Table 4.

Characteristics of emerging space-time clusters of COVID-19 cases at machi-level in Nagasaki Prefecture from 2020/4/1 to 2021/6/30

Cluster	Period	Duration (Days)	Radius (km)	Observed Cases	Expected Cases	RR	P-value	Machi (Total)	Machi (RR > 1)	Population
1	2020/12/9–2021/6/30	203	2.39	433	73.83	6.6	< 0.001	98	82	68,358
2	2021/1/3–2021/6/30	178	3.37	260	63.75	4.34	< 0.001	37	28	67,268
3	2021/3/31–2021/6/30	91	0	36	0.34	106.89	< 0.001	1	1	699
4	2020/12/21–2021/6/30	191	1.88	237	67.96	3.68	< 0.001	40	27	66,876
5	2021/4/23–2021/6/30	68	8.61	113	24.36	4.77	< 0.001	46	28	66,672
6	2020/12/19–2021/6/30	193	14.01	187	68.46	2.84	< 0.001	89	37	66,654
7	2021/4/16–2021/6/30	75	0	23	0.4	57.78	< 0.001	1	1	996
8	2021/5/28–2021/6/30	33	23.79	71	12.17	5.94	< 0.001	89	28	67,622
9	2021/4/26–2021/6/30	65	4.34	90	23.79	3.86	< 0.001	29	14	68,094
10	2020/12/20–2021/6/30	192	1.47	28	1.79	15.74	< 0.001	6	5	1755
11	2020/12/28–2021/6/30	184	7.16	65	15.06	4.38	< 0.001	55	23	15,377
12	2021/4/14–2021/6/30	77	0	9	0.037	242.81	< 0.001	1	1	90
13	2020/12/10–2021/6/30	202	4.78	147	72.92	2.06	< 0.001	20	10	67,843
14	2021/4/19–2021/6/30	72	2.09	47	13.87	3.42	< 0.001	20	8	35,891
15	2021/1/12–2021/6/30	169	0	8	0.23	34.8	< 0.001	1	1	256
16	2021/1/14–2021/6/30	167	1.83	11	1.19	9.27	< 0.05	3	2	1338
17	2021/1/13–2021/6/30	168	3.06	19	4.01	4.76	< 0.05	4	3	4479
18	2021/4/26–2021/6/30	177	0	10	0.94	10.65	< 0.05	1	1	2694
19	2021/5/1–2021/6/30	176	1.85	16	3.13	5.13	< 0.05	7	4	9700