Most mild long-Covid cases likely to return to full health within a year, research finds

Study published in BMJ finds mild Covid-19 in vaccinated people associated with reduced risk of shortness of breath compared with unvaccinated patients

Patients with mild long Covid are likely to return to full health within a year from initial diagnosis, according to new research.

The study, published in BMJ and based on patient experiences in Israel, also found that mild Covid-19 in vaccinated people was significantly associated with reduced risk for shortness of breath, compared with unvaccinated patients, up to three months after infection.

Those behind the study analysed electronic health records from the database of Maccabi Healthcare Services (MHS) in Israel and found that outcomes for those who had been vaccinated were better than for those who had not been vaccinated when they initially contracted Covid-19.

The initial population sample of more than 1.9 million people who had a Covid test between March 2020 and October 2021 was reduced to 299,885 eligible people with complete data, who tested positive for Covid-19 and who had not been admitted to hospital a month after their diagnosis.


“Our analysis showed an increased risk for several health outcomes after mild Covid-19 that was more prominent during the first six months after infection and decreased thereafter,” it said. “Data showed that the risk varied between different age groups and slightly differed between male and female patients and with vaccination status.

“The 41-60 years subgroup had the highest number of long-Covid health outcomes that were significantly elevated in both time periods during the year after infection.”

Initial infection

Long Covid is defined as symptoms persisting or new symptoms appearing more than four weeks after initial infection. A briefing paper for the Oireachtas published a year ago said an estimated 114,000 people in Ireland had the condition at that point, while a separate Irish study published last November suggested nearly 90 per cent of those living with long Covid had not returned to their pre-Covid level of health.

One of the authors of the Irish study, Dr Corinna Sadlier, said the data from Israel was a welcome development in increasing understanding of Covid-19 and its longer-term impacts.

Dr Sadlier, a consultant in infectious diseases and the Covid-19 clinical lead at Cork University Hospital, said she was seeing post-hospital Covid patients in CUH and a number of long-Covid patients at the long-Covid clinic at the St Mary’s health campus in Cork.

“I think there is a very good awareness now of long Covid as a clinical entity,” she said. “It is difficult for patients in that there is no diagnostic test.”

Dr Sadlier said one frustration among patients was the lack of pharmaceutical or therapeutic interventions, with as yet no positive results from reviews of the use of anti-viral and anti-inflammatory drugs, as well as some other medications.

“From a patient perspective that is very frustrating – it is slow. Hopefully there will be a treatment from the clinical trials that are under way.

Drivers of condition

“The other thing that we really do not understand and that we have looked at is what is actually driving the long Covid condition.”

Dr Sadlier is seeing patients who initially caught Covid in 2020, as is Prof Seamus Linnane, a consultant in respiratory and general medicine who heads up the Covid clinic at the Beacon Hospital. He estimated that the clinic had already seen approximately 1,000 patients since it began in mid-2021 and said it was booked for the coming months, even as some people were being discharged.

“The data says the odds are we work through this [long Covid] for a year or so and the odds are you will come out the other side,” he said. “It is fantastic to be able to say that to people.

“This condition is defined by an absence of pathology.

“The people who are going to come to a clinic that is around for a while are probably those who are having the hardest time.”

The latest research, which is called “Long Covid Outcomes at One Year after Mild Sars-CoV-2 Infection: Nationwide Cohort Study”, is published on Wednesday.