Great British study in BMJ It indicates that post-infection COVID-19 vaccine reduces the odds of persistent symptoms, with an initial decrease of 12.8% after the first dose and 8.8% after the second — although the long-term effects are unclear.
This week published the observational study of 28,356 participants aged 18 to 69 years in the Office for National Statistics COVID-19 Infection Survey who received one or more doses of the AstraZeneca/Oxford adenovirus vector, Pfizer/BioNTech vaccines, or Moderna mRNA after infection with COVID-19.
The team, led by researchers from the Office for National Statistics, monitored participants from February 3 to September 5, 2021, to identify those with COVID-19 infection and their symptoms that lasted at least 12 weeks. The study period extended the emergence and dominance of the delta variant of SARS-CoV-2 but predated the emergence of Omicron.
Participants answered survey questions and underwent a polymerase chain reaction (PCR) test for COVID-19 once weekly for one month and then monthly for a year or more, and people in households where a family member tested positive for COVID-19 were asked to provide blood samples Monthly SARS-CoV-2 antibody test.
The average age of the participants was 46 years, 55.6% were women, and 88.7% were white. Follow-up was a mean of 141 days after the first COVID-19 vaccine dose for all participants and 67 days after the second dose for 83.8% who received both doses.
Reducing the risk of infection with the Covid virus for a long time after the first dose
Among 28,356 participants, 23.7% reported prolonged COVID symptoms of any severity one or more times during follow-up. A single vaccine dose was linked to an initial 12.8% reduction in the likelihood of long-term COVID-19 infection, followed by increases and decreases (0.3% weekly; 95% confidence interval). [CI]-0.6% to 1.2%).
A second dose of the vaccine was linked to an initial 8.8% (95% CI, -14.1% to -3.1%) reduction in the risk of persistent symptoms, and a 0.8% weekly reduction (95% CI, -1.2% to -0.4%) thereafter. Outcomes did not differ by sociodemographic factors, health status, hospitalization for primary infection, type of vaccine, or time from diagnosis to vaccination.
Among all participants, 16.7% reported that prolonged COVID symptoms limited their ability to participate in activities at least once during follow-up. The first vaccine dose was associated with a 12.3% (95% CI, 19.5% to −4.5%) reduction in the chances of prolonged activity limitation from COVID effects (0.9% per week; 95% CI, 0.2% to 1.9%) until a dose was taken. a second. A second dose was associated with an initial 9.1% (95% CI, 15.6% to −2.1%) decrease in the likelihood of prolonged COVID activity reduction, followed by a 0.5% weekly decrease (95% CI, −1.0% to 0.05%) until Post follow up.
Long-term risk of developing COVID-19 after the first dose of the COVID-19 vaccine decreased over time from infection, by 24.8%, 16.5%, and 4.8% for participants who received their first dose 9, 12, and 15 months after diagnosis.
The likelihood of experiencing most symptoms, as well as more than three or five symptoms at a time, decreased after each vaccination, with the largest reductions in loss of smell (−12.5%), loss of taste (−9.2%), and lack of sleep (8.8%) . After the second dose, the greatest reduction in fatigue (9.7%), headache (−9.0%) and poor sleep (9.0%) occurred.
The likelihood of experiencing most single symptoms and more than three or five symptoms at once decreased after the first dose. Trends were mostly positive between the first and second doses, but most returned to a downward or steady trend after the second.
Obvious interpretation of “still lacking”
“People with prolonged COVID-19 who have a dysregulated immune system may benefit from resetting their autoimmune processes by vaccination (although it remains to be determined whether this persists for a prolonged period or not), while the also destroy any remaining viral reservoir through the antibody response, the authors wrote.
They concluded that while the observational nature of the study precludes the establishment of a causal relationship, “vaccination may contribute to a prolonged reduction in the population health burden of coronavirus.”
In a related editorial, Manoj Sivan, MD, from the University of Leeds in England; Trisha Greenhalgh, MD from Oxford University; Roered Millen, MBBS from the University of Southampton; Brendan Delaney, BMBCh, from Imperial College London, said the results show that vaccination is likely to avoid COVID for a long time in only a low percentage of patients.
“There is still a lack of a clear explanation of how vaccines reduce the multisystem manifestations of the prolonged Covid-19 virus,” they wrote. “Especially for people who are already past the stage of systemic inflammatory responses, and those with end-organ damage from COVID-19, such as lung fibrosis.”
While the benefits of vaccination outweigh the potential risks and are especially important for long-term COVID patients, Sevan and colleagues said that much remains unknown about the effects of repeated infections or booster doses and their long-term prognosis.