Doctor world

For the first time in 80 years, the vaccine tuberculosis (TB) has entered a new phase of clinical trials on its efficacy. Although the developers are optimistic about the result, the lung and TB experts warned that not too happy first.

TB vaccine, which was tested in Worcester, a distance of about one hour drive from Cape Town, developed by the South African Tuberculosis Vaccine Initiative (SATVI), supported by the Aeras Global TB Vaccine Foundation (AERAS), an organization dedicated to HIV research / TB.

News about the trials of new TB vaccine announced in the International Conference on AIDS Society (IAS) to-5 on Pathogenesis, Treatment and Prevention of HIV in Cape Town, July 2009.

Clinical trials, when the drug would be tested in humans, consists of three stages or phases. Phase-I aim to see whether the drug is safe use in humans, and involve small groups of 20-50 volunteers.

Phase-II, which aims to see whether the drug works well, involving hundreds of volunteers, and is often divided into two subtahap. While Phase-IIa assess how well the drug works, Phase-IIb centered on measures to be given to patients so that drugs worked well.





Test the third and final phase is the assessment of the potential of certain new drugs. Phase III involves a number of volunteers more, sometimes up to thousands of people, which is divided into two groups: one group received the drug, another group given a placebo. Requires up to 20 years before the new drug would get a green light.

Successful drug through Phase-II study did not necessarily continue. In 2007, tests on the Phase-III microbicide gel aimed at preventing HIV infection in women was stopped after scientists found that more participants were infected with the gel users than the placebo group.

Development of TB vaccines will start eight years ago, and will be tested on more than 2,700 children during the next few years. "If everything goes according to plan, the vaccine will be available in 2016," said Jerry Sadoff, President and CEO AERAS.

One of the concerns raised by the community during the conference, is whether people in developing countries - the most burdened by tuberculosis - able to buy the vaccine. "The price of new vaccines will not change, and will reach approximately U.S. $ 8-10 cents per dose," Sadoff said. "The price is comparable to the price of the vaccine Bacille Calmette-Guérin (BCG) today."

The reason behind the development of new TB vaccine for the current BCG vaccine is used, developed in the 1920s, proved to be ineffective to protect adults against TB bacteria. "BCG vaccine is to protect children against the development of severe active TB, but only until the age of 15 years. After that, people no longer protected, "said Harries. "The BCG is that we can not give a second dose after the first dose protection was gone."

In Africa, especially in adults and teenagers who develop TB, often due to HIV infection. People with HIV, because their immune systems are weakened, more vulnerable to TB. "It is estimated that people with HIV and are likely to develop TB 10% per year," Harries said. "People who are HIV-negative, and are likely to develop TB 10% for the rest of his life."

Based on the report Global TB Report 2009 by WHO, in 2007 there are 9.27 million new TB infections, and 1.7 million people worldwide - 456,000 of whom were also infected with HIV, died from TB.

In South Africa, one of the countries with the highest TB burden, from 461,000 cases recorded in 2007, 336,000 occurred among people with HIV. Among the 112,000 people who died from TB, 94,000 were HIV-positive.

Despite the magnitude of the problem of TB in Africa and other developing countries, scientists are just beginning to find a vaccine in about 8-9 years ago. "Once found, BCG proved effective in Europe, and the prevalence decreases rapidly," says Sadoff. "Therefore, people in Western countries think TB was defeated, so as not to create a new vaccine - even though in fact TB is vicious attack in the developing world, particularly among people with HIV," he added.

MDR-TB resistant to two of the best TB drugs, and XDR-TB resistant to most first-line drugs and second. In 90% cases of XDR-TB can be deadly. Both types of TB drug resistance may occur if non-compliant TB patients on first-line drugs, which must be used up to six months.