Table 2, where the index patient was seated, had very high average infection risks for all serving pathways because the other diners at that table had the opportunity to shake hands with the index patient, during which large amounts of noroviruses were transmitted. The infection risk distribution patterns at other tables were consistent with the waiters’ pathways. In Pathways 1 and 2 (Figure 2A and Figure S1A, respectively), wherein the waiters served guests at one table after another, the average infection risks of diners at each table (except Table 2) decreased according to the pathway direction (Figure 2B and Figure S1B, respectively). In Pathways 3 and 4 (Figure 2C and Figure S1C, respectively), the waiters served guests at half of a table after another half, resulting in a considerable diversity of infection risks among diners at the same table of Tables 3–5. Therefore, the average infection risks at Tables 3–5 were similar to that of Table 6. Because the diners at Table 1 were visited by waiters either very early (Pathway 3) or very late (Pathway 4), the average infection risk at that table was accordingly either very high (Figure 2D) or very low (Figure S1D). In Pathways 5 and 6 (Figure 2E and Figure S1E, respectively), wherein each waiter served the guests of one group, the infection risk decreased in the direction of the pathway in each group (Figure 2F and Figure S1F, respectively). In Pathway 7 (Figure 2G), the waiters served guests randomly, resulting in similar average infection risks at each table, except Table 2 (Figure 2H).