TIME – People vaccinated before their first case of COVID-19 are diagnosed with Long COVID significantly less often than unvaccinated people, suggests a large new study published Nov. 22 in the BMJ.
That’s not an entirely new finding. For years, studies have shown that, while vaccinated people can and do develop Long COVID, they are at lower risk than people who haven’t had their shots.
But researchers have come to drastically different estimates about exactly how much protection vaccines offer against Long COVID, with their findings ranging from about 15% efficacy to around 50%.
To reach their conclusions, they studied data from more than half a million adults in Sweden who caught COVID-19 for the first time from December 2020 to February 2022.
National vaccine records showed that about half of those people had gotten at least one COVID-19 vaccine dose before they got sick, while the others were unvaccinated.
“The trends reported in the study are promising, given that more than 5.5 billion people around the world have now received at least one dose of a COVID-19 vaccine.”
Using the participants’ health records, the researchers then assessed who went on to be diagnosed with Long COVID during the study’s follow-up period, which ended in November 2022.
The study looked only at original COVID-19 vaccines, not newer boosters like the one released this fall. It also did not assess Long COVID after reinfections, which in some cases do lead to long-lasting health problems.
As such, the findings may not translate perfectly to the present day, when many people have received updated shots and had COVID-19 multiple times.
Long COVID diagnoses were rare across the board during the study’s follow-up period, but even less common among people who’d been vaccinated before getting sick.
About 1.4% of unvaccinated people received a Long COVID diagnosis during the study period, compared to 0.4% of previously vaccinated people …