Prof Sir Brian Greenwood, London School of Hygiene and Tropical Medicine
Brian Greenwood qualified in medicine at the University of Cambridge, UK in 1962. Following house-officer appointments in London, he spent 3 years in Western Nigeria as a medical registrar and research fellow at University College Hospital, Ibadan. After receiving training in clinical immunology in the UK, he returned to Nigeria in 1970, this time to help in establishing a new medical school at Ahmadu Bello University, Zaria where he developed his research interests in malaria and meningococcal disease whilst continuing to teach and practice clinical medicine.
In 1980, he moved to the UK Medical Research Council Laboratories in The Gambia which he directed for the next 15 years. In The Gambia, he helped to establish a multi-disciplinary research programme which focused on some of the most important infectious diseases prevalent in The Gambia and neighbouring countries such as malaria, pneumonia, measles, meningitis, hepatitis and HIV. Work undertaken during this period included demonstration of the efficacy of insecticide treated bednets in preventing death from malaria in African children and demonstration of the impact of Haemophilus influenzae type b and pneumococcal conjugate vaccines when deployed in sub-Saharan Africa.
In 1996, he was appointed to the staff of the London School of Hygiene and Tropical Medicine where he is now Manson Professor of Clinical Tropical Medicine. From 2001-2009 he directed the Gates Malaria Partnership which supported a programme of research and capacity development in many countries in Africa directed at improving treatment and prevention of malaria. In 2008, he became director of a new capacity development initiative supported by the Wellcome Trust, the Bill & Melinda Gates Foundation, and the Malaria Capacity Development Consortium (MCDC), which operates a post-graduate malaria training programme in five countries in sub-Saharan Africa. He also directs the African Meningococcal Carriage Consortium which, with support from the Wellcome Trust and the Bill & Melinda Gates Foundation, has investigated the pattern of meningococcal carriage in seven countries in the African meningitis belt and demonstrated the impact of the serogorup A meningococcal conjugate vaccine (MenAfriVac®) on meningococcal meningitis and carriage in Chad.
The African Meningococcal Carriage Consortium (MenAfriCar) was established in 2007 as a partnership between seven African research centres and twelve partners from five northern countries to study carriage of Neisseria meningitidis
in countries of the African meningitis belt prior to and after introduction of the serogroup A meningococcal conjugate vaccine PSa-TT (MenAfriVac®) which was then being developed. The reasons why this initiative was undertaken, some of the challenges that it met and the consortium’s main findings will be presented.
During the course of over 20 cross-sectional surveys undertaken in age-stratified populations in seven African meningitis belt countries, nearly 50,000 pharyngeal swabs were collected. The overall prevalence of carriage of N. meningitidis across all surveys was lower than expected at 4%. The prevalence of carriage and the predominant serogroup varied markedly between countries and over time, as did the prevalence and species distribution of non-meningococcal Neisseria
Transmission of N. meningitidi
s was studied in 133 households in whom a carrier was identified during the course of one of the cross-sectional surveys. Serogroup W was the most prevalent serogroup identified in these studies and showed a substantial level of transmission within households, but evidence for transmission of N. meningitidis
outside households was found also. The average duration of carriage, around 3 months, was less than that usually found in industrialised countries. Measurement of meningococcal serogroup A specific IgG and bactericidal antibodies in six and two countries respectively showed high pre-vaccination antibody titres, as has been noted previously in the African meningitis belt. Seroprevalence by age was used in a catalytic model to determine the force of infection in six countries. Collection of blood samples at the start of the household studies will allow correlates of protection against carriage of some meningococcal serogroups to be investigated.
Methods of facilitating carriage studies were investigated in The Gambia where it was found that culture of swabs in broth overnight followed by identification of meningococcal DNA by PCR doubled the isolation rate. Adoption of this method could help to reduce the size of the populations needed to demonstrate differences in carriage prevalence in vaccine impact studies, and to improve the validity of longitudinal studies on the dynamics of transmission.
An important objective of the consortium was to demonstrate the impact of MenAfriVac® on carriage and it was planned initially to undertake these studies in Mali and Niger but no serogroup A meningoccci were found in the pre-vaccination surveys in these countries. However, carriage of serogroup A N. meningitidis
was found in Chad and, in this country, it was shown that MenAfriVac® not only reduced substantially carriage of serogroup A N. meningitidis
but that it also halted an epidemic caused by this bacterium.
The MenAfriCar consortium has received funding from the Bill & Melinda Gates Foundation and the Wellcome Trust. Return to main index