Is there a need for a whooping cough booster for older children?

A new study at Oxford University has looked at rates of pertussis (whooping cough) infection in school age children, and asks the question: would a pertussis booster for older children improve protection for vulnerable groups in the population?

Pertussis is a serious infectious disease that can be life-threatening, especially for young babies. In the UK, babies and children currently receive four doses of pertussis vaccine to protect against the disease. The first three doses are given at 2, 3 and 4 months as part of the 5-in-1 vaccine [6-in-1 vaccine as from September 2017], and the fourth dose is part of the pre-school booster at 3 years 4 months. This vaccine schedule has proved very effective in preventing pertussis in those who are vaccinated.

With high vaccination rates, there are fewer children with pertussis and there is less chance of transmission to very young babies who are not fully protected themselves by vaccination (i.e. babies under 3 months of age).

However, the vaccine used today does not offer lifelong protection from pertussis and those who are vaccinated as babies can catch the disease in later childhood or as adults. Even catching pertussis does not guarantee lifelong immunity – it can be caught again. Pertussis is a cyclical disease, with an increase in numbers of cases every 3-4 years. The reasons for this are not clear. Pertussis rates have risen in the last few years, especially among teenagers and adults, who could pass the disease on to young babies. In 2012, for example, there were nearly 10,000 cases of pertussis in the UK, and 14 babies died.

Before the pre-school booster was introduced in the UK in 2001, studies showed that nearly 40% of school age children who went to their GP with a persistent cough had evidence of recent pertussis infection. These studies helped to make the case for a pre-school booster that contained the pertussis vaccine.

Now a study led by Dr Kay Wang at Oxford University’s Nuffield Department of Primary Care Health Sciences has carried out a similar investigation to see what the current picture is. The study looked at 279 children aged five to 15 years who visited their family doctor with a persistent cough that had lasted between two and eight weeks. In total, 20% of these children had evidence of recent pertussis infection. 215 of the children in the group had been fully vaccinated, and 39 of these (18%) had evidence of recent pertussis infection.

A few of the children with confirmed pertussis infection had their coughs recorded, and some of these coughed more than 400 times in 24 hours. Pertussis is rarely fatal in this age group, but this does show how debilitating and unpleasant the disease can be for older children (watch a short film of a ten-year-old girl talking about her experience of catching pertussis). The vaccine seemed to work well initially but there were more cases of pertussis in children who had been given the pre-school booster over 7 years previously, suggesting a decline in protection over time.

The study suggests that the pre-school booster has made a significant impact in reducing levels of pertussis infection in school-age children. However, it shows that there are still significant levels of pertussis infection in this age group, and Dr Wang said that the findings ‘will help to inform consideration of the need for adolescent pertussis booster vaccination in the UK’. A booster could reduce cases of pertussis among teenagers, many of whom may think they have ‘just a bad cough’ when in fact they have pertussis. In turn, it could help to reduce transmission to babies too young to be vaccinated. More research will be needed to establish how effective a fifth dose of pertussis vaccine would be in cutting the number of disease cases.

Currently, however, the UK government is continuing to recommend vaccination against pertussis for all pregnant women as its key strategy for preventing pertussis in babies under 3 months of age. Antibodies from vaccinated mothers are transferred through the placenta to the baby, who then has the mother’s protection against pertussis from birth. The mother is also protected against catching pertussis and passing it to her newborn baby. This has been shown to be a very effective way of protecting newborn babies who are too young to be vaccinated themselves.

Read the abstract of the study

Watch a YouTube video of Dr Wang talking about the study

More information on pertussis and the pertussis vaccine in pregnancy

Watch a short film of a ten-year-old girl talking about her experience of catching pertussis

Page last updated: 
Thursday, January 4, 2018

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