Table 1.

First Week to Show an Increase Over Two Consecutive Previous Weeks and Peak Week for Key Surveillance Indicators of COVID-19, by COVID-19 Epidemic Wave, Japan, from Week 8, 2020 to Week 7, 2021 (as at February 28, 2021)^a.

	1) No. positive cases	2) No. tests	3) Test positivity	4) Average no. hospitalized cases	5) Average no. hospitalized severe cases	6) No. deaths
First wave
First week with increase over two consecutive weeks*	8	8	8	8	8	14
Peak week	15	20	8, 15	18	18	18**
Second wave
First week with increase over two consecutive weeks	25	24	25	27	30	31
Peak week	32	33	30, 31	33	34	35
Third wave
First week with increase over two consecutive weeks	41	43***	42	45	43	47
Peak week	1	3	53	3	3	5

^a the first week to show an increase over two consecutive previous weeks is when the indicator’s value for week X is greater than that for week X-1, and that for week X-1 is greater than that for week X-2. Surveillance indicators are 1) the number of SARS-CoV-2 positive cases; 2) the number of SARS-CoV-2 tests; 3) test positivity (number of SARS-CoV-2 positive cases divided by number of SARS-CoV-2 tests); 4) weekly average number of prevalent hospitalized COVID-19 cases; 5) weekly average number of prevalent hospitalized severe COVID-19 cases; and 6) number of COVID-19 deaths. All weeks are calendar weeks as defined by https://www.niid.go.jp/niid/ja/calendar.html.

*data available from week 6.

**excludes batch report in week 17 (https://www.mhlw.go.jp/stf/covid-19/open-data.html)

***excludes batch report in week 40 (https://www.mhlw.go.jp/stf/covid-19/open-data.html)