New research has revealed that rates of disease caused by the bacterium “Streptococcus pneumonia” could be substantially reduced – by almost half – by changing our approach to vaccination.
S. pneumoniae is a bacteria often found at the back of the nasal cavity, where it is “normally harmless”. However, when it migrates to other parts of the body, it can cause serious bacterial infections such as pneumonia, sepsis and meningitis – known collectively as invasive pneumococcal disease (IPD).
In the study, researchers from the Wellcome Sanger Institute, Simon Fraser University in Canada and Imperial College London discovered that rates of infant IPD could actually be reduced by omitting components from the PCV13 vaccine to keep certain serotypes in place, removing the possibility of their replacement by highly-invasive serotypes.
The study, published in Nature Microbiology, simulated the performance of vaccines over time to assess the risk of vaccine-targeted strains being replaced by other potentially dangerous strains. Through this predictive modelling approach, the researchers identified new vaccine designs that could help reduce overall rates of disease.
The teams are now saying that the results highlight the need for vaccine programmes to be tailored to specific communities of bacteria and to consider vaccination at different ages.
S. pneumoniae is difficult to target with vaccines, because infection can be caused by different serotypes. Each part of a vaccine usually protects against a single serotype, with the most complex pneumococcal conjugate vaccine (PCV13) targeting 13 serotypes.
Because there are approximately 100 S. pneumoniae serotypes around the world, vaccine effectiveness varies between countries depending on which serotypes are present.
The approach to optimising vaccines will allegedly “help to address several problems, such as invasive disease among infants or adults and minimising antibiotic resistance in the post vaccine population” explained professor Caroline Colijn, of Simon Fraser University and the Wellcome Sanger Institute.
She continued to say, “Such an approach also enables public health policy-makers to assess the likely effectiveness of an existing vaccine for a local population based on genomic surveillance data.”
The findings coincide with growing alarm at the threat of antimicrobial resistance (AMR) to common medicines, as S. pneumoniae infections are sometime resistant to multiple antibiotics and have been highlighted as a priority threat by the World Health Organisation (WHO).
Last year a UN report revealed that if left unchecked, AMR could cause as many as 10 million deaths per year by 2050.
