Table 3.

Weighted and adjusted regional SARS-CoV-2 antibody positivity in unvaccinated primary school children and by COVID-19 vaccination status in secondary school children during Round 1 (10 November–10 December 2021) in the SIS2 study.

	Primary		Secondary
	Total		Total		Vaccinated		Unvaccinated
Region	n*	Antibody positive† (% (95CIs))	n*	Antibody positive† (% (95CIs))	n*	Antibody positive† (% (95CIs))	n*	Antibody positive† (% (95CIs))
East Midlands	225	39.5 (30.1–49.5)	161	72.4 (62.3–81.1)	110	92.7 (78.7–98.7)	51	65.1 (52–76.8)
East of England	382	50.3 (40.6–59.9)	181	82.1 (73.8–88.7)	101	100 (94.3–100)	80	66.4 (53.7–77.5)
London	366	34.8 (27.9–42.1)	145	88.7 (78.1–95.3)	66	100.0 (96.8 – 100.0)	79	79.1 (59.8–92)
North East	383	46.5 (40.7–52.4)	354	75.1 (69.3–80.3)	195	92.9 (86.7–96.8)	159	59.9 (51–68.3)
North West	418	49.3 (43.7–54.8)	248	87.5 (81.7–91.9)	126	98.1 (92.9–99.8)	122	79.3 (69.4–87.2)
South East	297	30.2 (22.6–38.8)	239	79.7 (72.6–85.6)	122	96.8 (90.3–99.4)	117	59.9 (48.2–70.8)
South West	254	21.9 (13.9–31.8)	453	70.2 (64.7–75.3)	262	97.3 (93–99.3)	191	56.0 (48.2–63.5)
West Midlands	134	53.8 (43.1–64.3)	67	88.3 (70.4–97.3)	28	100 (81–100)	39	78.6 (46.1–96.3)
Yorkshire and the Humber	247	39.1 (31.7–46.8)	426	89.0 (83.6–93.1)	261	94.7 (86.4–98.7)	165	87.8 (80.9–92.9)
Total	2706		2274		1003		1271

^*n denotes the number of samples tested.

^†Weighted by age, sex, ethnicity and sampling design.