July 27, 2012

expert reaction to HPA’s announcement that the whooping cough outbreak continues

The Health Protection Authority announced that cases of whooping cough, a childhood disease that has been all but eradicated, were still increasing rapidly in the UK.

Prof Adam Finn, Professor of Professor of Paediatrics, University of Bristol said: Why is this rise happening? “Partly because doctors are thinking of the diagnosis more and testing for it, but that is not the whole story. It’s also because the current vaccination programme has reduced whooping cough in children but also pushed it back into older age groups. Immunity due to vaccine does not last as long as immunity due to infection so as the number of people who have had whooping cough in the past falls, population immunity falls and rates go up. This is happening everywhere, not just in the UK.” Is it likely to continue? “Yes the trend, at least for the moment, is up.” Why is it cyclical? “Whooping cough always runs in 3 yearly cycles. This is about population immunity too. The number of susceptible people builds up, the epidemic occurs and dies down as the number of susceptible people falls. Then you go round again. The difference is that most cases are in young adults now not children. The problem is that sometimes young babies (too young to have been immunised) get it and get very sick or die.” What proportion of people needs to be immunised to reach herd immunity? “This is not precisely known. Coverage of the present childhood programme is very high in most places. So the problem is not really low coverage. Timing is significant and people who don’t have their children immunised on time would be well advised to do so given the increasing risks of disease.” Is the problem that people aren’t being vaccinated – and if so then why not? “Not really, no. See above. We immunise babies and pre-school children and most of them get the vaccine on time. The problem seems to be that the present vaccines, used the way we currently use them do not completely control the problem.” Should adults be getting boosters? “Possibly. However, it is difficult to reach adults with vaccines – there is no system in place for doing it, adults don’t think about it and they only go to the doctor when sick. Possible good ideas include boosters for pregnant mothers, parents/carers of new born babies and healthcare workers (particularly those who care for children and especially those who look after new-born babies).”