The impact of social distancing measures on anti-JC virus serostatus changes before and during the COVID-19 pandemic in US patients with multiple sclerosis.

Background: The coronavirus disease 2019 (COVID-19) pandemic offered an epidemiological opportunity to evaluate if isolation and masking affected John Cunningham (JC) virus transmission.
Objective: This study aimed to assess the proportion of natalizumab-treated patients who converted to a positive anti-JCV antibody serostatus before and during the pandemic.
Methods: Data from TYSABRI Outreach: Unified Commitment to Health (TOUCH) for 22,375 US patients treated with natalizumab with anti-JCV antibody records were assessed in epochs annually from 2017 to 2022.
Results: Pre-pandemic anti-JCV antibody serostatus change was observed for 7.4%-7.7%. During the first and second years of the pandemic, 7.3% and 7.2% of patients' serostatus changed, respectively.
Conclusion: The proportion of patients with anti-JCV antibody serostatus change did not significantly differ during the first 2 years of the pandemic compared with prior years. In contrast to seasonal influenza, masking and social distancing had no discernable effect on JCV serostatus change.
Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: S.C.K. reports consulting or advisory work with Biogen, EMD Serono, Genentech, Genzyme/Sanofi, Novartis, Octave, and TG Therapeutics; nonpromotional speaking with Biogen, EMD Serono, and Genentech; grant and research support from Biogen, Bristol Myers Squibb (BMS), Novartis, and Sanofi. S.S., F.H., J.S., T.J.K., K.W., and R.L.A. are the employees of and may hold stock and/or stock options in Biogen.