A new study out of Switzerland has found that health care workers infected with the COVID-19 Omicron variant were far less likely to experience long COVID symptoms than those who contracted the original SARS-CoV-2 virus. The results, which will be presented at the European Congress of Clinical Microbiology & Infectious Diseases conference in April and have been peer reviewed, showed that those infected with the original “wild-type” virus circulating in the early months of the pandemic still had persistent post-COVID symptoms 18 months later. Meanwhile, the chances of developing long COVID among workers whose first infection was with Omicron did not appear to be greater than those who had never contracted COVID-19.
Principal Investigator of the study Philipp Kohler noted that the study was conducted in a young and healthy population, and the risk of long COVID after Omicron infection was very low. This is in line with previous research, such as one article published in The Lancet which showed the risk of long COVID was lower with Omicron compared with the Delta variant, and another study published in Nature Communications which saw lower risks of long-term symptoms with Omicron 3 months after testing positive.
The Swiss study tracked 1,201 health care workers from nine domestic health care networks to examine the long-term effects of the virus. Participants completed online questionnaires three times over the next two years and reported eighteen symptoms, including loss of smell or taste, tiredness and weakness, burnout and exhaustion, and hair loss. The results of the study showed that those who tested positive with the original virus had a 67% higher risk of developing long COVID symptoms when surveyed in March 2021 compared with the control group of participants who remained uninfected.
Going forward, the Swiss team plans to continue following up with participants to see whether those infected with the original strain are still reporting symptoms nearly three years later. Infectious disease specialist Carol Strahm noted that the risk of long COVID with Omicron could be due to it being less likely to cause severe illness than the original virus, as well as immunity acquired through previous exposure, including asymptomatic infections.
It is important to note that the sample size used in the study was not very large and that the group studied is not reflective of the broader general population. Therefore, the effects of the virus in the elderly, those with other health issues, and the unvaccinated may not be the same.