SARS-CoV-2 variants cause different prolonged Covid-19 symptoms

More than half of people who recover from Covid-19 have persistent symptoms, known as post-acute sequelae of Covid-19 (PASC), six months after infection. Symptoms that may occur include: chest pain and shortness of breath, fatigue, loss of taste and/or smell, anxiety and depression, confusion, mental fatigue and difficulty concentrating (also known as “brain fog”), and joint pain.

A study in Italy suggests that different variants of the virus may cause specific symptoms of long Covid. The study involved 428 people (254 men and 174 women) with a median age of 64 who were infected with Covid-19 in the hospital. Accordingly, 76% of participants reported having at least one ongoing symptom. Common symptoms were shortness of breath and chronic fatigue (37% and 36% of all patients, respectively). Participants also reported sleep problems (16%), vision problems (13%), and brain fog (13%). Women were nearly twice as likely to have long Covid as men.

Statistical analysis found that patients treated with immunosuppressants like tocilizumab were six times more likely to develop long Covid symptoms. Patients given supplemental oxygen were 40% more likely.

When researchers compared patients infected between March and December 2020 (when the original variant was dominant) with patients infected between January and April 2021 (when the B.1.1.7 or Alpha variant was dominant), there were clear differences. When Alpha was dominant, muscle aches, brain fog, and anxiety or depression were more common. In contrast, loss of smell, taste changes, and hearing loss were more commonly associated with the original variant.

Doctors check and examine the health of patients with Covid-19 symptoms. Photo: The Quynh

Several other factors may influence the lingering symptoms a person experiences after contracting SARS-CoV-2. “We see variation in symptoms as we go through the pandemic, but I think it’s more complicated than the variants,” said David Strain, MD, a senior clinical lecturer at the University of Exeter Medical School in the UK. Other factors that may contribute to changes in symptoms include the impact of vaccines, behavioral changes, and changes in perceptions of the condition, he added.

“The long Covid symptoms we’re seeing from BA.2 – the stealth variant of Omicron – are different from the ones we’ve seen in Delta,” said David Strain.

Changes in early treatment may also affect long-Covid symptoms. Robert G. Lahita, MD, Ph.D., director of the Institute for Autoimmune and Rheumatologic Diseases at Saint Joseph Health, noted that patients taking tocilizumab were six times more likely to develop long-Covid.

Tocilizumab is a monoclonal antibody that blocks an immune signaling molecule called IL-6 and is used to treat rheumatoid arthritis (RA). In mid-2021, the drug was also recommended and used to treat Covid-19.

The causes of long Covid are not yet clear, but they may be related to the direct effects of the virus itself or indirect effects on mental health due to stress and factors such as lockdown and job loss. Some possible direct effects of the infection include: the virus lingering in the body, inflammation and autoimmunity, tissue damage due to low oxygen levels during the infection, and neurological damage.