Trajectory of long covid symptoms after covid-19 vaccination: community based cohort study, 2022, Ayoubkhani et al

Abstract

Objective To estimate associations between covid-19 vaccination and long covid symptoms in adults with SARS-CoV-2 infection before vaccination.

Design Observational cohort study.

Setting Community dwelling population, UK.

Participants 28 356 participants in the Office for National Statistics COVID-19 Infection Survey aged 18-69 years who received at least one dose of an adenovirus vector or mRNA covid-19 vaccine after testing positive for SARS-CoV-2 infection.

Main outcome measure Presence of long covid symptoms at least 12 weeks after infection over the follow-up period 3 February to 5 September 2021.

Results 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. A first vaccine dose was associated with an initial 12.8% decrease (95% confidence interval −18.6% to −6.6%, P<0.001) in the odds of long covid, with subsequent data compatible with both increases and decreases in the trajectory (0.3% per week, 95% confidence interval −0.6% to 1.2% per week, P=0.51). A second dose was associated with an initial 8.8% decrease (95% confidence interval −14.1% to −3.1%, P=0.003) in the odds of long covid, with a subsequent decrease by 0.8% per week (−1.2% to −0.4% per week, P<0.001). Heterogeneity was not found in associations between vaccination and long covid by sociodemographic characteristics, health status, hospital admission with acute covid-19, vaccine type (adenovirus vector or mRNA), or duration from SARS-CoV-2 infection to vaccination.

Conclusions 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.

Open access, https://www.bmj.com/content/377/bmj-2021-069676

 

Editorial: Are vaccines a potential treatment for long covid?, Sivan, Greenhalgh et al

Benefits are possible, but we need more evidence and a mechanism of action

Vaccines in the covid-19 pandemic have been a game changer in reducing rates of SARS-CoV-2 infection and hospital admission for, and death with, covid-19. They also reduce the chance of developing long covid by about half among people who are vaccinated before they develop covid-19.1 However, the effect of vaccines for people who already have long covid is a contentious area for both patients and healthcare professionals. In a linked paper, Ayoubkhani and colleagues (doi:10.1136/bmj-2021-069676) report findings from the largest published study on this topic to date.2 From a random sample of the UK population, they identified 28 356 adults (18-69 years) who were vaccinated after a positive SARS-CoV-2 test result, of whom 6729 (23.7%) reported long covid symptoms (>12 weeks) of any severity at least once during follow-up. Participants were followed for seven months to determine the relationship between vaccination, long covid, and symptom profiles after the first and second dose of either an adenovirus vector or mRNA vaccine.2

In an interrupted time series model adjusting for prespecified covariates, the authors found a 12.8% reduction in the odds of reporting long covid immediately after the first vaccine dose, but this reduction was not sustained over the following 12 weeks. However, an 8.8% reduction in the odds of long covid after a second dose was sustained over the next nine weeks. The authors suggested inadequate immune response as a reason for lack of sustained effect after the first dose.

Open access, https://www.bmj.com/content/377/bmj.o988

 

One thing that bothers me, and this study is no exception, is that the vaccines' efficacy clearly attenuate over the course of a few months. But with the regular vaccine schedule, until recently, all studies were on recently vaccinated people, simply because that's how the timeline happened.

So what about the efficacy over time of reducing the odds of LC? That doesn't ever seem to be taken into account adequately. They discuss it in this study but used a standardized 67 days after vaccination for everyone so it's not possible to tell.

 

COVID-19 vaccination associated with reduced risk of long COVID

https://www.nihr.ac.uk/news/covid-19-vaccination-associated-with-reduced-risk-of-long-covid/30703