Cases of whooping cough in England and Wales have remained high through November, says the Health Protection Agency (HPA).
New figures released by the agency on Friday show 1,080 confirmed cases for November, down from October's 1,631, bringing the total so far for 2012 to 8,819, the highest for any year since the 1990s.
No deaths were reported for November, says the agency, who at the end of October said 13 infants had died in the current outbreak which began in the middle of 2011.
Although the slight fall in cases from October to November is the first downturn in the current outbreak, it does not necessarily mean it is coming to an end, as Gayatri Amirthalingam, HPA's consultant epidemiologist for immunisation, explains:
"The November figures show a welcome decrease of whooping cough cases since October. However, it is very important to note that we usually see a reduction in cases of whooping cough at this time of year so this decrease is in line with normal seasonal patterns."
Whooping CoughWhooping cough, also known as pertussis, is a highly contagious bacterial infection of the lungs and airways. The illness can last for three months.
The first signs of infection are usually a dry and irritating cough. This progresses to intense bouts of coughing followed by a "whooping" noise, which is how the illness got its name.
Other symptoms include raised temperature, runny nose, and vomiting after coughing.
Although whooping cough affects all ages, young babies are most at risk. Until they complete their vaccination around four months old, they are the ones most likely to have severe complications that can lead to death.
Older children and adults who get whooping cough usually get mild, unpleasant symptoms that rarely lead to complications.
Nevertheless, whooping cough is highly infectious. When infected people cough, they shed bacteria that can then be inhaled by others.
Vaccination for Pregnant WomenIn order to protect newborn babies, who do not start receiving the whooping cough vaccine until they are two months old, the Department of Health is offering pregnant women the whooping cough vaccination. They announced this at the end of September.
The vaccine being offered to pregnant women is called Repevax, which has been used to immunize children in the UK since 2004.
The aim of the campaign is to boost the short term immunity mothers pass on to their babies while they are still in the womb.
Although it is too early to see if this is having an effect on the current figures, the Department of Health recently reported a take up rate of around 40% in pregnant women.
While encouraged by the take up rate, Amirthalingam urges:
"We would like to remind pregnant women how serious this infection can be in young babies and how it can in some cases cause death. Vaccination between 28 and 38 weeks of pregnancy should offer babies the best protection against whooping cough before they receive their own vaccines."
It is also important, says Amirthalingam, that parents make sure children receive their vaccinations on time, even babies of women who were vaccinated in pregnancy, in order to ensure their continued protection through childhood.
And parents should also be alert to the signs and symptoms of whooping cough, "which include severe coughing fits accompanied by the characteristic 'whoop' sound in young children but as a prolonged cough in older children or adults", says Amirthalingam.
More information on the whooping cough vaccine for pregnant women is available on the NHS Choices website.
Affecting Whole CountryThe current outbreak is affecting the whole country, but the south west and south east have seen more cases than the north east and Wales, according to a report in the Telegraph.
The outbreak is not due to parents stopping their children being immunized, say experts. The illness tends to come in waves, as immunity provided by vaccination weakens over time, allowing small outbreaks to occur.
The United States is facing a similar surge in whooping cough cases, thought to be the highest in half a century.