COVID-19 vaccination protects against Long COVID
UK data indicates that even though vaccinated people may have breakthrough infections, they are at less risk of developing Long COVID than those who are not vaccinated.
- 19 September 2022
- 3 min read
- by Priya Joi
What is the research about?
COVID-19 vaccines protect against infection by SARS-CoV-2 infection and, even when there are breakthrough infections, they lower the risk of severe disease and death. However, whether or not vaccines can protect against the development of Long COVID, in which symptoms persist for a month or longer, has been unclear. Different studies have come to opposing conclusions.
The researchers found that receiving two COVID-19 vaccine doses, with the last at least two weeks before SARS-CoV-2 infection almost halved (a 41% decrease) the odds of developing Long COVID symptoms.
A UK study from late 2021 showed that vaccination significantly reduced the chances of getting Long COVID. A US study of armed forces veterans earlier this year indicated that the risk of developing Long COVID was 15% less than for those who had not been vaccinated, which is a lower risk reduction than other studies seemed to indicate. This new UK study sought to look at the risk of Long COVID in people who had been vaccinated compared with those who hadn’t.
What did the researchers do?
They investigated Long COVID incidence by vaccination status in a random sample of UK adults aged 18 to 69 years from April 2020 to November 2021 from data collected by the UK COVID-19 Infection Survey, run by the Office for National Statistics (ONS).
There were 3,333 eligible participants who were double-vaccinated before they were diagnosed with SARS-CoV-2 infection, and 3,090 non-vaccinated people who had also been infected were matched to these participants as controls. Those who had been vaccinated had received their second dose at least 14 days before their first SARS-CoV-2 infection.
Have you read?
In the survey, all participants were asked whether they would describe themselves as still experiencing symptoms four or more weeks after their COVID-19 infection that could not be attributed to anything else.
What did they find?
The researchers found that receiving two COVID-19 vaccine doses, with the last at least two weeks before SARS-CoV-2 infection almost halved (a 41% decrease) the odds of developing Long COVID symptoms at least 12 weeks later, compared with not being vaccinated. Persistent Long COVID symptoms were reported by 9.5% of 3,090 breakthrough SARS-CoV-2 infections and 14.6% of unvaccinated controls.
What does this mean?
The researchers acknowledge that as participants’ Long COVID status was self-reported, it is possible that a few people misclassified their symptoms or could have actually had symptoms relating to another condition. Likewise, some people may have had persistent symptoms and may not have wanted to classify themselves as such because of the stigma sometimes associated with post-viral conditions.
The study also uses data before the Omicron variant became widespread and before most people had been given booster doses of the vaccine, so it does not take these factors into account. Nevertheless, the researchers say that it indicates the value of COVID-19 vaccination.