Chickenpox facts

Chickenpox is so-called to distinguish it from the stronger version of the pox - smallpox Chicken was used because of the term 'chickenhearted' to mean weak or timid The condition starts as red bumps which become blisters It is incubated for 14-17 days Complications can include pneumonia and the brain condition encephalitis

Eighty-one per cent of deaths from chickenpox between 1995 and 1997 occurred in adults.

There were 269 deaths from chickenpox between 1986 and 1997. That is up from 48%, 88 deaths from chickenpox in 1967-77 and 64%, 120, deaths between 1978-85.

There was a slight dip in the number of deaths to an average of 20 in all age groups each year from 1998 to 2000. Seventeen adults died in each of those years.

A chickenpox vaccine is available and is used in America, but experts say more work needs to be done to see if it would be beneficial to introduce it in the UK - and whether children or adults would need the jab.

Writing in the BMJ, the researchers said: "Mortality from chickenpox is not negligible."

Childhood protection

At the moment, most people catch chickenpox as children and therefore are protected from the disease later on in life.

Adults who have not had the disease, and heavily pregnant women should be particularly careful.

Mortality from chickenpox is not negligible

Professor Norman Noah, London School of Hygiene and Tropical Medicine

Researchers based in London obtained 119 copies of death certificates that mentioned chickenpox, or Varicella zoster, the virus which causes both chickenpox and shingles. from 1995 to 1997.

Using information from patients' doctors to clarify the diagnosis confirmed as definitely, or probably due to chickenpox in 75 (61%) of cases, around 25 per year.

In a further 19 cases, the disease present was shingles.

This compares to seven deaths from measles, mumps, whooping cough and Hib meningitis combined in 1996-97.

Men are twice as likely to die from chickenpox as women.

Those aged between 15 and 44 accounted for almost half of male deaths, and a quarter of all confirmed deaths from chickenpox.

Vaccine debate

Professor Norman Noah from the London School of Hygiene and Tropical Medicine said: "We need information, [about chickenpox], not only on the burden of the disease at primary and secondary care levels, but also on the effect of the vaccine on Herpes zoster (shingles).

"We also need to ensure a high enough uptake so that the disease does not shift towards the older population and a higher mortality."

Professor Noah told BBC News Online: "By any stretch of the imagination, if you say compare with road traffic accidents, 25 is a very small number. But it's there."

He and his team say there is insufficient evidence that a vaccine should be introduced because the natural immunity people develop after having chickenpox as children is effective in the majority of people, and how a vaccine would affect shingles would also need to be considered.

Dr Douglas Fleming, director of the Royal College of General Practitioners Birmingham Research Unit, said: "There may well be a case for vaccination. But more work needs to be done.

"And would we give it to children, or would the best age group be to say because children get chickenpox, then give the vaccination to adults," he asked.

A spokeswoman for the Public Health Laboratory Service said the paper contained "historic data", adding up-to-date data is now available that showed deaths had actually declined.

She said: "Any deaths from chickenpox must be taken seriously.

"However, compared to deaths from any other vaccine preventable disease there will be substantially less.

"Prior to the introduction of the vaccination programme for meningitis C, for example, there were around 150 deaths per year and people were often left with long-term complications."