Outbreak of occupational Brucella infection caused by live attenuated Brucella vaccine in a biological products company in Chongqing, China, 2020

Figures & data

Table 1. Infection rate across different demographics in the outbreak of occupational Brucella infection occurred in the biological products company, Chongqing, China, 2020.

Variables	Total	No. of cases	Infection rate (%)	χ^2	p
Gender
Male	73	30	41.10	0.38	0.54
Female	67	31	46.27
Age (years)
20—29	27	18	66.67	7.63	0.05
30—39	57	22	38.60
40—49	40	16	40.00
50—59	16	5	31.25
Length of service (years)
<1	14	5	35.71	1.82	0.61
1–2	24	13	54.17
3–4	49	22	44.90
≥5	53	21	39.62
Posts classification
Vaccine production	73	41	56.16	–	0.02*
Laboratory quality control	10	4	40.00
Experimental preparation	11	4	36.36
Logistician	42	12	28.57
Animal caretaker	4	0	0
Work place
Vaccine production workshop	71	39	54.93	–	0.007**
Vaccine sub-packaging workshop	65	22	33.85
Animal laboratory	4	0	0
Building
A	21	8	38.10	-	<0.0001**
B	29	4	13.79
C	77	43	55.84
D	4	0	0
E	9	6	66.67

Note: – Fisher’s exact test. *p < 0.05, **p < 0.01.

Figure 1. Spatial distribution of employees in the outbreak of occupational Brucella infection occurred in the biological products company, Chongqing, China, 2020.

Table 2. Infection risk among different workplaces in the outbreak of occupational Brucella infection occurred in the biological products company, Chongqing, China, 2020.

Possible exposure place	Cases	Controls	OR
Animal laboratory (Ref)	0	4	1.00
Vaccine sub-packaging workshop	22	43	+∞
Vaccine production workshop	39	32	+∞

Figure 2. The employees in the vaccine production workshop of the company detected positive for Brucella through occupational health examinations, 2015–2020.

Table 3. Crude odds ratios for statistically significant association between Brucella infection and working places in the biological products company, Chongqing, China, 2020.

Working place	Exposures		%		OR (95%CI)
	cases (n = 61)	Controls (n = 79)	Cases	Controls
Vaccine production workshop	39	32	63.93	40.51	2.60 (1.31–5.19)
Vaccine sub-packaging workshop	22	43	36.07	54.43	0.47 (0.24–0.94)

Figure 3. The main production process of live attenuated Brucella vaccine in the biological products company, Chongqing, China.