Parents across the region are being urged to ensure that their children are vaccinated on time as a whooping cough outbreak continues throughout the UK, according to the Health Protection Agency.

Around 159 cases in the North West were confirmed by laboratory tests in six months to the end of June this year.

This compares to just 44 cases in the same period of 2008, the last year in which there was also a national outbreak.

The HPA says to get full immunity children should be vaccinated when they are aged two, three and four months old and given a pre-school booster at age three years and four months.

Doctor Sam Ghebrehewet, HPA North West’s regional immunisation lead, says it is vital jabs are given at the appropriate time.

“Babies and infants have limited immunity to infection and whooping cough can make them very ill indeed, so it is essential that children are immunised as soon as they reach the appropriate age for the vaccine.

"All too often we’ve seen vaccinations delayed, perhaps because of holiday commitments, and babies remain vulnerable in that period,” he said.

“My message to parents is that they should make the vaccination of their children, at the right time, a priority.

"Whooping cough is an unpleasant illness that can last for weeks and in extreme cases it can result in death. The best way to avoid suffering in the child and anguish in the rest of the family is to stick rigidly to the vaccination schedules.”

In England and Wales as a whole, 675 cases of whooping cough were reported to the Health Protection Agency in June, bringing the total for this year to date to 2,466.

This is more than double the total for 2011 when 1,118 cases were reported for the whole year. Increases were observed in all regions of the country.

Whooping cough - also known as pertussis - affects all ages, including very young babies who have the highest risk of severe complications and death.

To date in 2012 there have been five pertussis-related deaths in infants in England and Wales compared to four in the same period in 2008.

Symptoms of whooping cough include prolonged coughing in older children and adults and coughing fits accompanied by the characteristic “whoop” sound in young children.