Another Reasons Vaccines Could be Useless for You

A new discovery could explain why many vaccines do not work as well for some as they do for others. Scientists showed that Mycobacterium chelonae, a common form of bacteria found in soil and water, can decrease the effectiveness of a vaccine used to prevent tuberculosis.

The researchers studied mice, some of whom had been exposed to M. chelonae and some of whom had not been. When they were subsequently given the vaccine, the mice with prior exposure to the bacteria produced higher amounts of suppressive chemical signals.

Science Daily reports:

“Then the researchers extracted certain white blood cells with known suppressive functions from both exposed and unexposed mice. After transferring these cells into separate groups of unexposed mice, they found that recipients of suppressor cells from M. chelonae exposed mice did not respond as strongly to BCG vaccine as recipients of suppressor cells from unexposed donor mice.”

This could help explain why many immunological therapies and vaccines that seem to work in the lab fall short in the real world -- common environmental exposures could be influencing how well they work.

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