fresh tb vaccine developed

Implications for CST?


Fresh TB vaccine developed
By Sharon Labi
05nov04

AUSTRALIAN scientists have developed a new vaccine for tuberculosis they believe will stem the spread of the disease which kills three million people a year.

Researchers at Sydney's Royal Prince Alfred Hospital's Centenary Institute say the present vaccine, called BCG, lasts only 10 years and is 50 per cent effective.
They hope the new vaccine they have developed – which uses only part of the tuberculosis germ rather than the whole germ – will last 20 years, and tests on mice have so far shown it to be more effective than BCG.

Immunologist Professor Warwick Britton and his team have now sent the vaccine to laboratories in the United States for testing on guinea pigs with the aim of setting up human trials within five years.

Tuberculosis is a chronic disease involving destruction of tissue that damages the lungs and affects other organs including the brain.

Prof Britton said with three million people dying each year from the disease, it was vital a more effective vaccine was found and given to all newborn children in countries with high rates of TB.

Although BCG was of value in reducing the rate of tuberculosis in children, it did not contribute to the control of the disease because it only lasted 10 years.

Carriers of the germ also could develop TB later in life, he said.

"We're very fortunate in Australia that our tuberculosis rate is one of the lowest in developing countries but nevertheless there are still 1,200 people or so a year that develop TB," Prof Britton said.

"But we are surrounded by countries which have very high rates of tuberculosis so this is an example much like many other modern infections that Australia can't shield itself and pretend that we're not going to be infected by the major infectious diseases from the countries around us."

Indigenous Australians were eight times more likely to contract the disease than non-indigenous Australians, and people born overseas were 20 times more likely.

There also was the risk that TB could be reactivated in older Australians in cases where their immune system was weakened or due to medications such as for rheumatoid arthritis.

Overseas, one of the major contributors to the increase in TB is the spread of HIV, particularly in Africa.

One-third of HIV deaths were a result of active TB.

It is predicted that in the 20 years to 2020, one billion people will be infected with TB, and 35 million people will die as a result of 200 million active cases.