There is no evidence that an individual is worse off for having avoided earlier infection.
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The discussion swirling around immunity debt shows how easy it is for a plausible-sounding theory to circulate as misinformation. In this case, misinformation risks promoting the unfounded assertion that infections are clinically beneficial to children, as well as feeding the revisionist narrative that Covid measures did more harm than good.
Professor Peter Openshaw, a respiratory doctor and immunologist who studies RSV and flu at Imperial College London, says the current “high and unseasonal” RSV wave is assumed to be a result of lockdowns causing levels of immunity to wane in children, parents and carers, paving the way for a greater number of infections.
But to frame this as an immunity debt, Openshaw warns, mistakenly suggests “that immunity is something we need to invest in, and that by protecting ourselves from infection we are building up a deficit that has ultimately to be repaid. This would not be a good message for public health: we would still have open sewers and be drinking from water contaminated with cholera if this idea were followed to its logical conclusion.”
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There is no evidence that an individual is worse off for having avoided earlier infection. “Immunity debt as an individual concept is not recognised in immunology,” Dunn-Walters says. “The immune system is not viewed as a muscle that has to be used all the time to be kept in shape and, if anything, the opposite is the case.” The constant onslaught of common pathogens such as cytomegalovirus, she adds, means the immune system begins to malfunction and slacken with age. She rejects the idea that infection is somehow good for health, saying vaccination is a far safer way of building population immunity.
23 November 2022
