MORE than 2000 people have caught whooping cough in Scotland's worst outbreak for at least 25 years.

The latest figures show 2005 people fell ill with the symptoms last year – among them 134 babies under one year of age.

In 2011, there was a total of 83 cases. The 2012 figures, which show the number of notifications submitted by GPs up to Friday, December 21, represent an increase of more than 2000%.

Dr Martin Donaghy, medical director of Health Protection Scotland, which has been monitoring the problem, said there are signs the outbreak has now peaked. He warned levels of the illness circulating in the community are still very high compared to previous years.

Pregnant women are being urged to accept the offer of vaccination against the germ in order to protect babies from whooping cough when they are born.

Mothers are also being encouraged to ensure their infants receive their routine vaccinations, which build immunity against whooping cough in three doses, on time.

Across the UK 13 babies have died in the current outbreak. So far there have been no fatalities in Scotland, but a number of infants have been so ill they were admitted to intensive care.

Dr Donaghy said: "Our number one priority now is to review the uptake of the vaccine within the key groups and see if it needs to be higher and see if we can increase uptake."

Whooping cough begins when a bacterium called Bordetella pertussis infects the lining of the airways and causes mucus to build. The mucus triggers intense bouts of coughing as the body tries to expel it. The airways also swell making them narrower than usual and resulting, among children, in the "whoop" sound as they gasp for breath after a bout of coughing. Their small respiratory systems mean they can develop complications including pneumonia and brain damage, which can be fatal.

Among the infants infected in Scotland, 64 were less than two months old and 113 were under four months. The vaccine is given at eight, 12 and 16 weeks.

Dr Donaghy said the rate of infection had been slightly higher in Scotland than England but it was now reducing, along with the spread south of the Border. He said: "In the last few weeks we have noticed it slowing down markedly. I think it may have come to a peak. These things are difficult to predict when you have not seen an outbreak for some time."

A surge in whooping cough is anticipated every three to four years, but both the scale and the speed of the 2012 bout has exceeded expectations.

The immunity provided by the vaccine can wear off in adolescence. One theory for the current out break is the number of people no longer immune to the virus and the number of people infected had reached a tipping point where the spread of the illness became likely.

A Scottish Government spokesman said: "We know whooping cough is highly contagious and it can be most serious for young babies under the age of one.

"Over recent months we have seen an increase in cases of whooping cough, which is why we introduced a vaccination programme for pregnant women to give newborn babies the protection they need. It's also important parents ensure their children are vaccinated through the Childhood Vaccination Programme, to help stop further spread of the virus."