthcare professionals from England’s highest and lowest vaccinating NHS areas will be invited to complete the healthcare professional questionnaire online and take part in additional interviews. The data will be analysed to identify reasons for differences between high and low vaccinating areas in the UK to identify procedures for change.

Women who have recently had a baby will be invited to complete the patient questionnaire online and take part in additional interviews. Using GP records, women who did and did not receive their whooping cough vaccination will be invited to take part by their GP surgery. Data analysis will identify the importance of vaccine hesitancy, practical and communication barriers and ways for change.

Finally, using well established methods for designing interventions and working with clinical and patient advisory groups, Dr Anderson will produce recommendations to help increase the number of pregnant women receiving the whooping cough vaccine and to inform other mother and child vaccine programmes.

Patient and public involvement (PPI) will be ongoing during the project to help design the research and interpret findings.

The research project ‘MAternal Vaccination In the NHS (MAVIS) Study: A mixed methods approach to improving antenatal immunisation rates, focusing on pertussis’ started this month (January 2021).