1.1 Prevalence of Respiratory Syncytial Virus
From 2014 to 2022, 4031 children were monitored by the sentinel hospitals. Among them, 216 positive cases were detected for RSV (5.36%). Of these, 126 patients were males (5.78%) and 90 were females (4.86%). The rate of RSV infection was significantly higher in males. The most positive cases were found in <3 years old, with 147 cases in this age group. The proportion of RSV-attributable decreased with age. In the age group of 12-14, there was only 1 positive case (0.42%). The rate of RSV infection varied significantly by age group.
Furthermore, the rate of RSV infection varied by different case categories, ranging from 2.67% in outpatient settings to 10.55% in inpatient settings. Detection of two genotypic subtypes varied significantly by age group. Among all RSV cases, the proportion of cases with a detection of RSV A is 89 (41.20%), while RSV B is 127 (58.80%). (Table 1)
Table 1 Baseline Information on the Detection of RSV in Children in Sentinel Hospitals in the Pudong New Area from 2014 to 2022
|
The number of monitoring
|
Positive number(%)
|
X2
|
P
|
Subtype A(%)
|
Subtype B(%)
|
X2
|
Gender
|
|
|
|
|
|
|
|
Male
|
2179
|
126(5.78)
|
1.681
|
0.195
|
55(43.65)
|
71(56.35)
|
0.525
|
Female
|
1852
|
90(4.86)
|
34(37.78)
|
56(62.22)
|
Age group
|
|
|
|
|
|
|
|
~3
|
1167
|
147(12.60)
|
176.758
|
<0.001
|
55(37.41)
|
92(62.58)
|
120.191
|
3~
|
915
|
36(3.93)
|
18(50.00)
|
18(50.00)
|
5~
|
958
|
19(1.98)
|
11(57.89)
|
8(42.10)
|
8~
|
754
|
13(1.72)
|
5(38.46)
|
8(61.54)
|
12~14
|
237
|
1(0.42)
|
0(0)
|
1(100.00)
|
Case category
|
|
|
|
|
|
|
|
Outpatient
|
2656
|
71(2.67)
|
110.712
|
<0.001
|
30(42.25)
|
41(57.75)
|
0.005
|
Inpatient
|
1375
|
145(10.55)
|
59(40.69)
|
86(59.31)
|
Total
|
4031
|
216(5.36)
|
|
|
89
|
127
|
|
1.2 Characteristics of Respiratory Syncytial Virus
Between 2014 and 2022, the surveillance population at the sentinel hospitals experienced an initial increase followed by a subsequent decrease. The sample size for pediatric cases ranged from 146 to 846, with the highest count observed in 2019 (846 cases). Additionally, the RSV positivity rate demonstrated an analogous trend, initially ascending before declining, reaching its pinnacle in 2016, and gradually diminishing thereafter. (Fig.1)
1.3 Result of HUAS
2.3.1 The detection of ARI incidence in various towns and communities in Pudong New Area.
The results of the HUAS show that the self-reported incidence of ARI varies among children in different towns and communities in Pudong New Area. Among them, the number of self-reported ARI cases is the highest in the Sanlin Town community, while it is the lowest in the Yangjing Street community in Pudong New Area. (Fig.2)
2.3.2 Information on self-reported incidence of ARI
3225 children were surveyed in 46 survey points, including 1674 boys (51.9%) and 1551 girls (48.1%). The average age of the participants was 6.36 years (IQR=4.49-9.50). The age group of 5~ years old has the highest number of patients, with 1326 for a rate of 41.12 per 100; whereas the age group of 3 ~Years old has the lowest number, with only 331 patients for a rate of 10.26 per 100.
Among all children, 1088 children self-reported having symptoms of acute respiratory tract infection in the past three months. The attack rate is 33.74% which 5~The most common age group is 49.85%, followed by the second group in the group of children 3~ years old, the incidence rate of <3 years old group is not significantly different from that of children aged 12-16 years old. (Table 2)
Table 2 The self-reported Acute Respiratory Infection (ARI) incidence rate among children in Pudong New Area communities.
Population characteristics
|
Survey number
|
Number of self-reported ARI cases
|
ARI attack rate(%)
|
Respondent
|
|
|
|
Parents
|
2754
|
999
|
36.27
|
(Material)Grandparent
|
142
|
20
|
14.08
|
Other family members
|
138
|
16
|
11.59
|
Non-relative
|
191
|
53
|
27.75
|
Gender
|
|
|
|
Male
|
1674
|
556
|
33.21
|
Female
|
1551
|
532
|
34.30
|
Age Group
|
|
|
|
<3
|
479
|
78
|
16.28
|
3~
|
331
|
108
|
32.63
|
5~
|
1326
|
661
|
49.85
|
8~
|
584
|
156
|
26.71
|
12-14
|
505
|
85
|
16.83
|
Total
|
3225
|
1088
|
33.74
|
1.4 Estimating the burden of disease with RSV
2.4.1Medical visit behavior of community children with ARI
Among 1088 children who self-reported experiencing ARI symptoms in the past three months, 399 children (36.67%) sought treatment at a hospital. (Table 3)
Table 3 Medical visit behavior on community children with ARI at HUAS
Population characteristics
|
Number of self-reported ARI cases
|
Number of visits
|
The ARI-related clinic visit rate
|
Gender
|
Male
|
556
|
195
|
35.07%
|
Female
|
532
|
204
|
38.35%
|
Age Group
|
<3
|
78
|
31
|
39.74%
|
3~
|
106
|
48
|
45.28%
|
5~
|
663
|
243
|
36.65%
|
8~
|
155
|
56
|
36.13%
|
12-14
|
86
|
21
|
24.42%
|
Total
|
|
1088
|
399
|
36.67%
|
2.4.2 Coverage of community members in sentinel hospitals
In 3225 subjects, 1956 participants indicated that they would choose one of the five hospitals for medical care when experiencing ARI symptoms. Among the five hospitals, the Children's Medical Center has the highest coverage rate at 42.23%, while Yangsi Hospital has the lowest rate at 1.12%. (Table 4)
Table 4 Emergency department coverage rate of children with Acute ARI at surveillance hospitals in Pudong New Area.
Age
|
Dongfang hospital(%)
|
Pudong hospital(%)
|
Yangsi hospital(%)
|
Zhoupu hospital(%)
|
Children's Medical Center(%)
|
Total(%)
|
<3(N=479)
|
6.89
|
8.77
|
1.25
|
2.51
|
39.25
|
58.66
|
3~(N=331)
|
3.93
|
5.44
|
0.00
|
5.44
|
53.78
|
68.58
|
5~(N=1326)
|
0.05
|
2.41
|
1.66
|
1.96
|
45.02
|
56.03
|
8~(N=584)
|
5.48
|
5.31
|
0.68
|
3.94
|
41.27
|
56.68
|
12-16(N=505)
|
0.10
|
9.70
|
0.79
|
5.74
|
31.29
|
57.43
|
Total(N=3225)
|
6.02
|
5.33
|
1.12
|
3.35
|
42.23
|
60.65
|
2.4.3 Estimating the burden of disease associated with children's RSV
According to estimates, from 2014 to 2022, the number of RSV-infected children in the outpatient and emergency departments in Pudong New Area is 4,285,000. The annual number of patients of RSV-infected children in the outpatient and emergency departments is as follows: 940,000, 1,090,000, 423,000, 731,000, 671,000, 35,000, 57,000, 20,000, 317,000. The rate of RSV-infected children in outpatient and emergency care is 6.58%, with annual rates of 13.01%, 15.39%, 5.92%, 10.28%, 9.34%, 0.48%, 0.78%, 0.27%, and 4.23%.
From 2014 to 2022, the number of RSV-infected children in the community in Pudong New Area is 11,685,000. The annual breakdown of RSV-infected children in the community is as follows: 2,564,000, 2,974,000, 1,154,000, 1,994,000, 1,830,000, 95,000, 155,000, 54,000, and 866,000. The rate of RSV-infected children in the community is 17.95%, with annual rates of 35.49%, 41.96%, 16.13%, 28.02%, 25.47%, 1.31%, 2.14%, 0.74%, 11.54%.
From 2014 to 2022, the rate of RSV-infected children in outpatient, emergency care, and the community peaked in 2015 at 10.90% and 41.96%, respectively. The rate remained high in 2017. (Table 5 and Fig.3)
In addition, detection of the number and the rate of RSV-infected children in outpatient, emergency care, and the community varied significantly by different seasons. During the winter season, the number of cases and the rate of RSV-infected children in outpatient, emergency care, and the community are at their lowest. In 2019, the rate of RSV-infected children in outpatient and emergency care reached the lowest point(0.02%), the rate of RSV-infected children in the community was 0.06%. Except for the peak incidence in the spring of 2019, the peak incidence in the other eight years occurred in the autumn(Fig.4).
Table 5 The estimated burden of children's RSV disease from 2014 to 2022
Time
|
The number of acute respiratory infection (ARI) cases in sentinel hospital emergency departments
|
RSV positivity rate
|
Coverage rate of hospital monitoring
|
The number of RSV cases in outpatient emergency department(10000)
|
population(10000)
|
the rate of RSV-infected children in outpatient, emergency care(95%CI)
|
Community ARI case visit rate
|
The number of RSV cases in the community
(10000)
|
the rate of RSV-infected children in the community(%)
|
2014
|
1018672
|
5.36%
|
58.08%
|
9.40
|
72.2358
|
13.01(12.94,13.09)
|
36.67%
|
25.64
|
35.49(35.38,35.60)
|
2015
|
1181606
|
5.36%
|
58.08%
|
10.90
|
70.8656
|
15.39(15.30,15.47)
|
36.67%
|
29.74
|
41.96(41.85,42.08)
|
2016
|
458375
|
5.36%
|
58.08%
|
4.23
|
71.513
|
5.92(5.86,5.97)
|
36.67%
|
11.54
|
16.13(16.05,16.22)
|
2017
|
792470
|
5.36%
|
58.08%
|
7.31
|
71.1737
|
10.28(10.20,10.35)
|
36.67%
|
19.94
|
28.02(27.92,28.23)
|
2018
|
727263
|
5.36%
|
58.08%
|
6.71
|
71.8692
|
9.34(9.27,9.40)
|
36.67%
|
18.30
|
25.47(25.37,25.57)
|
2019
|
37591
|
5.36%
|
58.08%
|
0.35
|
72.1526
|
0.48(0.47,0.50)
|
36.67%
|
0.95
|
1.31(1.29,1.34)
|
2020
|
61414
|
5.36%
|
58.08%
|
0.57
|
72.371
|
0.78(0.76,0.80)
|
36.67%
|
1.55
|
2.13(2.10,2.17)
|
2021
|
21587
|
5.36%
|
58.08%
|
0.20
|
73.8595
|
0.27(0.26,0.28)
|
36.67%
|
0.54
|
0.74(0.72,0.76)
|
2022
|
343917
|
5.36%
|
58.08%
|
3.17
|
74.9801
|
4.23(4.19,4.28)
|
36.67%
|
8.66
|
11.54(11.47,11.61)
|
Total
|
4642895
|
5.36%
|
58.08%
|
42.85
|
651.0205
|
6.58(6.56,6.60)
|
36.67%
|
116.85
|
17.95(17.92,17.98)
|