Long COVID is described by the World Health Organisation as the continuation or development of new symptoms three months after the initial SARS-CoV-2 infection, with these symptoms lasting for at least two months without any alternative explanation.
The ANU study drew on nearly 71,000 participants in Western Australia (WA) who tested positive for COVID-19 from July 16, 2022, to Aug. 3, 2022.
Of the 70,876 adult participants who consented to the research, 11,697 (16.5 percent) provided complete responses provided by the researchers.
Among the respondents, 2,130 respondents (18.2 percent) satisfied the researchers’ criteria for long COVID—reporting new or ongoing symptoms or health problems 90 days after a positive SARS-CoV-2 test result.
- Long COVID risk was greater for women, people aged 50–69 years or with pre-existing health conditions, and those with two or fewer COVID-19 vaccine doses.
- Common long COVID symptoms included fatigue and concentration difficulties.
- In a highly vaccinated population not broadly exposed to earlier SARS-CoV-2 variants, 18 percent of people infected with the Omicron variant reported symptoms consistent with long COVID 90 days after infection.
- 18 percent of these people had not fully resumed previous work or study by 3 months, and 38 percent required care from general practitioners for their symptoms 2 to 3 months after infection.
Higher Risk of Developing Long COVID from Omicron Variant
Lead researcher Mulu Woldegiorgis said the results show the risk of developing long COVID from the Omicron variant is higher than originally thought.“Our finding is, however, lower than that of a recent Queensland study, which found that 21 percent of people reported ongoing symptoms twelve weeks after PCR-confirmed infections with the SARS-CoV-2 Omicron variant,” the researchers wrote.
“Despite reports that the risk of long COVID may be lower following Omicron infections than with earlier SARS-CoV-2 variants, we found that the burden of long COVID may be substantial 90 days after Omicron infections.”
Ms. Woldegiorgis added: “The risk of long COVID was greater for women and people aged 50 to 69, as well as those with pre-existing health conditions and people who’d had fewer vaccine doses.”
Additionally, the study found that 90 percent of the study participants with long COVID reported experiencing multiple symptoms, such as tiredness and fatigue (70 percent), followed by difficulty thinking or concentrating (“brain fog”), sleep problems, and coughing.
A third of women with long COVID also reported changes in their menstrual cycle.
“More than a third of individuals with persistent long COVID—38 percent—had sought medical care in the month prior to the survey,” she said.
“This most frequently involved a visit to a GP, hospitalisations or trips to the emergency department were thankfully less common.”
The study also found that 64 percent of participants with long COVID were able to fully return to work or study within a month of their infection, but 18 percent reported still not being well enough to do so three months after their infection.
Link Between Vaccination and Long COVID
While the above study did not look at the link between vaccination and the development of long COVID, a study by Germany’s Martin Luther University Halle-Wittenberg has shown that unvaccinated people infected with the Omicron variant had the lowest risk of long COVID.The study found that while previous infections reduce the risk of long COVID by 86 percent, vaccination status prior to COVID infection is irrelevant to a person’s risk of developing long COVID.
However, the authors of the German study acknowledged that none of the participants were given an actual diagnosis of long COVID or tested for comorbidities.
