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[afro-nets] TB and Pneumonia vaccines
- From: "Claudio Schuftan" <email@example.com>
- Date: Sun, 23 Jan 2011 19:12:20 -0800
TB VACCINE PROTECTS BEFORE AND AFTER EXPOSURE
*A new vaccine that can fight tuberculosis (TB) before and after infection has been developed by Danish scientists.*
It could offer protection for many years more than is now possible.
TB is a huge global problem, particularly in developing countries, where access to antibiotics to treat the disease is limited.
The latest vaccine, so far tested in animals, is featured in the journal Nature Medicine.
TB is a disease of the lungs, causing symptoms such as coughing, chest pains and weight loss. Untreated, it can be deadly.
However, only in a small number of cases - fewer than 5% - do the symptoms develop immediately after infection.
In more than 90% of cases, once Mycobacterium tuberculosis, the bacterium which causes the disease, has invaded the body it changes its chemical signature, and lives in a dormant - or "latent" - state.
Usually the bacterium never emerges from this latent state, but in around 10% of cases it reactivates - often years or even decades later - to trigger severe symptoms.
Current vaccines, such as the BCG vaccine, work only if given before exposure to the bacterium.
They do not prevent infection, but do prevent acute symptoms and disease from emerging.
But once the bacterium has changed into its latent form it is effectively immune to the vaccine, and can bide its time, reactivating after the vaccine has ceased to have a preventative effect.
If successful in human trials, the new vaccine would be able to tackle that problem.
Developed by a team at the Statens Serum Institute in Copenhagen, it combines proteins that trigger an immune response to both the active and latent forms of Mycobacterium.
Researcher Professor Peter Lawætz Andersen said: "It might be possible to give a booster jab post-exposure to older children or even young adults which would protect them well into adulthood."
Although TB can be treated with antibiotics, those drugs are often not easily accessible in the developing world, where the new vaccine could have the greatest benefit.
Professor Andersen said: "In these areas you cannot go in and treat more than half the local population. For instance, in Capetown 60% of people are thought to be infected."
Professor Peter Davies, secretary of the group TB Alert, said: "A vaccine which can both protect against initial infection and protect from a breakdown of infection into disease is a major breakthrough.
"One of the main disadvantages of BCG was that it could only prevent infection going on to disease in the initially uninfected individual. It was therefore of no use in protecting infected adults who would become an infectious source of disease. Protecting children, though of value, does not protect against transmission, as children with active disease do not usually transmit disease.
"So far so good but we must remember that mice are not men (or women)."
Professor Francis Drobniewski, Director of the Health Protection Agency's National Mycobacterium Reference Laboratory said: "This is an exciting and thoughtful piece of research. The existing BCG vaccine is cheap, safe, widely used but of limited efficacy.
"With over nine million new TB cases globally each year and increasing levels of drug resistance new diagnostics, drugs and especially effective vaccines are desperately needed."
GAVI: PNEUMONIA VACCINE 'TO SAVE THOUSANDS OF LIVES'
*By Fergus Walsh *Medical correspondent, BBC News
The pneumonia vaccine is given as a series of three injections
*A new vaccine against pneumonia is being rolled out in Africa which, it is estimated, could eventually save more than half a million lives a year globally.*
Children in Kenya have begun receiving the jab, which will also be used this year in Sierra Leone, Yemen, Honduras and Guyana.
Infants in Nicaragua started receiving the vaccine a few weeks ago.
The Gavi Alliance - a global health partnership of public and private sectors for immunisation - says 19 countries are set to receive the jab, but many more could benefit if the funding becomes available.
Gavi says it needs an extra £500m ($800m) annually for the next five years to meet a shortfall in immunisation for existing and new vaccines.
The pneumonia vaccine protects against pneumococcal disease, the leading cause of severe pneumonia in children. It also guards against a form of meningitis and blood poisoning.
Pneumonia kills more children than any other illness, claiming around 1.7 million lives every year.
“The money needed for basic immunisation is in doubt, let alone for this effective new vaccine against pneumonia” Catherine FitzgibbonSave the Children
At the Langata health centre in Nairobi, scores of mothers brought their babies along for the first of three injections.
Beatrice Aching's son Wesley died from pneumonia in November. She brought her three-month-old daughter Tamara to be immunised. She said: "My son's death happened very suddenly. Wesley got sick in the morning and by evening he had died in hospital - I don't want that to happen to Tamara."
Leah Otieno's nine-month-old son Emmanuel got pneumonia before Christmas but recovered after antibiotic treatment - she says she is delighted to get him protected.
The charity Save the Children has launched a report, No Child Born to Die, which highlights the potential funding shortfall for global immunisation.
The report also says there is a critical shortage of 3.5 million health workers in poor countries, without whom millions of children will face illness and early death.
"Too many children are dying every day of vaccine-preventable illnesses and from the lack of basic healthcare," said Catherine Fitzgibbon from Save the Children. "The money needed for basic immunisation is in doubt, let alone for this effective new vaccine against pneumonia."
The pneumonia vaccine is given as a series of three injections
In June 2011, the UK government is hosting a meeting of Gavi in London which will be attended by world leaders. The UK provides a quarter of all Gavi's funding - more than any other nation.
Save the Children says it will be campaigning for rich nations to increase support for global immunisation, and for the pharmaceutical industry to lower the price of vaccines.
The pneumococcal vaccine costs £2.20 ($3.50) in Africa compared to £38 in Europe as a result of a deal between Gavi and two manufacturers: Pfizer and GSK. The roll-out in the developing world comes just a year after the same vaccine was introduced in the United States.
GSK said the discounted price is only fractionally above the cost of production. A spokesman said the vaccine takes a year to produce and is the most technically sophisticated of all its vaccines.
A second vaccine against rotavirus - the main cause of serious diarrhoea - is also being ready to be rolled out. But this, too, is far more expensive than the basic childhood vaccines against diseases like measles, whooping cough and polio.
Pneumonia and diarrhoea account for a third of all deaths in young children in the developing world. Gavi and Save the Children say a comprehensive roll-out of the pneumococcal and rotavirus vaccines could potentially prevent more than one million deaths annually.