According to an article in the British Medical Journal (BMJ), the likelihood of long COVID symptoms was observed to decrease after COVID-19 vaccination and evidence suggested sustained improvement after a second dose, at least over the median follow-up of 67 days.
Vaccination may contribute to a reduction in the population health burden of long covid, although longer follow-up is needed.
Presence of long COVID symptoms was at least 12 weeks after infection over the follow-up period February 3 to September 5, 2021.
Mean age of participants was 46 years, 55.6% (n=15 760) were women, and 88.7% (n=25 141) were of white ethnicity. Median follow-up was 141 days from first vaccination (among all participants) and 67 days from second vaccination (83.8% of participants). 6729 participants (23.7%) reported long covid symptoms of any severity at least once during follow-up.
Preliminary research suggests that long COVID symptoms are less common in breakthrough infections, but the effectiveness of vaccination on pre-existing long covid is less clear. Anecdotal evidence suggests variations in the lived experience of long covid after vaccination, with patients describing improvement, deterioration, and no change in their symptoms. In an online survey of members of a long COVID patient advocacy group in the US, about 40% of respondents reported full or partial symptom resolution after vaccination and 14% reported deterioration. In a similar survey conducted by a UK based patient group, more than a half of participants experienced an improvement in long covid symptoms and a fifth experienced a worsening of symptoms. Although such studies are informative, they included self-selected groups of participants who might not be representative of the population of interest and lacked control groups and long term follow-up, and other studies have included small sample sizes. A quarter of the UK population aged 12 years and older were yet to receive two doses of a covid-19 vaccine by September 5, 2021, and 16% had not received their first dose. Possible vaccine hesitancy among people with long covid symptoms has been identified through social media discourse.
Greater evidence is therefore needed on the symptomology of SARS-CoV-2 infection after vaccination, which may facilitate informed decision making among individuals with long covid. To estimate associations between COVID-19 vaccination and long covid symptoms in adults infected with SARS-CoV-2 before vaccination, we used data from the Office for National Statistics COVID-19 Infection Survey, a large, community based population survey.
The primary outcome at each visit was long COVID of any severity, with a secondary outcome of long COVID resulting in limitation of day-to-day activities (“a little” or “a lot” versus “not at all” or no long covid); this definition of functional impairment is standardized across data collections by the UK Government Statistical Service and is designed to measure disability as defined in the Equality Act 2010. We also evaluated the 10 individual symptoms that were most commonly reported over the follow-up period and whether participants were experiencing more than three or more than five of the 21 symptoms included on the survey.