Most long COVID symptoms subside within a year of mild infection: Study

Patients who develop long COVID after a mild bout of COVID-19 are likely to have all symptoms dissipate within 12 months, a new BMJ study suggests.
 
Authors of the large-scale retrospective cohort study, which was released this week, looked into clinical sequelae for a year after COVID-19 infection.
 
Using the records of more than 1.9 million members of an Israeli-wide public healthcare fund who did a PCR test between 1 March 2020 and 1 October 2021, they compared conditions by age, sex, SARS-CoV-2 variants, as well as vaccination status.
 
High testing frequency allowed researchers to have a ‘reliable, uninfected control group’ with people who did not test positive to the virus, they wrote.
 
They also said they took steps to limit the study only to those who had a mild illness by omitting those admitted to hospital within 30 days of infection. Researchers likewise adjusted for alcohol intake, smoking status, socioeconomic factors and pre-existing chronic conditions.
 
‘This nationwide study suggests that patients with mild COVID-19 are at risk for a small number of health outcomes, most of which are resolved within a year from diagnosis,’ the authors wrote.
 
While weakness was the most common condition after infection throughout the study time, the researchers concluded that breathlessness is the most commonly reported symptom across age groups. It is also significantly less likely to occur among vaccinated patients, they found.
 
‘Importantly, the risk for lingering dyspnoea was reduced in vaccinated patients with breakthrough infection compared with unvaccinated people, while risks of all other outcomes were comparable,’ the authors wrote.
 
The average age of the people included in the study was recorded as 25, with 51% being women.
 
‘Minor differences’ were registered between male and female patients, the researchers said. They also noted children appear less susceptible to symptoms than adults, particularly in the early stage after infection (30–180 days).
 
‘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,’ the study stated.
 
Dr Ken McCroary is a south-west Sydney GP who sits on the RACGP Expert Committee – Quality Care (REC–QC), and is currently the GP-lead on the area’s long COVID working group.
 
He told newsGP the results of the study are unsurprising.
 
‘The study is only observational, but a welcome reflection of likely reality as time passes living with COVID,’ he said.
 
‘Like locally, Israel has a high number of vaccinated individuals – still the best predictor of COVID protection in terms of disease severity, hospitalisation and death.’
 
Associate Professor Rowena Ivers, a Wollongong-based GP who also sits on the REC–QC, said the study is reassuring for GPs.
 
‘Symptoms like fatigue are very common after COVID,’ she told newsGP.
 
‘GPs can now reassure people that while these symptoms … may affect people’s ability to do their normal activities or even work, that they are likely to resolve over time, with most resolving within six months.’
 
Both GPs note the study is limited to those who had mild disease, with patients likely to have been relatively well prior to infection.
 
‘It did not include those who had severe disease, for example those admitted to ICU, [a] population likely to have more severe sequelae, so there will still be a need to multidisciplinary treatment for those people,’ Associate Professor Ivers said.
 
Dr McCroary said the study does not diminish the importance of the condition.
 
‘It shouldn’t be interpreted that we should downplay the significant post-COVID morbidity and symptoms we [are] and will be seeing – just like the other long-term chronic fatigue, vasculitis, autoimmune diseases that GPs have been managing as well over the years,’ Dr McCroary said.
 
Dr McCroary recently contributed to the ongoing Federal Parliamentary inquiry into the impacts of long COVID and repeated COVID infections, where he advocated for funding for early GP-led intervention.
 
‘GPs are the best group to be managing and leading the decision-making moving forward as we are the ones with experience in post-viral syndromes and chronic disease, and with the scale we will be doing most of the work,’ he said.
 
‘GPs need funding to best manage the post-COVID burden in team-based, GP-led practice. Early, supportive, individually focused programs with self-sufficiency are the way to go.’
 
The first public hearing of the inquiry took place last October, and it has gathered hundreds of submissions from clinicians as well as accounts from patients affected by long COVID symptoms.
 
The uniqueness of Australia’s position and the need for further research was reiterated during that first hearing.
 
Dr Irani Thevarajan, who appeared due to her role as an infectious diseases physician at the Peter Doherty Institute for Infection and Immunity, said the impact of vaccination rates need to be clearly established.
 
‘What we don’t have a lot of understanding of is the incidence of long COVID on a population level in the Australian context,’ she said at the time.
 
‘We experienced a larger burden of infection in a vaccinated population, which does make us a distinct population to other cohorts and other studies.’
 
Extreme fatigue, shortness of breath, heart palpitations, chest pain or tightness, problems with memory and concentration, and muscle pain are among symptoms the Department of Health and Aged Care (DoH) includes in its definition of long COVID, as are changes to taste and smell.
 
The DoH defines long COVID as symptoms that linger or develop four weeks after the initial infection, a description Dr McCroary says is confusing.
 
‘I prefer “post-COVID symptoms”, just like we have dealt with “post-viral syndromes” with influenza and glandular fever … that we have been managing well in general practice for decades,’ he said.
 
The DoH also currently notes that while most people recover, some people may develop long COVID and that ‘it is not yet known how long symptoms … will last’. 
 
Authors of the BMJ article say they hope to have given more detail in that area, despite noting shortcomings in their study, such as incomplete measurement within the medical records.
 
However, they cite the scale and length of the research as strengths, calling it ‘one of the longest follow-up studies in patients with mild COVID-19 to date’.
 
‘This diversity allows the findings to be generalisable to similar Western populations worldwide,’ they wrote.
 
This article was updated on 13.01.2023 to incorporate comments from Associate Professor Rowena Ivers.
 
The RACGP has published clinical resources to help GPs care for patients with post-COVID-19 conditions on its website.
 
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