Effectiveness of BNT162b2 Vaccine Booster Against SARS-CoV-2 Infection and Breakthrough Complications, Israel

Aharona Glatman-Freedman; Michal Bromberg; Yael Hershkovitz; Hanna Sefty; Zalman Kaufman; Rita Dichtiar; Lital Keinan-Boker

Disclosures

Emerging Infectious Diseases. 2022;28(5):948-956.

Abstract and Introduction

Abstract

We estimated vaccine effectiveness (VE) of the BNT162b2 (Pfizer-BioNTech, https://www.pfizer.com) booster dose against SARS-CoV-2 infection and reduction of complications (hospitalization, severe disease, and death) among breakthrough cases in persons in Israel ≥16 years of age for ≤20 weeks. VE estimates reached 96.8% (95% CI 96.0%–97.5%) for persons 16–59 years of age and 93.1% (95% CI 91.8%–94.2%) for persons ≥60 years of age on week 3. VE estimates remained at these levels for 8 weeks in the 16–59 age group and 11 weeks in those ≥60. A slow decline followed, becoming more pronounced in the last 2–3 weeks of evaluation. Estimates in the last week of evaluation were 77.6% (95% CI 68.4%–84.2%) and 61.3% (52.5%–68.4%) for persons 16–59 years and ≥60 years, respectively. The more pronounced VE decline coincided with rapid increase in Omicron variant activity. Rate reduction of breakthrough complications remained moderate to high throughout the evaluation.

Introduction

The mass severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) BNT162b2 (Pfizer-BioNTech, https://www.pfizer.com) vaccination campaign in Israel was associated with a decline in the number of SARS-CoV-2 infections, hospitalizations, and deaths, reaching a nadir by mid-May 2021.^[1] However, beginning the third week of June 2021, a new rise in the number of SARS-CoV-2 cases was observed, including cases among fully vaccinated persons.^[1,2] Waning humoral immune response after the second vaccine dose was then found to be associated with increased incidence of SARS-CoV-2–related infections, hospitalizations, and deaths caused primarily by the B.1.617.2 (Delta) variant.^[3] In response to the increasing illness and deaths, the Israel Ministry of Health (MOH) recommended a third (booster) BNT162b2 vaccine dose for persons for whom at least 5 months had passed after receiving the second vaccine dose.^[4] The elderly and other high-risk groups were prioritized at first,^[4] and other age groups were added rapidly thereafter.^[5] We estimated the booster dose vaccine effectiveness (VE) against SARS-CoV-2 infection and the rate reduction of complications in breakthrough coronavirus disease (COVID-19) cases after the BNT162b2 booster dose in persons ≥16 years of age, by age group, for up to 20 weeks after receipt of the booster dose.

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Next Section

Abstract and Introduction
Methods
Results
Discussion
References

Table 1. Rate reduction of hospitalizations among SARS-CoV-2–positive persons who received the BNT162b2 COVID-19 vaccine booster dose, Israel*
Age group, y	Time of first positive SARS-CoV-2 PCR test after index date, wk	Unvaccinated SARS-CoV-2–positive persons		Vaccinated SARS-CoV-2–positive persons		Adjusted 1 – IRR, % (95% CI)†
Age group, y		Hospitalized	Total	Hospitalized	Total	Adjusted 1 – IRR, % (95% CI)†
16–59	2	889	22,545	4	1,343	92.2 (77.9–97.3)
	3	770	18,232	3	455	83.9 (46.7–95.1)
	4	590	12,962	2	293	84.6 (47.1–95.5)
	5	414	8,555	1	210	90.1 (44.5–98.2)
	6	259	5,531	1	138	84.3 (15.1–97.1)
	7	175	3,573	0	131	100.0
	8	120	2,626	1	83	74.0 (−52.5 to 95.6)
	9	92	2,013	0	54	100.0
	10	72	1,714	0	57	100.0
	11	69	1,401	0	66	100.0
	12	68	1,385	0	90	100.0
	13	72	1,442	0	118	100.0
	14	62	1,569	1	154	84.4 (5.9–97.4)
	15	64	2,145	4	351	62.8 (−0.6 to 86.2)
	16	71	4,088	1	884	94.0 (47.9–99.3)
	2–16 combined	1,662	41,135	18	4,427	89.2 (79.1–94.4)
>60	2	644	1,985	98	1,314	77.5 (71.5–82.3)
	3	666	2,200	39	464	73.0 (64.4–79.5)
	4	647	2,160	36	375	68.2 (52.7–78.6)
	5	619	2,164	25	319	73.2 (48.2–86.2)
	6	593	2,033	20	296	77.3 (62.5–86.3)
	7	501	1,724	29	271	64.5 (50.2–74.7)
	8	375	1,276	23	221	65.3 (40.2–79.9)
	9	254	869	6	147	86.7 (72.6–93.6)
	10	163	577	10	86	64.1 (27.1–82.3)
	11	108	376	9	63	54.9 (−35.9 to 85.1)
	12	80	258	4	44	71.0 (21.5–89.3)
	13	56	208	3	52	80.2 (54.4–91.4)
	14	56	183	3	49	81.9 (45.8–94.0)
	15	58	170	6	47	67.5 (32.6–84.4)
	16	53	162	5	44	65.7 (23.4–84.6)
	17	46	151	1	56	94.4 (57.3–99.2)
	18	42	147	1	69	95.0 (72.1–99.1)
	19	38	184	5	125	82.6 (57.7–92.8)
	20	46	305	13	432	81.4 (67.0–89.5)
	2–20 combined	1,976	6,673	336	4,474	75.1 (71.3–78.5)

*COVID-19, coronavirus disease; IRR, incidence rate ratio; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.
†Adjusted for sex and epidemiologic week.

Table 2. Rate reduction of severe or critical disease among SARS-CoV-2–positive persons who received the BNT162b2 COVID-19 vaccine booster dose, Israel*
Age group, y	Time of first positive SARS-CoV-2 PCR test after index date, wk	Unvaccinated SARS-CoV-2–positive persons		Vaccinated SARS-CoV-2–positive persons		Adjusted 1 – IRR, % (95% CI)†
Age group, y		Severe or critical disease	Total	Severe or critical disease	Total	Adjusted 1 – IRR, % (95% CI)†
16–59	2	422	22,545	2	1,343	92.0 (70.0–97.9)
	3	358	18,232	0	455	100.0
	4	262	12,962	0	293	100.0
	5	170	8,555	0	210	100.0
	6	113	5,531	0	138	100.0
	7	63	3,573	0	131	100.0
	8	40	2,626	0	83	100.0
	9	32	2,013	0	54	100.0
	10	27	1,714	0	57	100.0
	11	29	1,401	0	66	100.0
	12	24	1,385	0	90	100.0
	13	25	1,442	0	118	100.0
	14	21	1,569	0	154	100.0
	15	30	2,145	0	351	100.0
	16	30	4,088	0	884	100.0
	2–16 combined	727	41,135	2	4,427	97.3 (89.7–99.3)
≥60	2	450	1,985	56	1,314	81.9 (75.4–86.7)
	3	470	2,200	27	464	73.5 (61.0–82.0)
	4	464	2,160	18	375	77.8 (63.1–86.8)
	5	469	2,164	15	319	78.9 (66.8–86.6)
	6	447	2,033	9	296	86.6 (74.2–93.0)
	7	390	1,724	12	271	81.4 (63.1–90.6)
	8	299	1,276	13	221	75.6 (54.1–87.0)
	9	207	869	2	147	94.6 (85.3–98.0)
	10	128	577	9	86	58.6 (11.1–80.7)
	11	78	376	2	63	86.2 (39.1–96.9)
	12	52	258	3	44	69.0 (−15.3 to 91.7)
	13	40	208	1	52	91.0 (63.8–97.8)
	14	42	183	2	49	84.0 (44.8–95.3)
	15	45	170	3	47	78.5 (49.3–90.8)
	16	37	162	3	44	70.3 (30.0–87.4)
	17	32	151	1	56	91.7 (43.4–98.8)
	18	28	147	0	69	100.0
	19	33	184	4	125	83.6 (47.0–94.9)
	20	42	305	7	432	89.0 (75.8–95.0)
	2–20 combined	1,465	6,673	187	4,474	81.6 (78.3–84.3)

*COVID-19, coronavirus disease; IRR, incidence rate ratio; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.
†Adjusted for sex and epidemiologic week.

Table 3. Rate reduction of deaths among SARS-CoV-2–positive persons who received the BNT162b2 COVID-19 vaccine booster dose, Israel*
Age group, y	Time of first positive SARS-CoV-2 PCR test after index date, wk	Unvaccinated SARS-CoV-2–positive persons		Vaccinated SARS-CoV-2–positive persons		Adjusted 1 – IRR, % (95% CI)†
Age group, y		Deaths	Total	Deaths	Total	Adjusted 1 – IRR, % (95% CI)†
16–59	2	45	22,545	0	1,343	100
	3	36	18,232	0	455	100
	4	27	12,962	0	293	100
	5	17	8,555	0	210	100
	6	11	5,531	0	138	100
	7	6	3,573	0	131	100
	8	5	2,626	0	83	100
	9	4	2,013	0	54	100
	10	3	1,714	0	57	100
	11	3	1,401	0	66	100
	12	3	1,385	0	90	100
	13	2	1,442	0	118	100
	14	1	1,569	0	154	100
	15	1	2,145	0	351	100
	16	1	4,088	0	884	100
	2–16 combined	72	41,135	0	4,427	100
≥60	2	243	1,985	31	1,314	81.9 (70.4–88.9)
	3	246	2,200	13	464	76.0 (55.3–87.2)
	4	226	2,160	13	375	68.1 (49.6–79.8)
	5	229	2,164	11	319	68.7 (42.7–82.9)
	6	201	2,033	7	296	76.5 (55.9–87.4)
	7	166	1,724	8	271	70.5 (29.4–87.7)
	8	122	1,276	8	221	63.1 (29.4–80.7)
	9	89	869	2	147	87.6 (53.7–96.7)
	10	59	577	5	86	49.1 (−44.3 to 82.1)
	11	30	376	0	63	100.0
	12	19	258	1	44	67.7 (−189.8 to 96.4)
	13	19	208	1	52	78.7 (−89.9 to 97.6)
	14	22	183	1	49	85.0 (8.5–97.5)
	15	21	170	1	47	85.3 (−21.3 to 98.2)
	16	17	162	0	44	100.0
	17	11	151	1	56	74.6 (−225.9 to 98.0)
	18	10	147	0	69	100.0
	19	7	184	2	125	56.5 (−144.3 to 92.3)
	20	8	305	3	432	70.7 (−2.7 to 91.7)
	2–20 combined	686	6,673	108	4,474	77.1 (71.2–81.8)

*COVID-19, coronavirus disease; IRR, incidence rate ratio; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.
†Adjusted for sex and epidemiologic week.