A large UK study in BMJ suggests that COVID-19 vaccination after infection lowers the odds of persistent symptoms, with a 12.8% initial decline after the first dose and an 8.8% drop after the second—although the long-term effects are unclear.Published this week, the observational study included 28,356 participants aged 18 to 69 years in the Office for National Statistics COVID-19 Infection Survey who had received one or more doses of the AstraZeneca/Oxford adenovirus vector or the Pfizer/BioNTech or Moderna mRNA vaccines after COVID-19 infection.The team, led by researchers from the Office for National Statistics, monitored participants from Feb 3 to Sep 5, 2021, to identify those with COVID-19 infections and symptoms lasting at least 12 weeks.
The study period spanned the emergence and dominance of the SARS-CoV-2 Delta variant but preceded the emergence of Omicron.Participants answered survey questions and underwent COVID-19 polymerase chain reaction (PCR) testing once weekly for 1 month and then monthly for a year or longer, and those in households in which a household contact had tested positive for COVID-19 were asked to provide monthly blood samples for SARS-CoV-2 antibody testing.Average participant age was 46 years, 55.6% were women, and 88.7% were White.
Follow-up was a median of 141 days after the first COVID-19 vaccine dose for all participants and 67 days after the second dose for the 83.8% who received both doses.Lower odds of long COVID after first doseAmong the 28,356 participants, 23.7% reported long COVID symptoms of any severity once or more during follow-up.
One vaccine dose was tied to an initial 12.8% reduction in the likelihood of long COVID, followed by increases and decreases (0.3% weekly; 95%