People who have been vaccinated against Covid-19 are less likely to develop long Covid after catching the virus, a review of research has concluded.
A rapid review, The effectiveness of vaccination against long Covid, by the UK Health Security Agency (UKHSA) assessed the evidence available to date from 15 studies around the world.
The findings back anecdotal evidence from the time of the initial rollout of the vaccination programme last year that people with long Covid were seeing some symptoms alleviate after being vaccinated, even if sometimes only temporarily.
The latest study has suggested that, even if vaccines may not prevent someone catching Covid-19, they can reduce infection risk, illness, severity of illness and, critically, longer term or lingering symptoms.
People with Covid who received two doses of the Pfizer, AstraZeneca or Moderna vaccines or one dose of the Janssen vaccine were about half as likely as people who received one dose or were unvaccinated to develop long Covid symptoms lasting more than 28 days, the review concluded.
Vaccine effectiveness against most long Covid symptoms was highest those aged 60 years and over.
Six of the eight studies assessing the effectiveness of vaccination before Covid-19 infection suggested that those who had been vaccinated (with one or two doses) were less likely to develop symptoms of long Covid following infection.
Long Covid
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This was in the short term (four weeks after infection), medium term (12 to 20 weeks after infection) and long term (six months after infection).
In two studies that measured individual long Covid symptoms, those who were fully vaccinated were less likely to experience common symptoms in the medium or long term than those who had not been vaccinated.
These symptoms included fatigue, headache, weakness in arms and legs, persistent muscle pain, hair loss, dizziness, shortness of breath, anosmia (or loss of smell), interstitial lung disease, myalgia (or muscle ache), and other pain.
In studies examining the effect of vaccination among people with long Covid, three of four studies that compared long Covid symptoms before and after vaccination suggested more cases reported an improvement in symptoms after vaccination, either immediately or over several weeks.
There were, however, some cases in all studies who reported a worsening in symptoms after vaccination, the UKHSA said.
Dr Mary Ramsay, head of immunisation at UKHSA, said: “These studies add to the potential benefits of receiving a full course of the Covid-19 vaccination.
“For most people symptoms of long Covid are short-lived and resolve overtime. But for some, symptoms can be more severe and disrupting to their daily lives. If you’re experiencing unusual symptoms particularly for longer than four weeks after infection, you should consider contacting your GP,” she added.
Separately, a UKHSA-backed study has concluded that two doses of Covid-19 vaccine provides significant short-term protection against infection among those who had not had a previous infection.
However, this protection wanes “significantly” after six months, it added.
Unvaccinated participants who had been previously infected with Covid-19 were found to have 86% reduced risk of reinfection, when compared to the risk of primary infection in those who had no previous infection and were also unvaccinated. This protection waned to 69% after a year.
Dual protection in people who had been previously infected and subsequently double vaccinated was even greater and more durable, standing at over 90% after two doses.
This protection remained strong over a year after infection and over six months following vaccination, the study, published in the New England Journal of Medicine concluded.
The UKHSA replaced Public Health England (PHE) last autumn as part of a government shake-up of public health within England, with PHE’s role split between the agency (with a focus on responding to the pandemic) and a new Office for Health and Improvement and Disparities, which is focused on healthcare and public health more widely.
