Long Covid Symptom Clusters, Correlates and Predictors in a Highly Vaccinated Australian Population in 2023

DOI record: { "DOI": "10.1111/hex.70273", "ISSN": [ "1369-6513", "1369-7625" ], "URL": "http://dx.doi.org/10.1111/hex.70273", "abstract": "<jats:title>ABSTRACT</jats:title><jats:sec><jats:title>Background</jats:title><jats:p>Limited data exists regarding long Covid burden following Omicron infection in highly vaccinated populations.</jats:p></jats:sec><jats:sec><jats:title>Objective</jats:title><jats:p>To (1) characterise long Covid prevalence and predictors and (2) identify key symptom clusters and their correlates among long Covid patients, during an Omicron‐predominant period in a highly vaccinated population.</jats:p></jats:sec><jats:sec><jats:title>Design</jats:title><jats:p>Anonymous, online, cross‐sectional survey.</jats:p></jats:sec><jats:sec><jats:title>Setting</jats:title><jats:p>January 2023, Australia.</jats:p></jats:sec><jats:sec><jats:title>Participants</jats:title><jats:p>Residents aged ≥ 18 years with self‐reported history of test‐positive Covid‐19.</jats:p><jats:p>The main variables studied were socio‐demographic characteristics, Covid‐19 risk factors, vaccination, infection history and experiences with long Covid.</jats:p></jats:sec><jats:sec><jats:title>Main Outcome Measures</jats:title><jats:p>Long Covid symptoms. Symptom‐based clustering was used to identify long Covid symptom clusters and their functional correlates. Predictors of long Covid occurrence and severity were assessed using multivariable logistic regression.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Overall, 240/1205 participants (19.9%) reported long Covid. Long Covid risk was significantly higher for women OR 1.71 (95% CI: 1.17–2.51), people with comorbidities 2.19 (95% CI: 1.56–3.08) and those using steroid inhalers for Covid‐19 treatment (2.34 [95% CI: 1.29–4.24]). Long‐Covid risk increased with increasing Covid‐19 infection severity (moderately severe symptoms: 2.23 [95% CI: 1.50–3.30], extremely severe symptoms: 5.80 [95% CI: 3.48–9.66], presented to ED/hospitalised: 7.22 [95% CI: 3.06–17.03]). We found no significant difference in the likelihood of long Covid between the Omicron and pre‐Omicron periods, vaccination status and participant age.</jats:p><jats:p>We identified two long Covid clusters (pauci‐symptomatic, <jats:italic>n</jats:italic> = 170, vs. polysymptomatic, <jats:italic>n</jats:italic> = 66). Polysymptomatic cluster membership was associated with worse functioning (impacts on work, moderate activity, emotions and energy). Severity acute infection was strongly predictive of polysymptomatic cluster membership (5.72 [2.04–17.58]). Monoclonal antibody treatment was strongly associated with pauci‐symptomatic cluster membership (0.02 [0.00–0.13]).</jats:p></jats:sec><jats:sec><jats:title>Discussion</jats:title><jats:p>Our study shows that long Covid is an important health burden in Australia, including during the Omicron era, and identifies several risk factors. We found a subgroup of patients characterised by more symptoms and worse functional outcomes. Our findings can inform policies for protecting vulnerable populations and frameworks for long Covid risk assessment and management.</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p>One‐in‐five people may suffer long Covid after acute Covid‐19 infection, with similar risk across age groups. Omicron variants appear not to have a lower risk compared to earlier variants in our study. A cumulative number of symptoms can help triage long Covid patients.</jats:p></jats:sec><jats:sec><jats:title>Patient or Public Contribution</jats:title><jats:p>We did not involve patients or the public in the design of the questionnaire. 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