Does Nigeria have the highest incidence of tuberculosis in Africa, as its junior health minister has claimed? New World Health Organisation estimates show it's South Africa with the continent's biggest TB problem.
Nigeria’s fight against tuberculosis (TB) suffered a setback when a laboratory that analysed TB samples burned down in March 2018 .
During the visit he was reported to have said : “Nigeria also ranks fourth among the 30 highest TB burden countries in the world and first in Africa.”
This was according to the World Health Organisation’s 2017 global tuberculosis report , he said.
The minister’s aide, Itohan Ehanire, confirmed to Africa Check that the minister made the claim. However, she said he had mistakenly quoted the WHO’s 2016 tuberculosis report .
What is a ‘high burden’ TB country?
In the 2016 report, Nigeria was listed as one of 30 “high burden” TB countries. The WHO compiles its list from the number of new and relapse cases in a country in one year. This is known as the “incidence” of TB.
In countries with strong health systems, the number of cases reported to authorities are used to count incidence. In those with weaker systems, the WHO tries to work out how many cases of TB are not reported .
As the minister said, Nigeria’s estimated 586,000 new TB cases in 2015 were the world’s fourth highest and the highest in Africa – far more than South Africa’s 454,000 cases.
'Small changes not to be over-interpreted'
The WHO’s 2017 report uses 2016 statistics, the latest global tuberculosis data available. In the report, Nigeria drops to seventh place for the estimated number of new and relapse TB cases, at 407,000 . It now ranks lower than South Africa’s 438,000 cases.
But Dr Philippe Glaziou, a senior epidemiologist at the WHO’s Global TB Programme , explained that the drop in Nigeria’s incidence – of 32% – was due to “a re-estimation using new information and data”. Specifically, there were fewer HIV-positive TB sufferers than thought before.
Glaziou further warned that “small changes in ranking should not be over-interpreted, particularly when uncertainty ranges in the underlying estimates-overlap between countries”.
This is the case with the WHO’s upper and lower certainty limits for Nigeria and South Africa. The estimates for both countries fall within the same range , with Nigeria’s new cases in 2016 estimated at between 266,000 and 579,000, and South Africa’s between 304,000 and 595,000 cases.
Why the uncertainty?
It’s difficult to estimate Nigeria’s tuberculosis burden because there isn’t enough good data, Glaziou said.
In Nigeria, most new cases are not reported , Dr Victor Babawale, a senior officer with the National Tuberculosis and Leprosy Control Programme , told Africa Check.
“Our case notification, that is the number of cases we were able to detect in 2016, was 100,433. This is 24% of the estimated number of cases,” Babawale said.
Nigeria’s case notification rate is the lowest in the 20 countries on the high TB burden list. For example, Ethiopia’s rate was 69% and South Africa’s 54%, with Kenya and Mozambique both at 45%.
The national coordinator of Nigeria’s tuberculosis programme, Dr Adebola Lawanson, said “this picture needs to change”. One government intervention is to almost double the number of tuberculosis observation and treatment centres from 3,931 to 6,753 in 2010.
Nigeria has also been installing more GeneXpert machines – which offer a “while you wait” TB test – with 390 in place at the end of 2017 from just 32 five years ago. A newly developed electronic information management system is expected to help keep track of cases, especially in rural areas and on the outskirts of cities. More than this, some states are now treating TB patients for free .
Conclusion: Nigeria ranked 7th for new TB cases worldwide, 2nd in Africa
Nigeria’s junior health minister had reportedly claimed the country ranks fourth among the world’s 30 high tuberculosis burden countries and first in Africa.
His aide explained that the minister had mistakenly quoted the WHO’s 2016 tuberculosis report. The latest data shows that Nigeria had dropped to seventh place for the estimated number of new and relapse TB cases, down from 586,000 the year before.
However, much of the drop is due to revised estimates, especially of the HIV infection rate in Nigeria. Nearly three-quarters of TB cases are thought to go unreported – the highest such rate in the world.