Statistical analysis
The primary endpoint of the third dose study was to assess the rate of booster-induced seroconversion among patients who remained seronegative at least 28 days following standard set of FDA authorized COVID-19 vaccinations. We hypothesized that booster dosing would convert at least 30% of the enrolled seronegative patients to seropositive as defined by our institutional Clinical Laboratory Improvement Amendments (CLIA) certified SARS-CoV-2 spike IgG assay (as compared to 10% as our null hypothesis). In a pre-specified analysis, at least 26 evaluable seronegative patients were required to have sufficient power to be able to reach this assessment. A McNemar’s test was used to determine the equality of marginal frequencies for paired nominal data with the aid of a homogeneity of stratum effects test to check if the effect was the same across all levels of a stratifying variable (