Long COVID is a complex, multi-system illness with the potential for a substantial impact on society, from increased health care costs to economic and productivity losses. Symptoms may persist for weeks or months following acute SARS-CoV-2 infection, come and go over time, or manifest as new onset chronic conditions, such as heart disease, diabetes, kidney disease and neurological conditions.

Long COVID is an umbrella term used to describe both ongoing symptoms in the mediumterm (4–12 weeks) and longer-term sequelae beyond 12 weeks known as post-COVID syndrome (National Institute for Health and Care Excellence) or post COVID-19 condition (World Health Organization).

This review analyses the available Australian and international literature to understand the impact and scale of long COVID, including:

• incidence and prevalence of long COVID in Australia and internationally
• whether SARS-CoV-2 variants and vaccination modify the risk of developing long COVID
• demographic, clinical and social determinants of long COVID
• outcomes and impact of long COVID on patients, such as burden of disease, health service use, quality of life and patient experience
• data deficiencies and research gaps around long COVID

Many studies from the early phases of the pandemic were conducted before clear definitions were developed and produced wide variation in results. In addition, there has been no consensus on a core set of health outcomes to be measured and reported for long COVID which has also translated into inconsistent findings