A new study led by researchers from Harvard School of Public Health (HSPH) and the Wellcome Trust Sanger Institute in the UK has, for the first time, used genome sequencing technology to track the changes in a bacterial population following the introduction of a vaccine. The study follows how the population of pneumococcal bacteria changed following the introduction of the ‘Prevnar’ conjugate polysaccharide vaccine, which substantially reduced rates of pneumococcal disease across the U.S. The work demonstrates that the technology could be used in the future to monitor the effectiveness of vaccination or antibiotic use against different species of bacterial pathogens, and for characterizing new and emerging threats.

The study appears online May 5, 2013 in Nature Genetics.

“This gives an unprecedented insight into the bacteria living and transmitting among us,” said co-author William Hanage, associate professor of epidemiology at HSPH. “We can characterize these bugs to an almost unimaginable degree of detail, and in so doing understand better what helps them survive even in the presence of an effective vaccine.”

Pneumococcal disease is caused by a type of bacteria called Streptococcus pneumoniae, which is present in many people’s noses and throats and is spread by coughing, sneezing, or other contact with respiratory secretions. The circumstances that cause it to become pathogenic are not fully understood.

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