Marjory Stephenson Prize Lecture: Professor Martin Maiden

Posted on May 28, 2021   by Ellen Hinkley

The Marjory Stephenson Prize is awarded annually to an individual who has made exceptional contributions to the discipline of microbiology. The 2021 Marjory Stephenson Prize was awarded to Professor Martin Maiden. Professor Maiden gave the lecture titled ‘The application of population genomics to meningococcal disease’ at the Microbiology Society’s Annual Conference Online 2021. 
 

© Hertford College

Following an introduction to the Conference and to the Prize Lecture from the Society’s President, Professor Judith Armitage, Professor Maiden introduced his talk with with a tribute to the Prize’s namesake, Marjory Stephenson, describing how finding out about her life had been “an unexpected delight” when winning the prize. He highlighted the University of Oxford Biochemistry Department in which they both studied and worked at and went on to acknowledge the contributions the many people he had collaborated with had made to his career.

Professor Maiden has more than thirty years of experience in the NHS and academia, translating high-quality basic science into practical public health benefits, especially in the area of bacterial vaccines, vaccination, and food safety. In this lecture, he chose just one strand of this work, focusing on the population genomics of meningococcal disease. Professor Maiden introduced the audience to population genomics with PubMLST, a website which he set up with colleagues in 1998. The site was originally to host multi-locus sequence typing (MLST) data for population genomics, but now has been developed to be able to host multiple types of genomes, right up to whole genome sequences.

The rest of the lecture moved on to the real-world use of population genomics, with meningococcal disease the as the focus. Professor Maiden outlined the natural history of the disease, explaining how his team had used population genomics using European isolates, and found that the bacteria are mostly present as harmless commensals – meaning most of us carry multiple strains throughout our lives without realising – but can occasionally become a “accidental pathogen”, causing disease most often in infants and adolescents. Professor Maiden also discussed the characteristics of the genetic diversity between isolates, highlighting the relative stability of the antigenic region and that certain isolates were more likely to cause disease but less likely to be carried as a commensal. 

Moving on to vaccines, Professor Maiden provided an overview of two key outbreaks of meningococcal disease, and two subsequent key studies he had been involved in. Starting with the UK epidemic of the late 1990s, he spoke about introduction of conjugate vaccines, and the hope that they would provide long-lasting immunity and protect against carriage, to provide herd immunity, which previous vaccines had been less effective in doing. Professor Maiden and his team launched UK Meningococcal Carriage Study, sampling swabbed teenagers at the point of vaccination and then again two years later, and a similar study, carried out in an area known as the ‘meningitis belt’ in Africa. Professor Maiden gave an overview of the methods and findings of each study, highlighting the higher genetic diversity across the African isolates when compared to the European ones, and that both studies found that carriage and subsequently prevalence of the epidemic strains were greatly reduced by the vaccines, resulting in effective herd immunity that protected infants who experienced shorter-lived immunity following vaccination.

The final part of Professor Maiden’s lecture examined meningococcal disease and public health, this time focusing on the 2009 emergence in the UK of a particularly concerning meningococcal variant, which had been responsible for large epidemics in South America. He explained how analysis of isolates, following replacement of the booster of the previous vaccine with ACWY and Bexsero vaccines, showed a reduction in the versions of meningococci targeted by the vaccine, but also an unexpected reduction in one that wasn’t (serotype B). After further studies, it was concluded that rather than being vaccine-related, this was likely the result of a reduction in smoking and kissing in teenagers – the age group associated with high carriage - over the years of the study.

The lecture ended with some final thoughts, including on the effectiveness the social distancing on reducing meningococcal disease as well as COVID-19 transmission, the WHO’s target to defeat meningitis by 2030 and the work towards a new (serogroup B) vaccine. Professor Maiden finished by highlighting the message that, although the lecture had focused on meningococcal disease, the methods he’d referred to had wide ranging uses for many other organisms.

To learn more about Professor Martin Maiden’s research, read our recent Q&A.

You can view Professor Maiden’s full Prize lecture below.

Marjory Stephenson Prize Lecture 2021