Higher risk of TB in HIV+ kids ‘€“ study

KHOPOTSO: This is according to early observations of a study involving 1 300 infants, all of whom are born to HIV-infected mothers. The sample is divided into two groups. Eight hundred of the kids are HIV-negative, while 500 are positive. Leading the study is Professor Shabir Madhi, Co-Director of Wits University’€™s Respiratory and Meningeal Pathogens Research Unit (RMPRU).  

 

Prof. SHABIR MADHI: How to actually prevent HIV-infected children as well as children that are born to HIV-infected mothers, but that are not themselves HIV-infected’€¦ from developing tuberculosis. That’€™s the question that interests us.    

 

KHOPOTSO: The aim of the study is to investigate the possibility of preventing primary tuberculosis by way of using chemo-prophylaxis with one of two first-line medicines used in TB treatment.

 

Prof. SHABIR MADHI: When we mention chemo-prophylaxis we’€™re referring to using some sort of a drug. And the drug in the instance that we’€™re actually evaluating is called Isoniazid, abbreviated as INH.

 

KHOPOTSO: The study is being conducted at three sites, which include Chris Hani Baragwanath Hospital in Johannesburg, the University of Stellenbosch in the Western Cape and the University of KwaZulu-Natal.  

 

Prof. SHABIR MADHI: We’€™ve basically got two groups of children. We’€™ve got HIV-infected children and HIV-uninfected children that were born to infected mothers’€¦ Fifty percent of the children in each of these groups would receive Isoniazid (INH). The other 50% would receive a placebo. And we would basically provide them the drug from three months of age until two years of age. During that time period, if the child manifests any sort of symptoms of TB we would investigate the child. And obviously, we would only know at the end of the study whether this intervention of ours works or not.                                

 

KHOPOTSO: Prof. Madhi explains further.

 

Prof. SHABIR MADHI: We continue with the intervention, at least, until two years of age unless a child develops TB infection or TB disease in between’€¦ At two years of age we plan to stop the intervention drug and we would continue following up for another two years in each child just to see whether the effect of the intervention actually endures after the initial two years of prophylaxis. So, in total it would be a four-year period.

 

KHOPOTSO: The study started recruiting in November 2004. Preliminary results indicate that there is a huge burden of TB infection in children with HIV.    

 

Prof. SHABIR MADHI: When we started the study, our estimate was that over a two-year period about 12% of HIV-infected children would actually develop tuberculosis. Our preliminary data actually suggests that the incidence (the number of children that actually develop tuberculosis in one year in HIV-infected children) is around 20%. So, we’€™ve completely under-estimated the burden of tuberculosis that actually exists in HIV-infected children.

 

KHOPOTSO: I asked Prof. Madhi how the result compares with the incidence of TB in HIV-exposed uninfected children?

 

Prof. SHABIR MADHI: The incidence of tuberculosis in that group is probably about half of what it is in HIV-infected children ‘€“ closer on to round about 10%, which is still substantial.                                                    

 

KHOPOTSO: While the risk of getting ill from TB after the initial infection is quite significant in both groups, researchers note that it’€™s exponentially higher in kids diagnosed with HIV.  

 

Prof. SHABIR MADHI: In uninfected kids under two years of age, we know that it’€™s about 40% in the next year of life after being infected with TB. In HIV-infected children, we probably estimate that to be round about 60 ‘€“ 80%.    

 

KHOPOTSO: Until now, the strategy to prevent the development of TB, including pulmonary or lung TB in children, has been to vaccinate them early after birth with the BCG vaccine.          

 

Prof. SHABIR MADHI: The problem that we face with the BCG vaccine is that we know, firstly, that it’€™s not very effective in preventing pulmonary TB in children. It’€™s more useful in preventing extra-pulmonary TB, that’€™s TB meningitis and TB of other areas of the body’€¦ The next problem – and the more important problem that we face with the BCG vaccine now in HIV-infected children – is that there’€™s emerging data which actually shows that a BCG vaccine might actually be harmful to HIV-infected children.

 

KHOPOTSO: But even so, kids in Prof Madhi’€™s study still receive the vaccine as part of the routine immunisation programme for children. The professor says there is good reason to suspect that the intervention using chemo-prophylaxis with Isoniazid will prove effective.

 

Prof. SHABIR MADHI: There’€™s a study that’€™s been completed in South Africa’€¦ HIV-infected adults with a CD 4 count greater than 200 that have previous evidence of infection by TB. When these adults are actually prophylaxed with INH, we find that, actually, they have a reduced risk of developing TB subsequently. So, at least, there’€™s adult data to support the notion that this is the sort of strategy that might work in children. Our study is slightly different in that children that we’€™re looking at haven’€™t had previous infection by TB’€¦ We’€™re more interested in actually preventing the primary infection from taking place as well as the subsequent disease from developing.

 

 

Author

  • healthe

    Health-e News is South Africa's dedicated health news service and home to OurHealth citizen journalism. Follow us on Twitter @HealtheNews

Free to Share

Creative Commons License

Republish our articles for free, online or in print, under a Creative Commons license.


Leave a Reply

Your email address will not be published. Required fields are marked *

Stay in the loop

We love that you love visiting our site. Our content is free, but to continue reading, please register.

Newsletter Subscription