Preprint Long COVID in a highly vaccinated population infected during a SARS-CoV-2 Omicron wave - Australia, 2022, 2023, Woldegiorgis et al.

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Long COVID in a highly vaccinated population infected during a SARS-CoV-2 Omicron wave - Australia, 2022
Mulu Woldegiorgis; Gemma Cadby; Sera Ngeh; Rosemary Korda; Paul Armstrong; Jelena Maticevic; Paul Knight; Andrew Jardine; Lauren Bloomfield; Paul Effler

Objective: To characterise Long COVID in a highly vaccinated population infected by Omicron.

Design: Follow-up survey of persons testing positive for SARS-CoV-2 in Western Australia, 16 July-3 August 2022.

Setting: Community Participants: 22,744 persons with COVID-19 who had agreed to participate in research at the time of diagnosis were texted a survey link 90 days later; non-responders were telephoned. Post stratification weights were applied to responses from 11,697 (51.4%) participants, 94.0% of whom had received >= 3 vaccine doses.

Main outcome measures: Prevalence of Long COVID defined as reporting new or ongoing COVID-19 illness-related symptoms or health issues 90 days post diagnosis; associated health care utilisation, reductions in work/study and risk factors were assessed using log-binomial regression.

Results: 18.2% (n=2,130) of respondents met case definition for Long COVID. Female sex, being 50-69 years of age, pre-existing health issues, residing in a rural or remote area, and receiving fewer vaccine doses were significant independent predictors of Long COVID (p < 0.05). Persons with Long COVID reported a median of 6 symptoms, most commonly fatigue (70.6%) and difficulty concentrating (59.6%); 38.2% consulted a GP and 1.6% reported hospitalisation in the month prior to the survey due to ongoing symptoms. Of 1,778 respondents with Long COVID who were working/studying before their COVID-19 diagnosis, 17.9% reported reducing/discontinuing work/study.

Conclusion: 90 days post Omicron infection, almost 1 in 5 respondents reported Long COVID symptoms; 1 in 15 of all persons with COVID-19 sought healthcare for associated health concerns >=2 months after the acute illness.

Link | PDF (Preprint: MedRxiv)

 

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There are several important findings from this investigation. First, in a highly vaccinated population exposed exclusively to the Omicron variant, almost 20% reported ongoing symptoms compatible with Long COVID at 90 days post COVID-19 diagnosis. This figure is substantially higher than the prevalence reported from a review of Australian data from earlier in the pandemic which found 5% to 9.7% of persons with SARS-CoV-2 experienced ‘post COVID condition’ at 12 weeks or more after infection.

The proportion also exceeds the those reported from large studies in the United Kingdom and Canada. The WA results are however similar to those from a recent study from Queensland, where 21% of persons diagnosed with Omicron reported ongoing symptoms at 12 weeks. Thus, while limited evidence from Australia and other countries has suggested that the risk of Long COVID may be lower among those infected with Omicron compared to previous variants, our results indicate that the burden of Long COVID 90 days after Omicron infection is substantial.

 

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Fourth, we found that almost two-thirds of persons with Long COVID who were working or studying at the time of their COVID-19 diagnosis were able to fully return to these activities within a month. Nevertheless, nearly one in five had reduced hours or were not working at 90 days post COVID-19 diagnosis. As reported elsewhere, these data highlight that in addition to negative impacts on health, there may be significant economic and workforce implications associated with Long COVID.

 

[SNT Gatchaman]

Published as —

Long COVID in a highly vaccinated but largely unexposed Australian population following the 2022 SARS-CoV-2 Omicron wave: a cross-sectional survey
Mulu Woldegiorgis; Gemma Cadby; Sera Ngeh; Rosemary J Korda; Paul K Armstrong; Jelena Maticevic; Paul Knight; Andrew Jardine; Lauren E Bloomfield; Paul V Effler

OBJECTIVES
To estimate the prevalence of long COVID among Western Australian adults, a highly vaccinated population whose first major exposure to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was during the 2022 Omicron wave, and to assess its impact on health service use and return to work or study.

STUDY DESIGN
Follow-up survey (completed online or by telephone).

SETTING
participants: Adult Western Australians surveyed 90 days after positive SARS-CoV-2 test results (polymerase chain reaction or rapid antigen testing) during 16 July – 3 August 2022 who had consented to follow-up contact for research purposes.

MAIN OUTCOME MEASURES
Proportion of respondents with long COVID (ie, reporting new or ongoing symptoms or health problems, 90 days after positive SARS-CoV-2 test result); proportion with long COVID who sought health care for long COVID-related symptoms two to three months after infection; proportion who reported not fully returning to previous work or study because of long COVID-related symptoms.

RESULTS
Of the 70 876 adults with reported SARS-CoV-2 infections, 24 024 consented to contact (33.9%); after exclusions, 22 744 people were invited to complete the survey, of whom 11 697 (51.4%) provided complete responses. Our case definition for long COVID was satisfied by 2130 respondents (18.2%). The risk of long COVID was greater for women (v men: adjusted risk ratio [aRR], 1.5; 95% confidence interval [CI], 1.4–1.6) and for people aged 50–69 years (v 18–29 years: aRR, 1.6; 95% CI, 1.4–1.9) or with pre-existing health conditions (aRR, 1.5; 95% CI, 1.4–1.7), as well as for people who had received two or fewer COVID–19 vaccine doses (v four or more: aRR, 1.4; 95% CI, 1.2–1.8) or three doses (aRR, 1.3; 95% CI, 1.1–1.5). The symptoms most frequently reported by people with long COVID were fatigue (1504, 70.6%) and concentration difficulties (1267, 59.5%). In the month preceding the survey, 814 people had consulted general practitioners (38.2%) and 34 reported being hospitalised (1.6%) with long COVID. Of 1779 respondents with long COVID who had worked or studied before the infection, 318 reported reducing or discontinuing this activity (17.8%).

CONCLUSIONS
Ninety days after infection with the Omicron SARSCoV-2 variant, 18.2% of survey respondents reported symptoms consistent with long COVID, of whom 38.7% (7.1% of all survey respondents) sought health care for related health concerns two to three months after the acute infection.

Link | PDF (Medical Journal of Australia) [Open Access]