Bacterial population struggles can affect the potential of vaccines

Scientists have shown how vaccinating against a common cause of pneumonia leads to lethal strains of bacteria being replaced by less harmful strains. The study provides a clearer picture of the complex population structures of bacteria and how different strains struggle to establish themselves. According to the researchers, the findings could help to optimise new vaccines by predicting how they will change bacterial populations in the longer term, based on how common certain genes are among the bugs. A better understanding of what makes some bacterial species so complex is critical to making better decisions about how to minimise the disease they cause Dr Nick Croucher School of Public Health Streptococcus pneumoniae , or the 'pneumococcus', are the most common bacterial cause of pneumonia, killing hundreds of thousands of children under the age of five each year. The microbes can also cause meningitis and blood poisoning in vulnerable patients. To combat the threat, a number of vaccines have been developed over the last decade. These interventions target the most deadly strains, enabling the body's defences to recognise these bugs and wipe them out before they can get a foot hold and leading to a drop in childhood deaths.