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Volume 28, Number 2—February 2022
Research

Comparative Effectiveness of Coronavirus Vaccine in Preventing Breakthrough Infections among Vaccinated Persons Infected with Delta and Alpha Variants

Irina Kislaya1Comments to Author , Eduardo Freire Rodrigues1, Vítor Borges, João P. Gomes, Carlos Sousa, José P. Almeida, André Peralta-Santos, Baltazar Nunes, and PT-COVID-19 Group2
Author affiliations: Instituto Nacional de Saúde Doutor Ricardo Jorge, Lisbon, Portugal (I. Kislaya, V. Borges, J.P. Gomes, B. Nunes); Direção-Geral da Saúde, Lisbon (E.F. Rodrigues, A. Peralta-Santos); Unilabs, Porto, Portugal (C. Sousa, J.P. Almeida)

Main Article

Table 1

Characteristics of patients in the study sample, by severe acute respiratory syndrome coronavirus 2 variant of concern, Portugal, epidemiologic weeks 20–26 (May 17–July 4), 2021

Characteristic Delta (B.1.617.2), no. (%) Alpha (B.1.1.7), no. (%) Total, no. (%)
Overall
1,366 (100)
731 (100)
2,097 (100)
Week of diagnosis
20 53 (4) 137 (19) 190 (9)
21 64 (5) 154 (21) 218 (10)
22 112 (8) 171 (23) 283 (13)
23 192 (14) 114 (16) 306 (15)
24 249 (18) 73 (10) 322 (15)
25 350 (26) 38 (5) 388 (19)
26
346 (25)
44 (6)
390 (19)
Age group, y
40–49 760 (56) 378 (52) 1,138 (54)
50–69 474 (35) 313 (43) 787 (38)
>70
132 (10)
40 (5)
172 (8)
Sex
F 707 (52) 402 (55) 1,109 (53)
M 659 (48) 329 (45) 988 (47)

Main Article

1These first authors contributed equally to this article.

2Members of the PT-Covid-19 Group are listed at the end of this article.

Page created: November 29, 2021
Page updated: January 22, 2022
Page reviewed: January 22, 2022
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