Mounting evidence that vaccines reduce risk of Long COVID
Let's dig into some of the studies on this topic
Millions of people suffer from long COVID which refers to a wide range of new, returning, or ongoing health problems people may experience more than four weeks after being first infected with SARS-CoV-2. Several studies have sought to determine where vaccines lower the risk of long COVID.
The UK’s Health Security Agency conducted an analysis of eight studies on this topic and reported that six of the studies found that vaccinated people who became infected were less likely than unvaccinated patients to develop symptoms of long COVID. The remaining two studies found that vaccination did not appear to conclusively reduce the chances of developing long COVID. Another study that analyzed records of patients in the Veterans Health Administration found that vaccinated COVID patients had only a 13% lower risk than unvaccinated patients of having symptoms six months post-infection.
Other studies have found a larger effect including one out of Britain conducted among 1.2 million people which found a 50% lower risk of long COVID among vaccinated versus unvaccinated. Another study out of Britain, not yet peer-reviewed, found a 41% risk reduction among the vaccinated. Another study conducted among 240,000 COVID found that those who had received even one dose of a COVID vaccine before their infection were one-seventh to one-tenth as likely to report two or more symptoms of long COVID 12 to 20 weeks later. A recent study (not yet peer-reviewed) out of Israel supports these findings and reported that long COVID symptoms were rare among the fully vaccinated (an estimated 54%-82% risk reduction). Emerging data suggest that vaccination brings long COVID symptoms back to baseline even if a breakthrough is acquired after vaccination.
This makes sense in that vaccines reduce the viral load after a breakthrough and also create adaptive immunity against the virus. A couple of studies have even suggested that if you are unvaccinated and suffer from long COVID, getting vaccinated after infection may help ease symptoms. TL;DR: the jury is not 100% decided on this one, but emerging data support that vaccines reduce the risk of long covid.
Sources:
https://ukhsa.koha-ptfs.co.uk/cgi-bin/koha/opac-retrieve-file.pl?id=fe4f10cd3cd509fe045ad4f72ae0dfff
https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(21)00460-6/fulltext
https://www.medrxiv.org/content/10.1101/2021.11.17.21263608v1
https://www.medrxiv.org/content/10.1101/2022.02.23.22271388v1 https://www.medrxiv.org/content/10.1101/2022.01.05.22268800v2 https://www.nejm.org/doi/full/10.1056/nejmoa2109072
https://www.npr.org/sections/health-shots/2022/03/24/1088270403/long-covid-vaccines
We put together a table that maps out the studies referenced above:
Unfortunately, we can’t embed links in the image above, but you can access a live version of the table here!
Special thanks to Ilze Abersone, MS, for helping put this together (and for maintaining our entire post database).
Thank you this summary! Can you explain more about what "vaccination brings long COVID symptoms back to baseline" means — is it referring to using vaccination to reduce previous long covid symptoms, or did the study show that vaccinated, then infected people were no more likely than uninfected people to have certain symptoms associated with long covid? Also, all of these studies focused on pre-Omicron variants, right?