Participant timeline
Subjects are screened, eligibility determined, and the informed consent is completed in REDCap in the time needed by the subject; subjects are then block randomized by study site at a 1:1 ratio vaccine:placebo group, once availability of an appropriate treatment site has been determined; the randomized subjects are scheduled for treatment, baseline screening and baseline samples are taken immediately prior to treatment, weekly health surveys are completed post-treatment, blood samples are collected every 4 weeks until week 24, qPCR testing is done upon the development of symptoms during the 24-week period, and an optional extension period of another 24 weeks is available to subjects with monthly health surveys and provision of an end of the study blood sample. Cognitive sub-study participants will also have cognitive assessments and MRI at baseline, 6 months, and 2-year time points (Fig. Schedule of enrollment, interventions, and assessments. 