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.

Methods

Study Design

We conducted a retrospective longitudinal cohort study using 2 MOH national repositories: the COVID-19 vaccine repository and the SARS-CoV-2 test repository. The national COVID-19 vaccine repository includes vaccine type, vaccine lot number, and date of dose administration for each person vaccinated in Israel. The national SARS-CoV-2 PCR test database includes the results of each test performed, the date of testing, and the date results were obtained for each person. It also includes the date of hospitalization, severity of illness, and date of death of persons with COVID-19, if applicable. Personal identifiers such as unique personal identity number, age, and sex of each person registered in the repositories (because of PCR testing or vaccination) are included in both databases. We retrieved individual deidentified data from both databases and matched persons by using twice-encrypted unique personal identity numbers.

During the first stage of our study, we determined VE for booster dose vaccine recipients against SARS-CoV-2 infection by using unvaccinated persons as controls. During the second stage, we determined the rate reduction for hospitalizations, severe or critical disease, and deaths among persons who tested positive for SARS-CoV-2 after the booster dose (i.e., breakthrough cases).

We defined as index dates the dates on which third-dose vaccine recipients in our study received the booster dose (Figure 1, panel A).

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.