[pronut-hiv] From NAM/Aidsmap:Early infant HIV diagnosis - Part 2

["ProNut-HIV" <pronut-hiv@healthnet.org>]

Scaling up early infant diagnosis
These reports served as models for other countries introducing early infant diagnosis into their own programmes. By the time of last yearâs HIV Implementersâ meeting in Kigali, Rwanda, teams from 9 countries reported on piloting DBS or gave updates on the challenges expanding from pilot studies to larger or national programmes. (See references at the end plus copies of some of the Power Point presentations can be found online here: http://www.hivimplementers.com/agenda/Apstracts-Agenda-Day3.html.) 

Together the programmes, represented by the panelists at the breakout session, had collected DBS samples from over 20,000 infants within the past year, up from only a couple of thousand or so reported at the meeting the previous year â leading to the diagnosis of about 2000 HIV-infected children. 

The presentations also demonstrated strengths and weakness in the countriesâ PMTCT programmes. For instance, Dr. Dominic Karanja of Pathfinder International in Kenya reported on a pilot DBS study that found an overall infection rate of 16.6% for the sites involved â âbut in some centres, the infection rate was zero, and in others it was high, around 30%! So we really need to go back and try to see what the reason is for this variation in infection rates,â he said.

These projects didnât always run smoothly; nevertheless, on the whole, presenters and participants in the session seemed enthusiastic about the prospects of dramatically improving early infant diagnosis in their countries within the next few years. 

Yet some significant challenges to full scale-up and performance remain, though the severity of the problem or the type of solution varies from country to country. 


Cost
While DBS collection may remove some of the logistical constraints to early infant diagnosis, the cost is still high. 

Most of the studies described below utilise the Roche Amplicor HIV DNA test, which is a qualitative test that does not give a viral load result but rather a yes or no answer to whether HIV DNA is present in the sample. This requires the use of different laboratory equipment that is not yet available in many countries, with the requirements for additional training of staff, different reagents, and backup service. 

âThe equipment for the HIV DNA PCR test is not interchangeable with the HIV RNA PCR test,â says Dr. Gayle Sherman. âFor a start, the extraction and the detection steps for the DNA test are still manual whilst for the RNA test these are automated.â 

Many programmes and policy makers are interested in whether they could rather perform viral load tests on DBS for infant diagnosis using existing equipment. Running viral load tests on DBS may have potential, but such tests may only diagnose children with detectable viral loads and thus may not be as reliable or sensitive as HIV DNA PCR in infants whose mothers are on ART or who have received complex PMTCT regimens. 

Nevertheless, there would be significant advantages to using the same technology which is already being rolled out in many settings, so further research is urgently needed to validate the clinical utility of performing viral load tests on DBS samples, especially from ART or PMTCT-exposed infants. 

Some newer PCR equipment, such as the Cobas Taqman, has the capacity to do both HIV RNA and DNA on liquid samples, but the extraction technique on DBS that Dr Sherman and colleagues perfected has not yet been adapted for use with this equipment. However, studies on DBS are underway and look promising for the future.

Alternative and newer technologies that may one day further reduce costs are discussed toward the end of the article. For now, âthe DNA test remains the gold standard test for early infant diagnosis,â says Dr Sherman. 

In addition to the equipment costs (which Dr Gozalez estimated to be around $50,000 in 2006), the total cost of performing each DBS test ranges roughly from $15-21 (including the cost of using the $8.00 Roche Amplicor HIV DNA PCR kit) depending on the lab. Tter if a second test is run to confirm a positive result â but since false positives are rare, some programmes forgo this step in favor of performing an antibody test once maternal antibodies should have cleared (more below). In Botswana, the policy is to simply run a viral load test in any infant who tests positive on HIV DNA as a way to both confirm the result and stage the infantâs disease and risk of progression.
 

Rapid HIV antibody testing
One way to possibly cut costs would be to first use a rapid HIV antibody test (RHT) (which costs about $1.20 per test, and is less sensitive to maternal antibodies) because some infants clear their motherâs antibodies faster than others. If the result comes back negative, there is no need to send out a DBS for PCR. 

Dr Jaco Homsy of the CDC in Uganda reported the results of a study using rapid HIV testing (RHT) prior to DNA-PCR for early HIV diagnosis in 394 asymptomatic HIV-exposed infants between the ages of 6 weeks and 18 months in Tororo District Hospital, Uganda. 

Of the 167 infants who were tested at the first immunization visit (6 weeks to 3 months), only 11 out of 167 rapid tests came back negative â and a couple of these who were still breastfeeding later became positive anyway. However, after 3 months of age, the negative predictive value (the ability for a negative test to be reliably negative) was 96%. The positive predictive value was low under 9 months of age, but after 9-12 months rose to 86% and above. This led Homsy and colleagues to devise the following testing algorithm.
 

Simplified testing algorithm
In HIV-exposed asymptomatic infants 18 months>

-  RHT for all infants starting at 6 weeks

o RHT NEG result at any age = child is HIV-negative (unless breastfeeding)

o RHT POS result:

â9 months: - care & refer as HIV+

9 months: send for PCR>Â                     PCR results are definitive at any age unless child is still breastfed (BF)

- If child is still breastfeeding, repeat RHT >6 wks after weaning

-  If not tested by PCR, confirm RHT result at 18 months

âThe cost saving that was incurred by using this algorithm instead of doing PCR on all infants gave us a US $2.40 saving per infant tested â which did not account for the turnaround [which was long for PCR results], the time wasted in terms of having the mothers come back, or the transport cost for the mothers,â said Dr Homsy. âSo rapid screening of all over 6 week old HIV-exposed asymptomatic infants is a time and cost-saving strategy that could substantially reduce the number of infants requiring PCR testing (up to 35% of the infants we tested in this population).â

Clearly, the savings from using RHTs would be greater when larger numbers of somewhat older infants are being tested. The median age of children being tested for many of the pilot projects discussed at the Implementerâs Meeting was generally much higher than 6-8 weeks and this will remain the case until countries are able to scale-up testing that identifies and tests most of the 6-8 week old HIV-exposed infants visiting immunisation clinics. 

But in a talk at the IAS meeting about a month later, Professor Susan Fiscus of the University of North Carolina raised a note of caution about the manner in which RHTs are being marketed in resource-limited settings. 

âThere are over 60 rapid antibody tests that are now available made by commercial companies who want to make some money. They go from country to country saying, âWell why donât you switch from the assay youâre doing now to this other. Itâs a new one, itâs better, itâs faster, itâs cheaper.ââ 

ââWeâre cheaper,â catches a lot of attention and Ministries of Health will frequently change from doing Rapid Test A in 2005, to Rapid Test B in 2006. And that means everyone has to be re-trained and there are other questions as well, such as âhave these new kits been properly validated for the population and the situation that itâs going to be used?â sother feature of many of the pilot studies is that they were testing infants known to be HIV-exposed. Most of these come from PMTCT programmes, and indeed, one reason for doing DBS is to monitor the effectiveness of PMTCT programmes as soon as possible at their first immunisation visit (and before they are lost to follow-up). 

But it goes without saying that uptake of HIV counselling and testing, and subsequent utilisation of PMTCT services varies dramatically from country to country or from site to site within a country. For instance, Botswana can boast that 94% of its HIV-positive pregnant women received either PMTCT or ART in 2006 (Jimbo). But in Tanzania, âover 50% of rural Tanzanian women deliver at home, hampering provision of HIV counselling and follow-up of HIV-positive and exposed infants and the national PMTCT coverage is also low, at 12%,â said Dr Yohanna Abraham of ICAP. 

And one key observation made by Dr. Rollinâs surveillance study was that a significant proportion of women with HIV in KZN, South Africa had not accessed PMTCT services at all. In addition, there was another group of women in that survey who reported being tested during pregnancy but who seemed to have seroconverted after that test and who were much more likely to transmit HIV to their infants (possibly because of the high viral loads common during acute infection). 

Notably, in a report at the IAS conference last year, use of a serological testing algorithm with a detuned assay for recent HIV seroconversion when applied to samples from the 2005 Sentinel Surveillance exercise in Botswana, detected a startlingly high rate (8% annual incidence) of new HIV infections among pregnant women (meaning, that these women most-likely became infected while they were pregnant) (Moyo). Women are at particularly high risk of infection during and just after pregnancy, and the routine testing offered by PMTCT programmes may not always detect a womenâs HIV infection status when she gives birth or is breastfeeding. Programmes must improve prevention counselling and support for those women who test negative.

But the other point is that not only do PMTCT programmes have to improve follow-up and get the HIV-exposed infants that they know about in to be tested, but that many HIV-exposed children arenât even on the PMTCT programmeâs radar screen. 

HIV counselling and testing services must be expanded at other entry points in the mother- child health platform: from antenatal services, labour and delivery, immunisation, postpartum care, family planning, and sick and well baby clinic services. 

Dr Abraham reported on a pilot programme to increase counselling and testing available in the MCH platform in two district facilities (based upon rapid antibody testing since they did not yet have access to PCR). Over the course of 9 months, the programme succeeded in increasing the numbers of women and children tested (though only 8% of the total visits were tested) and 335 HIV-exposed children were detected and 81% successfully referred into care. 

In another ICAP pilot project in Tanzania, DBS for DNA PCR was introduced into 4 sites â and most of the HIV-exposed infants were referred for testing by the PMTCT programme or were referred by an HIV Care and Treatment Clinic. 14% were identified from paediatric wards, MCH, home-based care and VCT sites (Nuwagaba-Biribonwoha). 

But in Abrahamâs study, the results in the sick baby clinic in the study were particularly telling. Over half the number of infants who were delivered eventually wound up in the sick baby clinic (4354). Only 4% of these received testing and counselling, and yet of all the MCH services, the sick baby clinic had the highest percentage of children who tested positive (24% vs 8.5% in the well baby clinic).

In another report, Dr. Sandra Owoses of the Namibian Ministry of Health and Social Services, stressed that clinical observations alone would lead to an overestimation of transmission among HIV-exposed children, strength symptoms were infected versus 13% of those without symptoms. 

So if programmes are rolling out in early infant diagnosis, and are looking for the kids that the PMTCT programme missed, the very first place to stop must surely be the sick baby clinic. 

âBut large numbers of mothers are still untested in the MCH and this is because the clinics are congested. There are no additional staff there to offer these services, and with the introduction of new services or a new approach, there are always challenges,â said Dr Abraham.


Remembering to start with the mother first
âWe have to test all mothers and infants,â said Dr Homsy. âBut our national policy and procedure is that no infant should be tested without getting her mother tested first. If the infant comes with a caregiver other than the mother, then it is tested independently of the motherâs results. But if the mother is negative, there is no point in testing the infant.â 

Acceptance of routine HIV testing and counselling among women making MCH visits has been exceptionally high in Tororo, Uganda. 

âIn terms of consent from the mother, yes, we have less than 2% of the mothers opting out. If it is not documented on the MCH card of the child that [the mother] has been tested and is positive, then we test them and they consent. There is very little opt-out in our setting after routine counselling and testing. Actually when they know they are positive they are extremely concerned to know the result of their child,â said Dr. Homsy.

Community sensitisation and engaging a community response
MCH services can be strengthened to integrate increased HIV counselling and testing by incorporating community-based responses. WHO has put together a resource on this: http://www.who.int/child-adolescent-health/publications/CHILD_HEALTH/Community_IMCI.htm. 

Community-based mechanisms are important in getting mothers and, if necessary, their infant tested so that both get linked to care, according to Dr Addy Kekitiinwa of Baylor College of Medicine Childrenâs Foundation-Mulago Hospital in Uganda, who described a project trying to better link PMTCT with MCH services.

âWe had peer HIV-positive mothers identify newly diagnosed HIV-positive women at antenatal clinics and then introduce HIV infected-pregnant women to the MCH clinic. The peer mothers were vital in implementing a successful PMTCT linkage.â

âIn Botswana, we also have a cadre of lay counsellors who go into the community to mobilise the mothers to bring the infants so that they can be tested in good time,â said Dr William Jimbo of BotUSA

âYou have to make a link with your community,â said Dr Gonzalez. âYou have to take your community based organisation and train them how to go to take a look â they know which mother is pregnant and where they delivered. And try to listen.â 

âWe have a programme officer and a nurse coordinator for the programme based within the Great Lakes region,â said Dr Harriet Nuwagaba-Biribonwoha of ICAP in Tanzania. âThey are now well known within the community and theyâve actually been to churches, to community meetings, to mosques and trying to tell people about these programmess and trying to involve them. And that involvement has included both mothers and fathers,â she said.


Unique infant identifiers
Once an HIV-exposed infant has been identified, another key challenge is keeping track of it and matching any testing samples to the patient. 

In Ethiopia, âduring the launch of the DBS programme, regional NGOs and partners working at different levels developed an infant unique identifier system for identification of exposed infants, testing them and linking them into treatment programmes,â said Dr Hailegiorgis who also works with ICAP.

Upon first identifying an HIV-exposed infant, each child is given a unique infant diagnosis identifier that is put onto the childâs health card (tracking him or her through the various programmes) and which is used to iderepeat samples). This number is used to track the samples, and the system can include additional information relevant to the child or the programme (much more detailed information on setting up such a system and logbooks is available through ICAPâs Manual on Infant Diagnosis (see http://www.columbia-icap.org/resources/peds/files/Infantdx050307.pdf). 


Training
To scale up implementation of DBS, more training will be needed. 

âWe need to have core trainers,â said Dr Mudany, âby doing training of trainers and picking out master trainers who can go around training within the regions.â

Dr Homsy pointed out that the training should engage the entire range of healthcare workers, from the laboratory personnel to the midwives.

âIn our case, itâs the midwives who do the rapid tests and DBS collections, and after the quality assurance that we carried out, we found that the midwives did systematically better than the lab techs!â

Much of the training across the PEPFAR focus countries starts over the border.

After ICAPâs experience with PCR in Rwanda, Dr Gonzalez said âwe bring in the technicians from other countries to Rwanda to be trained in one month/one month and a half with senior technicians and it is working very well,â he said.

A dedicated space for DBS collection
Since DBS is only being collected on HIV-exposed babies, there is a chance that it could lead to HIV disclosure, if it is not done in a private room.

âInitially, there was no dedicated space for exposed-infant diagnosis which caused a loss of confidentiality in some cases so these are now developed immediately,â said Dr. Hailegiorgis.

 

Getting the DBS samples to the centralised lab â establishing a routine, reliable and rapid transport service
A key feature of the DBS system is that the samples can be sent to the lab in an envelope, without refrigeration. However, there is little point in collecting the DBS specimens, sticking them in a drawer or shelf for weeks or even months and then sending them to the lab (a common problem if staff are not adequately trained or provided with a routine way to send samples to the lab). 

âWe need to put in place an effective transport system that links up the facilities with a laboratory,â said Dr. Mudany. 

This is more challenging in some settings than others and Dr Gonzalez suggested that each programme must work out the logistics for transport that works best in its setting (especially for more remote sites). 

âIn the case of Rwanda, we use the same car to move from Kibuye to the capital taking the medicines, the reagents for the CD4 â or whatever â once a week. You just put everything together in the same car, and we give the envelope with the DBS to the driver and the driver will drop the samples into the national laboratory and the same transportation brings the results back. Or you have a DHL system like in Botswana and thatâs a good way to do it there. But for Rwanda, our system works very wellâ and the cost of transportation is zero, because you use the transportation that already exists.â 

But he added that Rwanda is a small country with the capital (and the lab) right in the middle of it. And the transportation infrastructure in many countries is particularly poor, especially during the rainy season.

In a place like Ethiopia, itâs a different question altogether. The first phase of the DBS roll-out in that country utilised one centralised lab in Addis Ababa, and some samples were routinely transported from as far as 770 km away to the central lab â even though regional labs are now being brought online. âSpecimen transport is still a challenge because of the long distances,â said Dr Hailegiorgis. âFast, affordable, reliable and sustainable courier systems for specimen transport are required when PCR testing is centralised.â

Long turn-around times and the need for well-coordinated laboratory strengthening and quality control
Another challenge that many s cannot immediately meet the new demand and there were often backlogs at the lab. Dr Homsy reported a PCR turn-around time of 70 days during his study, though he said that was due to an initial backlog that should now be resolved. 

There is a danger that ability to collect and deliver DBS to reference laboratories could outstrip the capacity in the labs, if those are not strengthened, supply chains established, and/or new facilities brought online fast enough. 

For instance, in trying to scale-up implementation nationwide, Botswanaâs programme collected over 6,500 DBS between November 2006 and May 2007 â but had only tested and delivered results to the districts for 3,135 samples, due to delay in opening a second lab, and reagent supply interruptions. 

Mr Madisa Mine from the Botswana HIV Reference Lab also stressed that a successful pilot project does not necessarily lead to successful roll-out without training more technicians and without adequate resources being allocated to improving laboratory capacity.

And he pointed out that the laboratory must continue to do its regular work while taking on these new tasks, and that quality control and assurance must be ongoing. 

This again raises the issue of how limited laboratory capacity should be allocated in countries.

In South Africa, which is much better resourced than most countries, lab capacity has grown by leaps and bounds. Even so, the demand is so great, and access can still be difficult for rural clinics that often serve thousands of people with HIV. So one of the responses has been to bring PCR capabilities closer to the bigger remote clinics. 

âOne solution that we have tried is a laboratory in an adapted shipâs container,â said Dr Linda Gail Bekker of the Desmond Tutu HIV Centre at the IAS meeting. âIt has its own generator [particularly important in South Africa now that the power supply has become unreliable] and we estimate it would be able to serve 10,000 patients. We are testing it in a peri-urban situation and we do all the viral load and toxicity measurements and infant diagnosis testing there for a 4000 patient clinic in this container. And we have been able to show excellent quality assurance and quality control in this lab, compared with central laboratories.â

"Our greatest challenge is more rapid access to the results once the specimens have been taken. There is a considerable time delay ( partly because of distance and partly because of workload). Ideally we need a point of care test for children," said Dr Halima Darwood of Grey's Hospital in KwaZulu-Natal.

Delivery of results and follow-up
A couple of programmes reported that parents donât always come back for the test results even when the turn-around is relatively short. 

âWe have a challenge with mothers/parents who are not coming back for results,â said Dr Nuwagaba-Biribonwoha, âmaybe because the infants are negative, maybe because they are thinking the infants are not ill but they donât come back.â 

Again, community linkages and community-based follow-up are vital. Many South African sites are working with groups such as mothers2mothers, a peer-based programme that provides education and support for pregnant women and new mothers, which may provide the most efficient way to retain these mothers and infants in care (see http://www.m2m.org/).