A significant and consistent reduction in rotavirus gastroenteritis hospitalization of children under 5 years of age, following the introduction of universal rotavirus immunization in Israel

Figures & data

Table 1. Characteristics of children less than 5 years of age hospitalized for acute gastroenteritis, northern Israel 2007–2014

	N (total 6205)	Percent
Hospital
Carmel	1262	20.3
Hillel Yaffe	2406	38.8
Laniado	2537	40.9
Sex
Males	3336	53.8
Females	2837	45.7
Missing	32	0.5
Age
0–11 months	2478	39.9
12–23 months	2023	32.6
24–59 months	1638	26.4
Missing	66	1.1
Year
2007 (Nov-Dec)	313	5.0
2008	1223	19.7
2009	753	12.1
2010	1279	20.6
2011	697	11.2
2012	839	13.5
2013	810	13.1
2014 (Jan-July)	263	4.2
Missing	28	0.5
Rotavirus test
Tested	3514	56.6
Not-tested	2691	43.4
Rotavirus result
Positive	1137	32.4
Negative	2377	67.6

Figure 1. Weekly detection of rotavirus among hospitalized children with gastroenteritis, northern Israel, November 2007 – July 2014* * N = 6205 hospitalizations for acute gastroenteritis. Numbers of weekly rotavirus positive and negative samples were determined by weighted analysis.

Figure 2. Analysis of seasonality: number of weekly rotavirus gastroenteritis hospitalizations in children less than 5 years of age in (A) the period preceding universal rotavirus immunization (2008–2010), and (B) the period of universal vaccination period (2011–2013)* *Seasonality was analyzed using the observed weekly counts of RVGE cases in children less than 5 years of age. Each period included data for 3 years and 156 weeks.

Table 2. Estimated burden of hospitalizations due to all-cause AGE and RVGE among children aged 0–59 months in 2008–2013

Year/period	No. AGE hospitalizations	Population size*	Estimated annual incidence rate of AGE hospitalizations (per 1000, 95% CI)	No. rotavirus positive^†	Estimated annual incidence rate of RVGE hospitalizations (per 1000, 95% CI)	Estimated no. of AGE hospitalizations, Israel^‡	Estimated no. of RVGE hospitalizations Israel^‡
2008	1223	61990	19.7 (18.6–20.8)	377	6.1 (5.5–6.7)	14663	4520
2009	753	63565	11.8 (11.0–12.7)	187	2.9 (2.5–3.3)	8928	2217
2010	1279	65170	19.6 (18.5–20.7)	529	8.1 (7.4–8.8)	15184	6280
2011	697	66775	10.4 (9.6–11.2)	188	2.8 (2.4–3.2)	8300	2239
2012	839	67590	12.4 (11.6–13.3)	142	2.1 (1.8–2.5)	10119	1713
2013	810	68365	11.8 (11.0–12.6)	195	2.9 (2.5–3.3)	9874	2377
Annual average in the period preceding universal vaccination: 2008–2010	1085	63575	17.1 (16.1–18.1)	364	5.7 (5.1–6.3)	12917	4324
Annual average in the period of universal vaccination : 2011–2013	782	67552	11.6 (10.8–12.4)	175	2.6 (2.2–3.0)	9304	2110
Absolute reduction between the 2 periods (95% CI)	303	3977 growth	5.5 (4.2–6.8)	189	3.1 (2.4–3.8)	3613 (505 – 5884)**	2215 (1139 – 3353)**
Percent reduction between the 2 periods (95% CI)^§	28%	6.3% growth	32% (25%–40%)	52%	55% (43%–67%)	28% (5% – 40%)**	51% (39% – 59%)**

* Assuming that 80%, 25% and 65% of the pediatric populations of Hadera, Haifa and Hasharon sub-districts receive hospitalization services in Hillel Yaffe, Carmel and Laniado hospitals, respectively.

^† Estimated by weighted analysis using the inverse of sampling fraction with weights attributed separately to each age group (0–11, 12–23 and 24–59 months), each month and each year of hospitalization.

^‡ By extrapolating the regional incidence estimates to the entire Israeli pediatric population aged 0–59 months.

^§ Calculated as follows: [(Annual average in period 1 - annual average in period 2) / annual average in period 1]*100.

Where period 1 is the period preceding vaccination; and period 2 is the period of universal vaccination.

The 95% confidence intervals are presented in parenthesis.

** The 5^th and 95^th percentiles, produced by Montecarlo simulation with 100000 runs, are presented in parenthesis.

AGE: acute gastroenteritis, CI: confidence intervals, RVGE: rotavirus gastroenteritis.

Table 3. The change in the average annual rotavirus gastroenteritis hospitalization rate, from the period preceding universal vaccination (2008– 2010) to the period of universal vaccination (2011–2013), by age

Age (months)	No. AGE hospitalizations	Population size*	Estimated annual incidence rate of AGE hospitalizations (per 1000, 95% CI)	No. rotavirus positive†	Estimated annual incidence rate of RVGE hospitalizations (per 1000, 95% CI)	Estimated no. of AGE hospitalizations, Israel^‡	Estimated no. RVGE hospitalizations Israel^‡
0–11 months
Annual average: period preceding universal vaccination 2008–2010	428	12715	33.7 (30.1–37.0)	122	9.6 (8.0–11.4)	5098	1444
Annual average: period of universal vaccination 2011–2013	332	13510	24.6 (22.1–27.3)	51	3.8 (2.9–5.0)	3994	614
Absolute reduction between the 2 periods	97	795	9.1 (5.0–13.2)	71	5.8 (3.9–7.9)	1103 (230 – 2195)^**	830 (570–1108)^**
Percent reduction between the 2 periods^§	23%	6.3% growth	27% (15% – 39%)	58%	61% (40% – 82%)	22% (5% – 39%)^**	58% (52% – 61%)^**
12–23 months
Annual average pre universal vaccination period 2008–2010	363	12715	28.5 (25.8–32.0)	156	12.3 (10.5–14.3)	4329	1851
Annual average universal vaccination period 2011–2013	238	13510	17.6 (15.5–20.0)	66	4.9 (3.8–6.2)	2870	797
Absolute reduction between the pre and universal vaccination periods	125	795	10.9 (7.3–14.6)	90	7.4 (5.2–9.7)	1459 (−17 − 2275)^**	1053 (470 –1523)^**
Percent reduction between the pre and universal vaccination periods^§	35%	6.3% growth	38% (26% – 51%)	58%	60% (42% – 79%)	34% (0% – 45%)^**	57% (38% – 67%)^**
24–59 months
Annual average pre universal vaccination period 2008–2010	285	38145	7.5 (6.7–8.4)	83	2.2 (1.8–2.7)	3397	979
Annual average universal vaccination period 2011–2013	208	40531	5.1 (4.4–5.9)	56	1.4 (1.1–1.8)	2505	682
Absolute reduction between the pre and universal vaccination periods	77	2386 Growth	2.3 (1.2–3.5)	27	0.8 (0.2–1.0)	891 (−514 − 1694)^**	297 (−12 − 567)^**
Percent reduction between the pre and universal vaccination periods^§	27%	6.3% growth	31% (17%–82%)	32%	37% (9%–65%)	26% (−25% − 42%)^**	30% (−2% − 41%)

* The number of children aged 0–11 and 12–23 was estimated by division of the number of children aged 0–59 months by 5, this estimate was multiplied by 3 to reach the number of children aged 24–59 months.

^§ Calculated as follows: [(Annual average in period 1 - annual average in period 2) / annual average in period 1]*100.

Where period 1 is the period preceding vaccination; and period 2 is the period of universal vaccination.

In parenthesis presented are the 95 confidence intervals.

RV: rotavirus, AGE: acute gastroenteritis, CI: confidence intervals, RVGE: rotavirus gastroenteritis.

** In parenthesis presented are the 5^th and 95^th percentiles produced by Montecarlo simulation with 100000 runs.

^† Estimated by weighted analysis, using the inverse of sampling fraction with weights given separately for age group (0–11, 12–23 and 24–59 months) by months and year of hospitalization.

^‡ By extrapolating the regional incidence estimates to the entire Israeli pediatric population, according to the corresponding age group.

Figure 3. Appraisal of trends in the incidence of rotavirus gastroenteritis hospitalizations in children less than 5 years of age in the period preceding universal rotavirus immunization (2008–2010), and the period of universal vaccination (2011–2013)* * The black circles represent the incidence (per 1000) of rotavirus gastroenteritis hospitalizations in children less than 5 years; the red line represents the trend line, while the light blue line represents the smoothed curve.