The author is a science commentator
Respiratory syncytial virus is a little-known and hard-to-spell seasonal scourge that, like flu, most significantly impacts kids and older individuals. It normally triggers coughs and colds however could cause severe respiration difficulties in a small minority of infants.
RSV is so frequent that greater than 80 per cent of UK kids are contaminated by their second birthday — however case numbers plummeted through the Covid-19 pandemic. Measures similar to masking, plus college and nursery closures, supposed to gradual the unfold of Covid, additionally put the brakes on an infection charges. Now the virus is resurgent, notably within the US, with the wave hitting sooner than anticipated.
That has fuelled hypothesis that pandemic mitigations, together with lockdowns, created a dangerous “immunity debt”, with kids left susceptible by a scarcity of publicity to the standard reduce and thrust of viral infections. However scientists have dismissed the idea, as utilized to particular person immunity, as misguided.
The dialogue swirling round immunity debt exhibits how straightforward it’s for a plausible-sounding concept to flow into as misinformation. On this case, misinformation dangers selling the unfounded assertion that infections are clinically helpful to kids, in addition to feeding the revisionist narrative that Covid measures did extra hurt than good.
Professor Peter Openshaw, a respiratory physician and immunologist who research RSV and flu at Imperial Faculty London, says the present “excessive and unseasonal” RSV wave is assumed to be a results of lockdowns inflicting ranges of immunity to wane in kids, mother and father and carers, paving the way in which for a larger variety of infections.
However to border this as an immunity debt, Openshaw warns, mistakenly suggests “that immunity is one thing we have to spend money on, and that by defending ourselves from an infection we’re build up a deficit that has in the end to be repaid. This could not be message for public well being: we might nonetheless have open sewers and be ingesting from water contaminated with cholera if this concept have been adopted to its logical conclusion.” Delaying RSV an infection may very well be helpful, he provides, because the virus is deadliest to infants youthful than six months. Globally amongst under-fives, one in 50 deaths is attributable to RSV.
Deborah Dunn-Walters, professor of immunology on the College of Surrey, says it’s crucial to tell apart between particular person and inhabitants immunity (herd immunity) when scrutinising how pandemic measures might have altered the unfold of non-Covid ailments. A smaller pool of individuals being contaminated through the pandemic can lead, after the lifting of measures, to a much bigger pool of inclined individuals. That fall in inhabitants immunity can gas a surge just because there are extra individuals out there to be contaminated (different components, together with the climate and virus severity, can even have an effect on transmission).
However there isn’t a proof that a person is worse off for having averted earlier an infection. “Immunity debt as a person idea shouldn’t be recognised in immunology,” Dunn-Walters says. “The immune system shouldn’t be seen as a muscle that must be used on a regular basis to be stored in form and, if something, the other is the case.” The fixed onslaught of frequent pathogens similar to cytomegalovirus, she provides, means the immune system begins to malfunction and slacken with age. She rejects the concept an infection is in some way good for well being, saying vaccination is a far safer means of constructing inhabitants immunity.
Stephen Griffin, a virologist at Leeds College who believes paediatric pandemic vaccines have been underused, argues we’re nonetheless too complacent about childhood respiratory ailments. Whereas there isn’t a vaccine for RSV, Griffin acknowledges, “we can vaccinate in opposition to each flu and Covid — and but we don’t.” Altering that norm, he says, may assist to neuter the worst results of a predicted “tripledemic” this winter. The UK Well being Safety Company advises that eligible kids ought to obtain the flu vaccine.
The immunity debt concept holds broad attraction as a result of it may be employed in so some ways. It appears to intuitively clarify the present wave of respiratory sickness. It’s enticing to those that would downplay illness in kids, and those that advocate for an infection over vaccination. It gives a post-hoc justification for opposing measures similar to masking, despite the fact that proof means that such measures curbed Covid and nearly banished flu.
Immunity debt additionally performs to the concept the ebb and circulation of childhood sicknesses are greatest left to nature — till one remembers that your complete childhood vaccination schedule is about preserving the worst of nature at bay.