'High risk' people should be immunised

Immunisation against hepatitis B was associated with a three-fold increase in the incidence of MS Lead researcher Dr Miguel Hernàn

People who are vaccinated against hepatitis B are at increased risk of multiple sclerosis, a study shows.

US public health experts found the link when they looked at data on more than 1,500 UK patients.

The Harvard team does not know whether the vaccine causes MS in those prone to the disease or speeds up MS in those destined to have it.

The benefits of protecting against hepatitis might outweigh any risk, wrote the authors in Neurology.

In the UK, people who are at increased risk of hepatitis B because of their lifestyle, occupation or other factors such as close contact with a case or carrier are advised to be immunised against this virus.

It is passed from person to person through blood contact. The virus may also be present in saliva, vaginal secretions, and other body fluids.

This means people at high risk include intravenous drug misusers, individuals who change sexual partners frequently, health care workers, prisoners and prison staff and those travelling to areas of high prevalence such as the Far East.

Conflicting evidence

About one in four infected of those with hepatitis B will develop a serious liver disease such as chronic hepatitis, cirrhosis or liver cancer develops after a number of years.

In recent years, concerns have been raised that the vaccine may trigger serious autoimmune diseases, especially multiple sclerosis

These fears were fueled in the 1990s when about 200 people in France developed MS shortly after receiving the hepatitis B vaccine.

In February 2001, the results of a long-term study of hepatitis B vaccine and MS in nurses were published in the New England Journal of Medicine.

This study, by researchers at Harvard School of Public Health, found no link between the two.

The association may be much less than the three fold increase suggested here   A spokeswoman from the British Liver Trust

However, some of the same researchers now believe there is a link.

In the latest study Dr Miguel Hernàn and colleagues looked at people registered with a GP in the UK who had been diagnosed with MS between 1993 and 2000.

When they looked at hepatitis B immunisation patterns among these 163 MS patients and 1,604 'control' patients without MS from the same GP database, they found a link between the vaccine and MS.

Dr Hernàn said: "We estimated that immunisation against hepatitis B was associated with a three-fold increase in the incidence of MS within three years following vaccination."

He said more research would be needed to find out why this might be.

Caution

"It is also important to stress that 93% of the MS cases in our study had not been vaccinated," he said.

Thus, for some, the small risk of MS posed by immunisation would be far outweighed by the protection against potentially fatal liver problems, he said.

In an accompanying editorial, Dr Robert Naismith and Dr Anne Cross from Washington University said: "This article should be viewed as another piece of the puzzle of MS causation."

It is obvious that the serious risks of hepatitis B vastly outweigh any very small possible risk from vaccination   A spokesman for the Multiple Sclerosis Society

They said the findings were not strong enough to suggest that current immunisation policy should be changed in any way.

A spokeswoman from the British Liver Trust said the findings were interesting but the suggested link should be viewed with some caution.

"Given that many vaccinations for hepatitis B are given in a workplace setting, it is possible that a proportion of vaccinations do not figure in the control group's records.

"We don't know whether that has been taken account of in the research.

"If it hasn't then the association may be much less than the three fold increase suggested here," she said.

A spokesman for the Multiple Sclerosis Society said: "We need to study these findings in the context of other recent research which has shown no link between the vaccination and MS.

"Even on this evidence, however, it is obvious that the serious risks of hepatitis B vastly outweigh any very small possible risk from vaccination."

The MS Trust agreed, saying: "On the basis of this study, one wouldn't want policy as regards to vaccine, to be changed, particularly with such a lethal disease."