Disguised bacteria able to evade vaccines
Scientists have found that some bacteria have become able to evade efforts to vaccinate against them by developing a new disguise.
Their research is the result of a recent study into pneumococcus bacteria, which is responsible for infections such as pneumonia and meningitis. The researchers monitored how the pneumococcus bateria responded to the introduction of a vaccine, with the study showing that some bacteria managed to change their outer coat – known as capsule switching – to avoid succumbing to the effects of the immune system.
The researchers have suggested this kind of bacterial evasion would make some vaccines less successful in the long term. Of additional concern is that pneumococcus bacteria actually comes in more than 90 varieties or serotypes, with each variety appearing slightly differently to the immune system. A vaccine against more than 90 types would not be possible, but an updated vaccine which protects against 13 types has recently been introduced. Dr Rory Bowden, one of the researchers from the University of Oxford, has said: “There are plenty of vaccines out there that look stable and continue to work because they target bacteria or viruses that are not changing.” He adds, however, that the “holy grail” would be a universal vaccine which would target something common to all types of pneumococcus.
Dr Bernard Beall, from the US Centers for Disease Control and Prevention, concludes: “The current vaccine strategy of targeting predominant pneumococcal serotypes is extremely effective, however our observations indicate that the organism will continue to adapt to this strategy with some measurable success.”
Bacteria are continually developing, and this study highlights their persistent capability to evolve in order to combat medical advances. Thankfully, infection rates from bacteria such as pneumococcus remain mercifully low in the developed world, but it is nevertheless crucial as an expatriate to ensure that you are fully covered, in the event any of these microorganisms should one day afflict you. International health insurance from William Russell is a must-have for anyone living outside of their country of origin, so click here to learn more, or click here to request a call back from one of our team.
Source – BBC News 29 Jan 12
