Table 2.

Pertussis incidence by age group in Yiwu, Zhejiang province, from 1 June 2021 to 31 May 2022.

Age Group	Eip, n	Eop, n	Mcs, %	Epc, n	Resident Population, N	Ip (95% CrI a)
<1 y	29.6	84.8	100.0	114.4	13,738	832.7 (614.9–1059.4)
1 y	0.0	149.5	90.0	166.2	19,872	836.4 (434.0–1308.8)
2–3 y	3.5	187.7	82.7	231.2	36,722	629.6 (385.7–925.7)
4–5 y	5.9	353.3	86.4	415.7	36,013	1154.3 (817.4–1553.5)
6–19 y	3.7	492.1	45.0	1101.9	220,586	499.5 (331.2–828.6)
20–59 y	0.0	94.5	62.8	150.5	1,341,805	11.2 (6.3–17.7)
≥60 y	1.4	14.0	73.3	21.0	190,654	11.0 (0.8–32.6)
All groups	46.5	1463.4	75.0	2013.2	1,859,390	108.3 (91.7–126.4)

^a Calculated by the bootstrap method, the calculation involved the 95% CrI of hospitalization coverage preference rates of SHs, the 95% CrI of the positive rate of enrolled outpatient suspected pertussis cases, the 95% CrI of the medical consultation coverage preference rates of SHs, and the 95% CrI of the medical consultation rates of survey-identified suspected pertussis cases (all shown in the online resources). Eip, estimated inpatient pertussis cases in all hospitals of Yiwu, calculated with Formula (4) in Section 2.4; Eop, estimated outpatient pertussis cases in all hospitals of Yiwu, calculated with Formulas (5) and (6) in Section 2.4; Mcs, medical consultation rate of survey-identified suspected pertussis cases, calculated with Formula (3) in Section 2.2; Epc, estimated pertussis cases in community of Yiwu, calculated with Formula (7) in Section 2.5; Ip, pertussis incidence per 100,000 person-years, calculated with Formula (8) in Section 2.5; CrI, confidence interval; n, the number of Eip/Eop/Epc; N, the number of resident population; y, year.