Sarah Boseley, health editor The Guardian, 21 April 2011
TB vaccinations in India. Scientists say some 20% of recent immigrants to the UK from the Indian subcontinent are tuberculosis carriers. Photograph: Anupam Nath/AP
TB screening misses 70% of latent casesUK should radically change tuberculosis screening policy and include arrivals from Indian subcontinent, experts say
The UK should radically change its tuberculosis screening policy and include arrivals from the Indian subcontinent, which could prevent most cases of the disease, according to scientists in a paper published today.
TB is a growing problem in the UK, where cases almost doubled between 1998 and 2009, and drug-resistant forms of the disease are spreading around the globe.
Arrivals from sub-Saharan Africa, which carries the heaviest TB burden in the world, are X-rayed – but the test only picks up active TB cases, of which there are very few. UK screening has been missing 70% of latent TB – where the person is a carrier of the disease and may become ill and infect others several years later.
Scientists writing in The Lancet Infectious Diseases journal say TB screening could be more effective by using a blood test to pick up latent disease.
Professor Ajit Lalvani from Imperial College London and his colleagues studied results from a highly specific blood test for latent TB at three immigrant screening centres in the UK between 2008 and 2009, and collected data on the countries people had travelled from.
They discovered that 20% of recent immigrants from the Indian subcontinent and almost 30% from sub-Saharan Africa are carriers of latent tuberculosis. They conclude that the current screening policy, which excludes immigrants from the Indian subcontinent – even though half of all active tuberculosis cases in the UK are in those populations – has been missing 70% of imported latent tuberculosis.
Changes to TB screening could pick up 92% of infected immigrants, they say, just by targeting younger people. They recommend that anyone aged 35 or under from a country with TB prevalence of 150 cases per 100,000 people should be given the blood test for latent infection.
That would include people from the Indian sub-continent. The change of policy, they say, would be cost-effective, because it would cost little more than what is spent at the moment, allowing for cases of active tuberculosis prevented.
"UK national guidance for which groups to screen has hitherto missed most immigrants with latent infection," said Lalvani. "By changing the threshold for screening, and including immigrants from the Indian subcontinent, we could pick up 92% of imported latent tuberculosis. By treating people at that early stage, we can prevent them from developing a serious illness and becoming infectious.
"Crucially, this wider screening could substantially reduce tuberculosis incidence while remaining cost-effective. Our findings provide the missing evidence-base for the new national strategy to expand immigrant screening."
The shadow health minister, Diane Abbott, called for immediate action on the findings. "It is alarming that we do not have comprehensive screening at ports of entry. I will be calling on the UK national screening committee to look at proposals for a cost-effective screening programme capable of identifying the vast majority of immigrants with latent tuberculosis," she said.
"Rates of tuberculosis continue to increase in many parts of the country. Much of this rise affects disadvantaged communities, including certain ethnic minority groups and those with social risk factors such as homelessness and drug and alcohol misuse.
"Healthcare in local areas must do more to ensure that people coming to live in the UK from high-risk countries are screened when they arrived at an airport or port, or when they registered with a GP. Students coming to Britain should also be tested."
http://www.guardian.co.uk/world/2011/apr/21/tb-screening-misses-most-uk-cases
TB vaccinations in India. Scientists say some 20% of recent immigrants to the UK from the Indian subcontinent are tuberculosis carriers. Photograph: Anupam Nath/APTB screening misses 70% of latent casesUK should radically change tuberculosis screening policy and include arrivals from Indian subcontinent, experts say
The UK should radically change its tuberculosis screening policy and include arrivals from the Indian subcontinent, which could prevent most cases of the disease, according to scientists in a paper published today.
TB is a growing problem in the UK, where cases almost doubled between 1998 and 2009, and drug-resistant forms of the disease are spreading around the globe.
Arrivals from sub-Saharan Africa, which carries the heaviest TB burden in the world, are X-rayed – but the test only picks up active TB cases, of which there are very few. UK screening has been missing 70% of latent TB – where the person is a carrier of the disease and may become ill and infect others several years later.
Scientists writing in The Lancet Infectious Diseases journal say TB screening could be more effective by using a blood test to pick up latent disease.
Professor Ajit Lalvani from Imperial College London and his colleagues studied results from a highly specific blood test for latent TB at three immigrant screening centres in the UK between 2008 and 2009, and collected data on the countries people had travelled from.
They discovered that 20% of recent immigrants from the Indian subcontinent and almost 30% from sub-Saharan Africa are carriers of latent tuberculosis. They conclude that the current screening policy, which excludes immigrants from the Indian subcontinent – even though half of all active tuberculosis cases in the UK are in those populations – has been missing 70% of imported latent tuberculosis.
Changes to TB screening could pick up 92% of infected immigrants, they say, just by targeting younger people. They recommend that anyone aged 35 or under from a country with TB prevalence of 150 cases per 100,000 people should be given the blood test for latent infection.
That would include people from the Indian sub-continent. The change of policy, they say, would be cost-effective, because it would cost little more than what is spent at the moment, allowing for cases of active tuberculosis prevented.
"UK national guidance for which groups to screen has hitherto missed most immigrants with latent infection," said Lalvani. "By changing the threshold for screening, and including immigrants from the Indian subcontinent, we could pick up 92% of imported latent tuberculosis. By treating people at that early stage, we can prevent them from developing a serious illness and becoming infectious.
"Crucially, this wider screening could substantially reduce tuberculosis incidence while remaining cost-effective. Our findings provide the missing evidence-base for the new national strategy to expand immigrant screening."
The shadow health minister, Diane Abbott, called for immediate action on the findings. "It is alarming that we do not have comprehensive screening at ports of entry. I will be calling on the UK national screening committee to look at proposals for a cost-effective screening programme capable of identifying the vast majority of immigrants with latent tuberculosis," she said.
"Rates of tuberculosis continue to increase in many parts of the country. Much of this rise affects disadvantaged communities, including certain ethnic minority groups and those with social risk factors such as homelessness and drug and alcohol misuse.
"Healthcare in local areas must do more to ensure that people coming to live in the UK from high-risk countries are screened when they arrived at an airport or port, or when they registered with a GP. Students coming to Britain should also be tested."
http://www.guardian.co.uk/world/2011/apr/21/tb-screening-misses-most-uk-cases
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