Remission of severe forms of long COVID following monoclonal antibody (MCA) infusions: A report of signal index cases and call for targeted research

Objective: Long COVID has afflicted tens of millions globally leaving many previously-healthy persons severely and indefinitely debilitated. The objective here was to report cases of complete, rapid remission of severe forms of long COVID following certain monoclonal antibody (MCA) infusions and review the corresponding pathophysiological implications. Design: Case histories of the first three index events (among others) are presented. Unaware of others with similar remissions, each subject independently completed personal narratives and standardized surveys regarding demographics/occupation, past history, and the presence and respective severity grading of 33 signs/symptoms associated with long COVID, comparing the presence/severity of those symptoms during the pre-COVID, long-COVID, post-vaccination, and post-MCA phases. Setting: Patient interviews, e-mails and telephone conversations. Subjects: Three previously healthy, middle-aged, highly-functioning persons, two women and one man (ages 60, 43, and 63 years respectively) who, post-acute COVID-19 infection, developed chronic, unrelenting fatigue and cognitive impairment along with other severe, disabling symptoms. Each then independently reported incidental and unanticipated complete remissions within days of MCA treatment. Interventions: The casirivimab/imdevimab cocktail. Measurements and main results: Irrespective of sex, age, medical history, vaccination status, or illness duration (18, 8 and 5 months, respectively), each subject experienced the same complete remission of their persistent disabling disease within a week of MCA infusion. Each rapidly returned to normal health and previous lifestyles/occupations with normalized exercise tolerance, still sustained to date over two years later. Conclusions: These index cases provide compelling clinical signals that MCA infusions may be capable of treating long COVID in certain cases, including those with severe debilitation. While the complete and sustained remissions observed here may only apply to long COVID resulting from pre-Delta variants and the specific MCA infused, the striking rapid and complete remissions observed in these cases also provide mechanistic implications for treating/managing other post-viral chronic conditions and long COVID from other variants. Key points: • Question: Considering that long COVID-19 has been devastating for many millions worldwide, what is the proposed pathophysiology and are there any effective treatments? • Findings: Previously-healthy middle-aged persons who had developed persistent debilitating post-acute SARS-CoV-2 sequelae, each experienced complete remission of their symptoms within days of receiving a specific monoclonal antibody infusion despite relative differences in sex, age, medical history, vaccination status, and long COVID duration. • Meaning: Certain monoclonal antibody infusions may be capable of reversing severe long COVID. Beyond providing an effective potential treatment for long COVID, these findings have mechanistic implications for treating other post-viral chronic conditions, including future long COVID variants.