24 March 2011

South Africa: Drug-Resistant TB - A Ticking Time Bomb

Countries with high numbers of people living with HIV, especially where access to antiretroviral treatment is patchy, are sitting on a drug-resistant tuberculosis (DR-TB) time bomb, which may have in some instances already exploded.

South Africa and other high burden countries are diagnosing the tip of the DR-TB iceberg with the large majority of people who have DR-TB (multi-drug and extensively-drug resistant TB) dying because they are not diagnosed or receive the medication when it is too late.

In the eighties and early nineties there was a belief that TB was under control and figures showed that the TB numbers were in decline. However, at the time those working in HIV were starting to ring the alarm bells, alerting international health authorities such as the World Health Organisation (WHO) that they were observing an increasing number of HIV patients presenting with and dying of TB, which was not responding to the first line drugs.

"We were pretty much told that we needn't worry and that DOTS (Directly Observed Treatment Short course) strategy, the WHO's intervention of choice for TB, would take care of the problem," recalls Medecins sans Frontieres' (MSF) Dr Eric Goemaere, who was trying to draw urgent attention to the problem in the late nineties.

More than 10 years later, Goemaere is overseeing projects where the HIV and TB co-infection rates are well over 70% and the number of drug-resistant TB patients rising steadily.

According to the latest global estimates, in 2009 there were 9.4-million people contracting active TB of which almost 2-millon have died. WHO figures reveal that the estimated number of MDR-TB cases is around 500 000 of which more than a quarter have died.

However, closer scrutiny reveals that less than 30 000 cases of MDR-TB have been reported worldwide, a paltry 7% of the estimated number, of which the majority were diagnosed in Europe and South Africa, as most other African countries don't have the diagnostic capacity. Even more worrying is that even less are receiving appropriate treatment, a mere 23 000 (5% of the total). Today as more TB resistance tests are performed, the concept of 'hot spots' is fading away while the world map fills-in with increasing number of diagnosed cases, rising mostly all over Southern Africa previous ' terra incognita'.

However, all is not doom and gloom. There are three steps that can be taken right now which will have a significant impact on the epidemic and save thousands of lives.

The first step involves diagnostics.

Dr Gilles van Cutsem, MSF's medical co-ordinator in South Africa and Lesotho has been working at the coalface of the DR-TB epidemic in Khayelitsha for a number of years. He pinpoints some outdated or complex diagnostics for DR-TB as one of the major challenges. The current method where sputum samples are collected and sent to a laboratory to be cultured is slow and complex with results taking anything from four to 12 weeks. While waiting these patients are not placed on treatment and remain highly infectious or die.

In South Africa drug susceptibility testing, which is the measure for DR TB is only done in patients with previous TB or for those who are failing on the first line treatment. This means that thousands of patients who acquired the DR TB strain in for instance a clinic, hospital, shop, at home or taxi would only be tested once they fail treatment and in many instances it may be too late by the time their test results are returned.

However, a new molecular (as opposed to culture) diagnostic tool, the first of which is called the Gene Xpert, is set to revolutionise the diagnosis of TB and DR TB. Although it has not been officially confirmed, the tool has impressed Health minister Dr Aaron Motsoaledi and set to be rolled out in South Africa.

The machine, which resembles a Nespresso machine, of which the smaller version is able to test four sputum samples at a time, delivers results within 90 minutes at the press of a button.

It has not been validated yet to diagnose extra-pulmonary TB fluids (TB that is not located in the lungs, a type of TB which affects many living with HIV), but it will diagnose the thousands of people who are living with a pulmonary TB strain that is resistant to Rifampicin, one of the mainstay first-line drugs. The tool will be a mixed blessing as it will confirm and bring to the fore the massive, but silent burden of DR TB. However, it will place pressure on surrounding countries that up to now have stuck their heads in the sand, claiming they had no money to treat DR-TB patients.

"Testing is essential as it will make the politicians realise there is a problem," said Goemaere. But large-scale effort will only happen if there is international support

South Africa's increasing commitment to finding DR-TB cases has seen the figures increase from 2 000 cases in 1999 to 6 000 in 2003 and 13 000 in 2008.

The second step needed to defuse the time bomb is to make the few drugs that are successful in treating DR-TB, more affordable.

At 2008 prices it is costing U$19 (R133) to treat and cure "normal" TB over six months.

If the patient is resistant to one of the drugs, the price of the MDR TB drugs skyrocket to between U$4 700 and U$5 500 (R35 000) for the two year course.

In the case of XDR TB the price rises to a staggering U$13 600 (R95 200).

According to an MSF report released this week the price of DR-TB drug Amikacin 500mg has increased by a staggering 864% between July 2001 and April 2011. Kanamycin has increased by 617% in the same period and Cycloserine and Capreomycin around 300%.

Patent is not an issue for all these 'old' drugs but quality approved manufactures are very few so increased demand raises prices while there is no working mechanism to control prices. Indications are that the South African public sector is paying way more than others who are also treating DR TB.

An example is PAS 4g sachets, which are being sold to the South African government at R80 per sachet (daily dose) while MSF international is procuring the same drug for $3.14 (R21).

Capreomycin is being sold to MSF at $4 (R28) per 1g vial, which is the daily-recommended dose, while government is buying it at more than twice the price (R69).

All of these drugs are old, have been around for many years and have a single producer. Many are arguing that with 14 000 confirmed cases South Africa becomes a substantial market and should be in a position to procure the drugs at significantly reduced prices.

The third and one of the most critical steps is to decentralise DR TB treatment to primary healthcare level, something MSF with the support of the Western Cape and Cape Town health departments has piloted with great success in Khayelitsha.

Basically it means that DR-TB patients, who have in the past been hospitalised for anything between six months and two years, are treated at their local clinic. HIV and TB services have also been integrated as a one-stop shop.

When it started in 2007 MSF sets as a goal improving the case detection of DR-TB, improving the treatment outcomes and decreasing DR-TB transmission.

The MSF model has added among others staff training and ongoing clinical support for all role-players, DR-TB recording, infection control, a local inpatient service and specialist outreach services such as paediatrics and audiometry screening (one of the horrible side-effects of the drugs is loss of hearing) to the existing TB programme.

Infection control has seen patients being triaged as soon as they arrive at the clinics - those with a cough are separated from those who are not coughing. In terms of environmental control waiting rooms are re-designed, windows are opened, sputum booths are established and where possible facilities are redesigned.

Wind driven turbines on the roof have also been hugely successful in ventilating the clinics.

Respirators for staff and paper masks for patients are also compulsory.

Community health workers conduct home visits to offer advice and ensure that infection control measures are in place.

The successes are already evident. Case detection has increased from 118 in 2006 to 231 in 2009.

More than 80% of patients diagnosed in 2009 and 2010 were started on treatment. The average time to treatment initiation decreased from 71 days in 2007 to 33 days in 2010. In 2010 72% of patients were able to start treatment at their local clinic, reducing the demand for hospital beds.

Among patients diagnosed with DR-TB in 2008, 62% were alive at 18 months after diagnosis. This is a massive improvement when taking into consideration that 72% of all DR-TB patients are HIV infected.

While much still needs to happen to tackle this epidemic, there are already enough tools to make a significant impact. Politicians and leaders need to step up to the plate.

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