Long <scp>COVID</scp> in a highly vaccinated but largely unexposed Australian population following the 2022 <scp>SARS‐CoV</scp>‐2 Omicron wave: a cross‐sectional survey
Mulu Abraha Woldegiorgis, Gemma Cadby, Sera Ngeh, Rosemary Korda, Paul Armstrong, Jelena Maticevic, Paul R. Knight, Andrew Jardine, Lauren Bloomfield, Paul V. Effler
Abstract
OBJECTIVE: 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%). CONCLUSION: Ninety days after infection with the Omicron SARS-CoV-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.