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The East African : Sep 15th 2014
32 The EastAfrican OUTLOOK SEPTEMBER 13-19,2014 S CI E N C E the brunt of the TB burden, could have a dramatic impact on the global TB epidemic, preventing tens of millions of cases and millions of deaths from the disease. Preliminary results are expected at the end of 2015. If this initial study in adoles- cents shows that revaccination with BCG or vaccination with H4+ IC31 prevents infection with Mtb, then additional larger scale efficacy studies looking at the impact on TB disease in more diverse populations would be warranted. “Right now, we do not have a re- Residents of Mombasa on Kenya’s Coast mark World TB Day in 2010. Picture: FILE War on TB: New vaccine for adults in the pipeline Phase one studies have shown an acceptable safety and e∞cacy p≥ofile of H4 + IC31 By CHRISTABEL LIGAMI Special Correspondent A new tuberculosis vaccine for adults is in the pipeline fol- lowing the initiation of the first randomised, controlled trial — the most advanced stage of a study to determine the effectiveness of the vaccine on trial. The trial will examine the pre- vention of Mycobacterium tuberculosis (Mtb), the bacterium that causes TB infection through vaccination in adults. It will be conducted jointly by the global non-profit biotech Aeras and health care company GlaxoSmithKline (GSK). The study will enrol more than 3,500 healthy adults aged between 18-50, with latent (asymptomatic) TB infection. The adults will be picked from TB-endemic sub-Saha- ran African countries, starting in South Africa between this and next year, with a 36-month follow-up, yielding study results in 2018. The trial will also evaluate the bacille Calmette-Guérin (BCG) vaccine revaccination. That is, the vaccine will be given for the second time to establish its effectiveness. BCG is currently the only vaccine used to provide immunity against TB. It prevents some forms of TB in children, but its widespread use in infants has failed to control the global epidemic. Recent studies of BCG suggest that it may be effective at preventing infection, but this has not yet been tested in a randomised, controlled, prospective trial. The new TB vaccine, H4 + IC31 has already been tested in four Phase One studies — including one in South Africa — in adults, and showed an acceptable safety profile and immunogenicity (that is how safe and effective it is on the human body). As per the study, one-third of the participants will receive a BCG revaccination; one-third will receive vaccination with H4+ IC31, and one-third will receive a placebo. Infection will be determined with through the use of commercially available Interferon-Gamma Release Assays. These are wholeblood tests that can aid in diagnosing Mtb infection. Study models show that an effective vaccine given to adolescents and adults who bear “One out of 10 people who become infected with Mtb will develop active TB at some point in their life.” Prof Mark Hatherill, interim director of S. African Tuberculosis Vaccine Initiative liable way to prevent people who are exposed to Mtb from becoming infected; one out of 10 people who become infected will develop active TB at some point in their life,” said associate professor Mark Hatherill, the interim director of South African Tuberculosis Vaccine Initiative (SATVI). “Preventing new infections by vaccination, and interrupting the cycle of transmission would have a tremendous impact on the TB epidemic.” Clinical development of TB vac- cines is hampered by the lack of biologic correlates of protection and lack of validated preclinical models, which could provide evidence of the likely efficacy in early stages of development. While a TB vaccine would not need to prevent infection with Mtb to prevent TB disease, prevention of infection with Mtb would be an important marker of biologic impact. “For the first time in a TB vac- cine trial, we will be testing for infection by Mtb, rather than waiting to measure the occurrence of clinical disease, which is more expensive and requires much larger studies,” said Thomas Evans, Aeras President and CEO. “This will enable us to obtain results much more quickly and with fewer subjects, and the data we generate will ensure that the entire field of TB vaccine R&D progresses in a more informed and streamlined way.” Nearly nine million people be- come ill with TB each year. An effective vaccine to prevent TB would have a dramatic impact on the quality of life around the world, particularly in the regions where TB disease is most rampant — Asia and Africa. Mosquito-bo≥ne vi≥uses hit Japan and the US By DONALD G. MCNEIL JR New York Times News Service MOSQUITO-BORNE viruses are showing up unexpectedly in affluent countries where they have been largely unknown. Yoyogi Park, a popular oasis in downtown Tokyo, was closed last week after authorities realised it was the centre of Japan’s first outbreak of dengue in 70 years. Dengue is also called breakbone fever for the severe joint pain it causes. Repeat infections can cause dengue haemorrhagic fever, which can be lethal. Since Japanese authorities detected the first case August 27, 65 more have been found, most of them associated with Yoyogi Park. The victims included two models covering the outbreak for a local television station. Pedestrians cross a street in Tokyo on February 8. Yoyogi Park in downtown Tokyo was closed after discovery of Dengue carrying mosquitoes. Pic: AFP Fear of the virus is spreading. In Yokohama, officials closed a large beach park after one local woman infected in Tokyo said she was later bitten by a mosquito there. In the US, more than 750 cases of another painful disease, chikungunya, have been reported this year. Almost all have been in tourists returning from the Caribbean, where the disease is rampant, particularly in the Dominican Republic, Guadaloupe, Haiti, Martinique and Puerto Rico. Nine million Americans visit the Caribbean each year. But Florida residents who had not travelled were infected this summer, and the virus was found in a Texas mosquito, meaning that it is becoming established in the US. Chikungunya was unknown in the Western Hemisphere until late last year. Victims can often be seen walking stooped over with pain; the name means “bent up” in Makonde, an East African language. Most victims recover within a week, but in some, the pain persists for years. BRIEFS Study on Ebola vaccine gives hopeful outcome Scientists may have developed an effective vaccine for the Ebola virus after an experimental immunisation gave monkeys longterm protection from the deadly disease. Human trials for the experimental jab are underway at the National Institutes of Health (NIH’) in the US, raising the prospect that the vaccine can be used to help resolve the current Ebola crisis in West Africa. NIH’s studies show that a single dose of the vaccine can trigger fast protection, but the effect waned unless the animals got a booster shot. Want to eat healthy, train your brain The brain can be trained to prefer healthy foods over unhealthy highcalorie foods using a diet which does not leave people hungry, suggests a study. Scientists from Tufts University say food addictions can be changed in this way even if they are wellestablished. The scientists came up with the conclusions after scanning the addiction centre in the brains of a small group of men and women. A combination of vegetables. Pic: File To boost memory, excite your brain, says study Exciting a specific part of the brain with electromagnetic pulses could boost our ability to remember certain facts, a study in Science suggests. The US trials involving 16 volunteers found they made 30 per cent fewer mistakes in memory tests after the procedure. Scientists are now investigating whether the technique could help people with memory disorders and reduce memory loss in later life. How rising temperatures are affecting soils The huge stores of carbon locked in the world’s soils are more vulnerable to rising temperatures than previously thought. According to a research published in the Journal of Nature, researchers found that microbes in the soil were more likely to enhance the release of CO2 in a warming world. Soils from colder regions and those with greater amounts of carbon were seen to emit more as temperatures went up.
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