HIV and other infections in Africa
The MRC has been carrying out pioneering research on infectious diseases in Africa for more than 90 years. Today, we continue to make significant headway in the fight against some of the world’s most challenging illnesses, including Hib disease, HIV and pneumococcal pneumonia.
Vaccine research in The Gambia: eradicating Hib disease
Sixty years of MRC research in The Gambia has led to a national vaccination programme that has completely wiped out Haemophilus influenzae type B (Hib) disease. One of the most common causes of meningitis and bacterial pneumonia in children, Hib is estimated to cause at least three million cases of serious illness and hundreds of thousands of deaths each year, mostly in developing countries.
MRC scientists first began work on Hib 20 years ago when they identified the bacterium responsible for the disease. Between 1993 and 1995, the MRC tested a vaccine against Hib in 42,000 Gambian children. The results persuaded the Gambian Government to begin one of the first country-wide Hib immunisation programmes in Africa. The researchers subsequently examined the vaccine’s effectiveness, looking at the incidence of Hib disease from the start of routine vaccination in May 1997 until April 2002. They found that Hib meningitis had been eradicated in children aged up to five1.
HIV treatment delivery
The MRC is continuing to fund research to improve HIV treatment delivery. The DART (Development of Antiretroviral Therapy in Africa) study is looking at the best way to deliver antiretroviral drugs in settings where resources are limited. Although antiretroviral therapy (ART) has dramatically reduced the number of people who die from HIV-related diseases in developed countries, the limited resources within health systems in many parts of Africa can make it difficult to use. In particular, the blood tests needed to check the effectiveness and side effects of treatment are expensive and require laboratory support, which is scarce in Africa.
DART is a multicentre trial taking place in Zimbabwe and Uganda in collaboration with the MRC Clinical Trials Unit and Imperial College London. It is being carried out at three sites: the MRC/Ugandan Virus Research Institute in Entebbe, the Joint Clinical Research Centre in Kampala, Uganda and the University of Harare in Zimbabwe. The 3,300 DART participants are randomly allocated to either a group that regularly sees a doctor with sophisticated lab support or a group seen by a doctor without such support. The volunteers will receive ART during and after the five-year trial, without which half of them would die within a year. Early results have revealed that after two years 94 per cent of participants are still alive – a staggering 17-fold reduction in deaths compared with mortality rates among HIV-positive Ugandans before ART was introduced.
While the main study continues, other findings from DART are also helping to provide answers for AIDS health policymakers in Africa and worldwide. For instance, the study has answered important questions about how to manage anaemia (low red blood cell counts) at the beginning of ART treatment, and has provided insights into side effects and effectiveness of different drug combinations. DART is a successful public-private partnership, with antiretroviral drugs donated by GlaxoSmithKline, Gilead and Boehringer Ingelheim and funding provided by the MRC, the UK Department for International Development and the US Rockefeller Foundation.
Pneumococcus vaccine: saving millions of children’s lives
Scientists at the London School of Hygiene and Tropical Medicine and the MRC Laboratories in The Gambia have found that vaccinating infants in the developing world against pneumococcus could drastically reduce rates of serious illness and death2. Pneumococcus bacteria are responsible for around one million deaths every year among children in developing countries. They invade the lungs and cause the most common type of bacterial pneumonia and can also infect the bloodstream or move into the fluids surrounding the brain and spinal cord, resulting in meningitis.
In the 1980s, MRC scientists worked to find an effective vaccine against pneumococcus in The Gambia. Between 2000 and 2003 they vaccinated nearly 9,000 Gambian children and compared them with children who received a dummy vaccine. Tracking the children for four years revealed that the vaccine was 77 per cent effective at preventing infection and resulted in a 16 per cent reduction in the number of deaths and a 37 per cent reduction in cases of pneumonia. The study was supported by international health research funders including the US National Institutes of Health, and the pharmaceutical industry.
A snapshot of some of the MRC’s ongoing work in Africa:
HIV
- Showing why type 1 HIV infection is more deadly than type 2 infection.
- Researching the use of a drug, nevirapine, to prevent mother-to-child HIV transmission.
- Observing 18,000 people in Kyamulibwa to see whether the HIV epidemic in Uganda is getting better or worse.
- Investigating whether the success of antiretroviral therapy has affected patient behaviour and how being HIV-positive is seen by the community.
- Testing the use of microbicide gel to prevent HIV transmission in 10,000 women.
- Examining differences in HIV progression, why some people who are exposed to the virus remain HIV-negative, and what happens to individuals infected with two subtypes of the virus.
Other research
- Research into the effectiveness of a new TB vaccine, MVA 85A.
- Monitoring 40 Gambian villages, including births, deaths and migration information, for a variety of population-based studies.
- Studying the effectiveness of hepatitis B vaccine in children, and its impact on rates of liver cancer in adulthood.
- Researching the effect of counteracting poor nutrition with dietary supplements on the reduction of stillbirths and early deaths of babies.
References
1. Adegbola et al. (2005). Elimination of Haemophilus influenzae type b (Hib) disease from The Gambia after the introduction of routine immunisation with a Hib conjugate vaccine: a prospective study. The Lancet, 366, 144.
2. Cutts et al. (2005). Efficacy of nine-valent pneumococcal conjugate vaccine against pneumonia and invasive pneumococcal disease in The Gambia: randomised, double-blind, placebo-controlled trial. The Lancet, 365, 1139.
MRC, July 2006