Published: 30 May 2022
An NIHR-supported study of more than 28,000 people has shown that vaccination against COVID-19 is associated with a moderate reduction in the risk of experiencing long COVID.
The study found that a first vaccine dose reduced the likelihood of long COVID symptoms by more than 12% in people who had tested positive for COVID-19 before vaccination. A second dose was associated with a further 9% reduction in the odds of long COVID.
Some people who get COVID-19 experience symptoms that last weeks or months after the infection has gone, a condition known as post-COVID-19 syndrome or 'long COVID'. Preliminary research suggests that people who get COVID-19 after vaccination are less likely to have symptoms long COVID, but the effectiveness of vaccination on pre-existing long COVID symptoms is less clear.
A team of academics and government statisticians supported by NIHR Applied Research Collaboration (ARC) East Midlands and NIHR Leicester Biomedical Research Centre assessed data from the Office for National Statistics’ COVID-19 Infection Survey between 3 February and 5 September 2021.
Their analysis looked at the health outcomes of 28,356 people who had caught coronavirus and later received a vaccine. More than 23% of the participants had symptoms of long COVID 12 weeks or more after they were infected with the virus, and 18% had symptoms that limited their activities.
The research found that a first vaccine dose initially reduced the risk of long COVID symptoms by 12.8%, with a second jab reducing the likelihood of symptoms by a further 8.8%. Further modelling showed that the decrease after a first vaccination might wear off but the reduction after a second dose seemed to be sustained, at least over the median follow-up of 67 days.
In addition, the research reported that there was no evidence of association between vaccination and long COVID by sociodemographic characteristics, health status, hospital admission with acute COVID-19, vaccine type or duration from infection to vaccination.
Researcher Daniel Ayoubkhani, a PhD student funded by NIHR ARC East Midlands, said: “With nearly 2 million people in the UK currently experiencing ongoing symptoms after SARS-CoV-2 infection, our results suggest that vaccinating people previously infected may be associated with a reduction in the burden of long COVID on population health, at least in the first few months after vaccination.
“Further research is required to evaluate the long-term relationship between vaccination and long COVID, in particular the impact of the omicron variant, which has become dominant in the UK.”
Professor Kamlesh Khunti CBE, Director of NIHR ARC East Midlands, said: “The findings have reported that people with long COVID who experience dysregulation of the immune system may benefit from autoimmune processes being reset by vaccination. Any residual viral reservoir may also be destroyed by the antibody response.”
He concluded: “More research into this area is needed to understand the biological mechanisms underpinning any improvements in symptoms after vaccination, which may contribute to the development of therapeutics for Long COVID.”
The study has been published in the British Medical Journal.