In a study from Cantonal Hospital St. Gallen and elsewhere, scientists found the omicron variant of SARS-CoV-2 is much less likely to lead to long COVID than the variant circulating at the start of the COVID-19 pandemic.
The Swiss study found that healthcare workers infected with the original wild-type virus were up to 67% more likely to report symptoms of long COVID than those who hadn’t had COVID-19.
However, healthcare workers whose first infection was with the omicron variant were no more likely to report long COVID symptoms than those who’d never had COVID-19.
The team also found that having omicron after a wild-type infection didn’t carry a greater risk of long COVID or fatigue than having a wild-type infection alone.
In the study, the team assessed rates of long COVID symptoms in healthcare workers infected with the wild-type SARS-CoV-2 virus, the omicron variant (BA.1) or both and compared these to uninfected controls.
The study tested 1,201 healthcare workers (81% female) with a median age of 43 from nine Swiss healthcare networks.
The participants, who were recruited between June and September 2020, underwent regular testing for COVID-19 and provided information on their vaccination status.
The most commonly reported long COVID symptoms included loss of sense of smell/taste, tiredness/weakness, burnout/exhaustion and hair loss.
The questionnaire also covered fatigue levels. The follow-up for wild-type infections was 18 months.
The team says they can only speculate as to why this was. It’s probably due to a combination of the omicron variant being less likely to cause severe illness than the wild-type virus—and immunity acquired through previous exposure to the virus, through, for example, a sub-clinical infection without seroconversion.
The team also found that reinfection—an omicron infection after a wild-type infection—didn’t carry a greater risk of long COVID or fatigue than a wild-type infection alone.
Similarly, vaccination did not affect the risk of long COVID or fatigue in those who had omicron after the wild-type virus.
These results provide reassurance to those who are contracting COVID-19 for the first time, as well as those who have already had the wild-type virus.
If you care about COVID, please read studies about Vitamin D deficiency linked to severe COVID-19, and low-sodium plant-based diets may prevent COVID-19 better.
For more information about COVID, please see recent studies about new evidence on rare blood clots after COVID-19 vaccination, and results showing zinc could help reduce COVID-19 infection risk.
The study was conducted by Dr. Carol Strahm et al and presented at the European Congress of Clinical Microbiology & Infectious Diseases.
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