Table 2

SARS-CoV-2 Secondary Attack Rates in Vaccinated and Unvaccinated Household Contacts during Replacement of Delta with Omicron Variant, Spain

Israel López-Muñoz, Ariadna Torrella, Olga Pérez-Quílez, Amaia Castillo-Zuza, Elisa Martró, Antoni E. Bordoy, Verónica Saludes, Ignacio Blanco, Laura Soldevila, Oriol Estrada, Lluís Valerio, Sílvia Roure, and Xavier Vallès

Author affiliations: North Metropolitan International Health Program, Catalan Institute of Health (PROSICS), Badalona, Spain (I. López-Muñoz, A. Torrella, O. Pérez-Quílez, A. Castillo-Zuza, L. Soldevila, L. Valerio, S. Roure, X. Vallès); Hospital Universitari Germans Trias i Pujol, Badalona (E. Martró, A.E. Bordoy, V. Saludes, I. Blanco, L. Soldevila, S. Roure); Center for Biomedical Research in Epidemiology and Public Health (CIBEREPS), Instituto de Salud Carlos III, Madrid, Spain (E. Martró, A.E. Bordoy, V. Saludes); Institut d’Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona (E. Martró, A.E. Bordoy, V. Saludes, I. Blanco, O. Estrada, X. Vallès); Fundació Lluita contra la Sida i les Malalties Transmissibles, Badalona (L. Soldevila, S. Roure, X. Vallès)

Main Article

Crude and adjusted risk factors for infection among contacts in the Omicron-dominant period in a study of SARS-CoV-2 secondary attack rates in vaccinated and unvaccinated household contacts during replacement of Delta with Omicron variant, Spain*

Variable	No. patients†	Crude OR		Adjusted OR‡
Variable	No. patients†	OR (95% CI)	p value	OR (95% CI)	p value
Vaccination status, contacts
Vaccinated	135/170	Referent		Referent
Unvaccinated	39/45	1.69 (0.7–4.3)	0.3	1.86 (0.6–6.2)	0.3
1 dose	25/29	Referent		Referent
2 doses	90/113	0.63 (0.2–2.0)	0.4	0.75 (0.2–2.9)	0.7
3 doses	19/27	0.38 (0.1–1.5)	0.2	0.36 (0.1–1.9)	0.2
Missing data	1/1
Time since vaccination, wk
1–13	36/48	Referent		Referent
14–20	28/35	1.33 (0.5–3.8)	0.6	2.17 (0.5–9.3)	0.3
21–25	34/41	1.62 (0.6–4.6)	0.4	2.41 (0.7–7.8)	0.1
>25	36/45	1.33 (0.5–3.6)	0.6	1.91 (0.6–5.7)	0.2
Missing data	1/1
Pooled		1.12 (0.8–1.5)	0.5	1.26 (0.9–1.8)	0.2
Age of contacts, y
0–12	36/42	Referent		Referent
13/18	22/27	0.73 (0.2–2.7)	0.6	0.99 (0.2–4.4)	0.9
19/35	38/47	0.70 (0.2–2.2)	0.5	0.94 (0.2–3.8)	0.9
36/45	33/42	0.61 (0.2–1.9)	0.4	0.83 (0.2–3.3)	0.8
>45	45/57	0.63 (0.2–1.8)	0.4	0.82 (0.2–3.2)	0.8
Pooled		0.90 (0.7–1.1)	0.4	0.94 (0.7–1.2)	0.6
Vaccination status, index patients
Vaccinated	134/161	Referent		Referent
Unvaccinated	40/54	0.56 (0.3–1.2)	0.1	0.98 (0.2–3.9)	0.9
Age of index patients, y
0–12	36/50	Referent		Referent
13–18	13/15	2.53 (0.5–12.7)	0.3	2.79 (0.4–20.4)	0.3
19–35	35/44	1.51 (0.6–3.9)	0.4	1.47 (0.4–5.8)	0.6
36–45	51/59	2.48 (0.9–6.5)	0.07	2.27 (0.5–10.5)	0.3
>45	39/47	1.90 (0.7–5.0)	0.2	1.84 (0.4–8.8)	0.4
Pooled		1.20 (0.9–1.5)	0.1	1.09 (0.8–1.5)	0.6
Number of housemates
<2	60/70	Referent		Referent
>2	114/145	0.61 (0.3–1.3)	0.2	0.62 (0.3–1.4)	0.3
Sex
M	93/115	Referent		Referent
F	81/100	1.13 (0.7–1.9)	0.6	0.97 (0.5–2.0)	0.9

*OR, odds ratio. †Values are number infected/total number of patients in each strata. ‡Adjusted analysis only included participants who had all data available.

Main Article

Page created: August 11, 2022

Page updated: September 20, 2022

Page reviewed: September 20, 2022

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