Tuesday January 28, 2020

Vaccine Shows Promise for Preventing Latent Tuberculosis Infection from Turning into Active Disease

The lung disease kills more than a million people a year, mostly in poor countries, and about one-third of the world's people harbor

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Vaccine, Tuberculosis, Infection
A QuantiFERON-TB blood test. Data published in The Lancet Respiratory Medicine journal shows screening with QuantiFERON. VOA

An experimental vaccine proved 50% effective at preventing latent tuberculosis infection from turning into active disease in a three-year study of adults in Africa.

Doctors were encouraged because protection declined only a little after two years, and even a partially effective vaccine would be a big help against TB. The lung disease kills more than a million people a year, mostly in poor countries, and about one-third of the world’s people harbor the bacteria that cause it.

Results were reported Tuesday at a conference in India, the country hardest hit by TB, and published by the New England Journal of Medicine.

There is a TB vaccine now, but it’s given only to very young children and partly prevents severe complications. Researchers have been seeking a vaccine that also works in adults, to curb spread of the disease.

Vaccine, Tuberculosis, Infection
Doctors were encouraged because protection declined only a little after two years, and even a partially effective vaccine would be a big help against TB. Pixabay

GlaxoSmithKline’s experimental vaccine was tested in nearly 3,600 adults in Kenya, South Africa and Zambia who were infected with TB but who did not also have HIV, the virus that causes AIDS.

Half were given two doses of vaccine a month apart and the rest got dummy shots. Thirteen people in the vaccine group and 26 in the other group developed active TB.

The new results show that “the vaccine is holding up” over time, and mark an important step toward having a prevention tool that’s been sought for 100 years, said Dr. Paula Fujiwara, scientific director of the International Union Against Tuberculosis and Lung Disease, the group hosting the conference in Hyderabad, India.

Plans are underway for another, definitive study, which will take at least several more years, she said.

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After two-year results were announced last year, the World Health Organization called the vaccine a major breakthrough and has been holding meetings to discuss how to further its development. (VOA)

Next Story

Experimental Vaccine for Swine Fever Virus Shows Promise

When they deleted this gene, ASFV-G was completely attenuated

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Pigs, Swine Fever, Asia
Almost 5 million pigs in Asia have now died or been culled because of the spread of African swine fever over the past year, the United Nations Food and Agriculture Organisation said on Friday, warning Asian nations to keep strict control measures in place. Pixabay

Researchers have developed a vaccine against African swine fever that appears to be far more effective than previously developed vaccines.

Currently, there is no commercially available vaccine against African swine fever, which has been devastating the swine industry in Eastern Europe and Southeast Asia.

African swine fever virus (ASFV) is highly contagious and often lethal to domestic and wild pigs, according to the the study, published in the Journal of Virology.

“This new experimental ASFV vaccine shows promise, and offers complete protection against the current strain currently producing outbreaks throughout Eastern Europe and Asia,” said study researcher Douglas P Gladue from Plum Island Animal Disease Center, Agricultural Research Service, US Department of Agriculture.

The research was motivated by the 2007 outbreak of African swine fever in the Republic of Georgia.

“This was the first outbreak in recent history outside of Africa and Sardinia–where swine fever is endemic–and this particular strain has been highly lethal and highly contagious, spreading quickly to neighboring countries,” Gladue said.

“This is also a new strain of the virus, now known as ASFV-G (the G stands for Georgia),” Gladue added.

chinese pork, african swine fever
Pigs stand in a barn at a pig farm in Jiangjiaqiao village in northern China’s Hebei province on May 8, 2019. Pork lovers worldwide are wincing at prices that have jumped by up to 40 percent as China’s struggle to stamp out African swine fever in its vast pig herds sends shockwaves through global meat markets. RFA

For the findings, researchers set out to develop a vaccine. Part of the process of developing whole virus vaccines involves deleting virulence genes from the virus.

But when the researchers deleted genes similar to those that had been deleted in older ASFV strains to attenuate them, “it became clear that ASFV-G was much more virulent” than the other, historical isolates, because it retained a higher level of virulence, said Gladue.

The researchers then realised they needed a different genetic target in order to attenuate ASFV-G.

They used a predictive methodology called a computational pipeline to predict the roles of proteins on the virus. The computational pipeline predicted that a protein called I177l could interfere with the immune system of the pig.

Also Read: Indoor Dust Bacteria Have Transferrable Antibiotic Resistance Genes, Says Study

When they deleted this gene, ASFV-G was completely attenuated.

In the study, both low and high doses of the vaccine were 100 per cent effective against the virus when the pigs were challenged 28 days post-inoculation, the researchers said. (IANS)