Table 3.

Characteristics of emerging space-time clusters of COVID-19 cases at machi-level in Nagasaki Prefecture from 2020/4/1 to 2021/3/31

Cluster	Period	Duration (Days)	Radius (km)	Observed Cases	Expected Cases	RR	P-value	Machi (Total)	Machi (RR > 1)	Population
1	2020/12/9–2021/3/31	112	2.38	216	26.37	9.22	< 0.001	107	72	67,548
2	2021/1/3–2021/3/31	87	3.49	137	20.4	7.21	< 0.001	30	21	67,107
3	2020/12/21–2021/3/31	100	1.8	112	23.72	4.96	< 0.001	39	24	67,998
4	2020/12/13–2021/3/31	108	15.03	93	17.46	5.57	< 0.001	80	28	46,378
5	2020/12/28–2021/3/31	93	8.14	51	7.2	7.27	< 0.001	68	21	22,161
6	2020/12/20–2021/3/31	101	1.47	21	0.62	34.37	< 0.001	6	5	1755
7	2020/12/10–2021/3/31	111	6.36	92	25.6	3.74	< 0.001	43	20	66,175
8	2020/12/10–2021/3/31	111	4.68	86	25.42	3.51	< 0.001	31	14	65,704
9	2020/12/10–2021/3/31	111	4.78	76	25.37	3.09	< 0.001	35	16	65,587
10	2020/12/24–2021/3/31	97	2.84	65	19.61	3.41	< 0.001	75	27	57,924
11	2021/1/6–2021/3/31	84	11.36	31	4.64	6.78	< 0.001	38	8	15,812
12	2021/1/13–2021/3/31	77	5.72	18	1.21	15.06	< 0.001	4	3	4479
13	2020/12/19–2021/3/31	102	6.47	26	4.2	6.27	< 0.001	9	3	11,805
14	2020/12/10–2021/3/31	111	3.78	46	12.91	3.63	< 0.001	16	8	33,375
15	2020/12/28–2021/3/31	93	11.28	56	21.72	2.63	< 0.001	76	16	66,898