Vaccination against COVID-19, whether administered before or after infection, reduces the risk of symptoms of long COVID

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People who have been vaccinated against COVID-19 are less likely to develop long COVID symptoms if they go on to become infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) compared with those who were unvaccinated, according to a rapid review of evidence.

Also, individuals who undergo vaccination following infection are more likely to experience symptoms of long COVID for a shorter time than those who do not receive a vaccine, an investigation by the UK Health Security Agency (UKHSA) has found.

Two doses of a COVID-19 vaccine are more protective than one dose, it said.

An estimated 2.1% of the UK population have reported symptoms of long COVID, according to figures released earlier this month by the Office for National Statistics.

Dr Mary Ramsay, Head of Immunisation at the UKHSA, said that their findings ‘add to the potential benefits of receiving a full course of the COVID-19 vaccination.’

Vaccination before infection

The research was based on 15 international studies that looked at the effectiveness of vaccination against long COVID, four of which were conducted in the UK.

Seven of the studies examined whether vaccination before infection reduced the symptoms or incidence of long COVID. Most of these studies suggested that people who had received one or two doses of a vaccine were less likely to develop symptoms of long COVID in the short, medium, and long term—covering 4 weeks to 6 months—than those who were unvaccinated.

The data also suggested that people with COVID-19 who received two doses of the Pfizer/BioNTech, AstraZeneca/Oxford University, or Moderna vaccines, or one dose of the Janssen vaccine, were approximately half as likely as people who received one dose, or were unvaccinated, to develop long COVID symptoms lasting more than 28 days.

Vaccine effectiveness against most post-COVID-19 symptoms in adults was highest in people aged 60 years and over, and lowest for younger participants aged 19–35 years.

Later vaccination 

Seven of the studies examined what happened to people who already had symptoms of long COVID who were subsequently vaccinated.

Three studies suggested that more people who had long COVID said that their symptoms improved, rather than worsened, after vaccination, either immediately or over several weeks.

One study, which examined the timing of vaccination after infection with SARS-CoV-2, suggested that people with COVID-19 who were vaccinated sooner after diagnosis were much less likely to report long COVID symptoms than those who remained unvaccinated.

One small UK study found that, of participants who reported having long COVID, 23.2% of vaccinated people said that their symptoms improved, compared with 15.4% of unvaccinated individuals.

Importance of vaccination 

Commenting for the Science Media Centre, Deborah Dunn-Walters, Chair of the British Society for Immunology COVID-19 Taskforce and Professor of Immunology at the University of Surrey, described the analysis as ‘comprehensive.’

She said: ‘This review re-emphasises the importance of everyone, no matter their age, getting vaccinated against COVID-19. Vaccination is the safest and most effective way to protect yourself from falling sick with COVID-19 and suffering from long COVID post infection. 

‘Although there has been a high uptake of the vaccines in the UK so far, a significant number of people still need to come forward for a first or second dose.’

This article originally appeared on Medscape, part of the Medscape Professional Network.

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