Vaccination towards SARS-CoV-2 lowers the chance of lengthy COVID after an infection by solely about 15%, in accordance with a research of greater than 13 million people1. That’s the most important cohort that has but been used to look at how a lot vaccines shield towards the situation, however it’s unlikely to finish the uncertainty.

Lengthy COVID — sickness that persists for weeks or months after an infection with SARS-CoV-2 — has proved troublesome to check, not least as a result of the array of signs makes it arduous to outline. Even discovering out how frequent it’s has been difficult. Some research have instructed that it happens in as many as 30% of individuals contaminated with the virus. However a November research of about 4.5 million folks handled at US Division of Veterans Affairs (VA) hospitals means that the quantity is 7% general and decrease than that for many who weren’t hospitalized.

One other thriller has been whether or not lengthy COVID is much less prone to happen after a breakthrough an infection — one in an individual who has been vaccinated. In a 25 Might research in Nature Medication, nephrologist Ziyad Al-Aly at VA Saint Louis Well being Care System in St Louis, Missouri, and his colleagues — the identical workforce that authored the November research — checked out VA well being data from January to December 2021, together with these of about 34,000 vaccinated individuals who had breakthrough SARS-CoV-2 infections, 113,000 individuals who had been contaminated however not vaccinated and greater than 13 million individuals who had not been contaminated.

Chinks within the armour

The researchers discovered that vaccination appeared to cut back the probability of lengthy COVID in individuals who had been contaminated by solely about 15%. That’s in distinction to earlier, smaller research, which have discovered a lot larger safety charges. It’s additionally a departure from one other giant research, which analysed self-reported information from 1.2 million UK smartphone customers and located that two doses of a COVID-19 vaccine halved the chance of lengthy COVID.

The authors of the most recent research additionally in contrast signs comparable to mind fog and fatigue in vaccinated and unvaccinated folks for as much as six months after they examined optimistic for SARS-CoV-2. The workforce discovered no distinction in sort or severity of signs between those that had been vaccinated and those that had not. “Those self same fingerprints we see in individuals who have breakthrough infections,” Al-Aly says.

There have been greater than 83 million COVID-19 infections in the USA alone, he notes. If even a small proportion of these flip into lengthy COVID, “that’s a staggeringly excessive variety of folks affected by a illness that continues to be mysterious”.

The restricted safety offered by vaccines implies that withdrawing measures comparable to masks mandates and social-distancing restrictions could be placing extra folks in danger — notably these with compromised immune techniques. “We’re actually solely reliant, now nearly solely, on the vaccine to guard us and to guard the general public,” says Al-Aly. “Now we’re saying it’s solely going to guard you 15%. You stay weak, and terribly so.”

“Typically talking, that is horrifying,” says David Putrino, a bodily therapist at Mount Sinai Well being System in New York Metropolis who research lengthy COVID. He praises the research, which was troublesome to carry out due to the quantity and high quality of information, however provides that it’s restricted as a result of it doesn’t break the info down by key elements, such because the contributors’ medical historical past. “These are crucial questions we’d like solutions to,” Putrino says. “We don’t have any rather well constructed research simply but.”

One other Omicron unknown

Steven Deeks, an HIV researcher on the College of California, San Francisco, factors out that the research consists of no information from folks contaminated throughout the interval when the Omicron variant was inflicting the vast majority of infections. “Now we have no information on whether or not Omicron causes lengthy COVID,” he says. The findings, he provides, “apply to a pandemic that has modified dramatically”.

Nevertheless, Deeks provides, the outcomes do level to the necessity for extra analysis on lengthy COVID, and for accelerated improvement of therapies. “We don’t have a definition, we don’t have a biomarker, we don’t have an imaging check, a mechanism or a remedy,” he says. “We simply have questions.”

This text is reproduced with permission and was first printed on Might 25 2022.

By 24H

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