As the latest Covid-19 Omicron surge starts to recede, there could be a spike in the number of patients affected by long Covid, the persistence over a period of 12 weeks or more of physical and neuropathic symptoms. There is evidence that about 14–30% of people with Covid-19 will go on to experience long Covid, which includes symptoms such as fatigue, shortness of breath, fevers, gastrointestinal issues, sleep disorders, ‘brain fog’, anxiety, post-traumatic stress disorder (PTSD) and depression. These patients could be burdened with these symptoms for months to years, though we do not know if the burden is the same for the Omicron variant as it is for the previous variants.
The Omicron variant often results in a milder disease outcome. Despite this, mild cases of Covid-19 can lead to long Covid and the majority of long Covid patients had a mild infection, though this could be due to there being more mild cases of Covid-19 than severe cases. Prolonged symptoms can also develop after asymptomatic Covid-19. There are currently no data that indicate the Omicron variant increases the chance of symptoms persisting.
There is some evidence that vaccinations can reduce the chance of developing persistent symptoms in the case of breakthrough infections. Mobile application data from a study of UK adults indicated that around 11% of unvaccinated patients had lingering symptoms for at least 28 days, compared with 5% of vaccinated individuals. This risk reduction of more than one half is promising as the number of vaccinated individuals has increased to more than four billion, according to GlobalData’s Coronavirus Disease 2019 Epidemiology Dashboard. Vaccines could help reduce these long-term care costs for Covid-19 patients.
Understanding the mechanism of long Covid will prove crucial to helping treat these patients. A recent study by the New South Wales Kirby Institute has indicated that the disease may be caused by sustained inflammation and activation of the immune system, which can last for at least eight months after the initial infection. The researchers detected six proinflammatory cytokines involved in the innate immune response that were elevated in long Covid patients. This knowledge could help provide paths to treating and diagnosing prolonged symptoms, which could bring some relief to patients suffering from them.