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.

Different variants of the virus may cause specific symptoms of long Covid, a study in Italy suggests. The study involved 428 people (254 men and 174 women) with an average age of 64 who were hospitalized with Covid-19. Seventy-six percent of participants reported at least one ongoing symptom. The most common symptoms were shortness of breath and chronic fatigue (37% and 36% of patients, respectively). Participants also reported sleep problems (16%), vision problems (13%), and brain fog (13%). Women were nearly twice as likely to develop 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 sequelae. Photo: The Quynh

Several other factors may influence the lingering symptoms a person experiences after contracting SARS-CoV-2. “We’ve seen variation in symptoms throughout the pandemic, but I think it’s more complicated than the variants,” says 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 adds.

“The long Covid symptoms we’re seeing from BA.2 – the Omicron ‘stealth’ variant – are different to 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 the 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 nerve damage.