Since the middle of 2011 there has been an increase in reported cases of whooping cough in England and Wales. The current outbreak is the largest seen for over a decade with almost 5,000 cases confirmed so far this year.
What is Whooping Cough?
Whooping Cough (also known as Pertussis) is a bacterial infection causing an irritating cough that often develops into prolonged bouts of coughing. In children, the bouts of coughing are commonly followed by a characteristic `whoop' sound (except in infants) and may be accompanied by vomiting. In adolescents and adults, the symptoms may only be a prolonged cough. It is spread from person to person mainly by respiratory droplets in the air expelled during coughing or sneezing. The bacteria can also be spread indirectly, through contact with respiratory droplets on another person or object and then transfer to the mouth or nose. Anyone at any age can get it.
Neither immunisation nor natural infection gives life-long protection against whooping cough. Milder cases can occur in those who had routine vaccinations in childhood.
Why are pregnant women being offered the vaccine?
New babies have an immature immune system and they don’t mount the same immune response as they will when they are older. Maternal immunity passed onto a baby through the placenta and breast milk helps give them a few weeks protection whilst their immune system kick starts itself through contact with the world.
Before 3 months of age babies are particularly vulnerable to whooping cough. Some antibodies will cross the placenta giving the baby limited protection – particularly if the mother has had whooping cough. This passive immunity lasts for a few weeks.
This temporary programme of immunisation is being offered, on the advice of the Joint Committee on Vaccination and Immunisation (JCVI), to help produce/boost the antibodies in the mother. It is expected that these will then cross the placenta to boost the baby’s immunity and give protection after birth. It’s not known how effective this approach will be but it is felt by the JCVI that this is likely to be the most effective way of protecting newborn babies from infection or to reduce the severity of the symptoms and risk of complications.
It is considered that the optimal time to offer the vaccine is between 28 and 38 weeks of pregnancy, as it can take up to 2 weeks for the anti-bodies to be produced and passed on to the baby. Women who are 38+ weeks pregnant should still be offered the vaccine as some protection may still be provided.
More information from the Department of Health about the programme and the vaccination itself, including how it is being given, ingredients, patient information leaflet, side effects etc
Guidelines from the Health Protection Agency (HPA)
The advice from the JCVI (the Joint Committee on Vaccination and Immunisation)
Finally if you want more information on the progress of the outbreak take a look at the HPA infectious diseases pages.