Infant circumcision is seen as unnecessary genital mutilation by some. Flickr

Health experts are considering whooping cough booster jabs for teenagers and pregnant woman after five infants died in the worst outbreak for 20 years.

The Health Protection Agency said it was "very concerned" by the 2,466 confirmed cases of whooping cough between January and June, six times the 421 recorded in the last big outbreak in 2008.

Whooping cough, also known as pertussis, is a cyclical disease which spikes every three to four years.

Booster jabs may also be recommended for healthcare workers who treat young children.

Although whooping cough affects people of all ages, it is considered more serious for babies and infants. This year there have been 186 cases reported in infants under three months old, five of whom have died.

Dr Mary Ramsay, head of immunisation at the HPA, said: "The HPA is very concerned about the increase in cases and we are working closely with the Department of Health's Joint Committee of Vaccination and Immunisation (JCVI) to consider the most effective ways to tackle the outbreak.

"The JCVI is reviewing a number of options including the introduction of a booster dose in teenagers and offering whooping cough vaccination to pregnant women.

"We are reviewing our cases to see what interventions could have the quickest impact on the spread.

"Whooping cough can spread easily to close contacts such as household members. Vaccination is the most effective way to protect people and uptake in the UK is very good. In addition to this parents should ensure their children are up to date with their vaccinations so that they are protected at the earliest opportunity."

Babies are given whooping cough vaccines after two, three and four months and a booster jab three years later.