Low Prevalence of Interferon alpha Autoantibodies in People Experiencing Symptoms of Post-Coronavirus Disease 2019 (COVID-19) Conditions, or Long COVID

Within a cohort of individuals with well-characterized post-coronavirus disease 2019 (COVID-19) conditions, or "long COVID," the authors identified only 2 with anti-interferon alpha 2 autoantibodies, suggesting that these antibodies are unlikely to contribute to most cases of long COVID. Interferon (IFN)-specific autoantibodies have been implicated in severe coronavirus disease 2019 (COVID-19) and have been proposed as a potential driver of the persistent symptoms characterizing "long COVID," a type of postacute sequelae of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We report that only 2 of 215 participants with convalescent SARS-CoV-2 infection tested over 394 time points, including 121 people experiencing long COVID symptoms, had detectable IFN-alpha 2 antibodies. Both had been hospitalized during the acute phase of the infection. These data suggest that persistent anti-IFN antibodies, although a potential driver of severe COVID-19, are unlikely to contribute to long COVID symptoms in the postacute phase of the infection.