Large UK study suggests vaccination helps treat long COVID

An observational study in the UK has found evidence that COVID-19 vaccination can help alleviate the lingering symptoms that afflict some people who contract the virus, often referred to as 'long COVID'.

There have been persistent anecdotal reports that vaccines can help people with persistent symptoms get better, but the study published in the British Medical Journal is the first to explore the connection in large numbers of patients.

It is based on responses from more than 28,300 adults who are taking part in the UK's COVID-19 Infection Survey, carried out by the Office for National Statistics, and focused on individuals who reported symptoms that lasted for 12 or more weeks after infection.

The likelihood of long COVID symptoms was found to decrease after COVID-19 vaccination, and evidence pointed to an even greater improvement after a second dose. However, the authors say more data is needed before vaccination can be considered a treatment for the condition.

The team, led by ONS' Daniel Ayoubkhani, found that before vaccines were available, the chances of experiencing long COVID were fairly constant after infection, but fell around 13% after a first dose, and a further 9% after a second.

The trial completed before the third booster doses were rolled out, and researchers say there is no data yet on whether the improvements reported after vaccines will be sustained with further follow-up.

They speculate that vaccination may "reset" immunity in people with long COVID who are thought to develop dysregulation of the immune system, similar to an autoimmune condition.

"Although causality cannot be inferred from this observational evidence, vaccination may contribute to a reduction in the population health burden of long COVID," says the paper.

Further research is needed to look at the long-term relationship between vaccines and long COVID, and to gauge the effect of boosters and reinfection with SAS-CoV-2, particularly with the now-dominant Omicron variant, which had not emerged when the data was collected, according to the researchers.

Commenting on the results, Prof Penny Ward, visiting professor in pharmaceutical medicine at King's College London, said: "These data broadly support prescribers encouraging patients with 'long COVID' to be vaccinated, or to complete the course of vaccination if they have not already done so."

Meanwhile, Dr Peter English, a retired consultant in communicable disease control, said it is likely that long COVID is, in fact, a collection of different conditions, only some of which may respond to vaccination.

"The large scale of this study means that we can be fairly confident about what has been observed; but it does not mean we can be sure what it means," he cautioned.

Nevertheless, faced with the potentially very significant consequences the condition could have on the health of the population, "anything that can reduce the burden of disease from Long COVID at reasonable cost is…important and valuable".