An observational study of breakthrough SARS-CoV-2 Delta variant infections among vaccinated healthcare workers in Vietnam.

Autor:	Chau NVV; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Ngoc NM; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Nguyet LA; Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam., Quang VM; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Ny NTH; Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam., Khoa DB; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Phong NT; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Toan LM; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Hong NTT; Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam., Tuyen NTK; Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam., Phat VV; Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam., Nhu LNT; Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam., Truc NHT; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., That BTT; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Thao HP; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Thao TNP; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Vuong VT; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Tam TTT; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Tai NT; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Bao HT; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Nhung HTK; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Minh NTN; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Tien NTM; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Huy NC; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Choisy M; Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK., Man DNH; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Ty DTB; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Anh NT; Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam., Uyen LTT; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Tu TNH; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Yen LM; Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam., Dung NT; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Hung LM; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Truong NT; Hospital for Tropical Diseaes, Ho Chi Minh City, Vietnam., Thanh TT; Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam., Thwaites G; Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK., Tan LV; Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.
Jazyk:	angličtina
Zdroj:	EClinicalMedicine [EClinicalMedicine] 2021 Nov; Vol. 41, pp. 101143. Date of Electronic Publication: 2021 Sep 30.
DOI:	10.1016/j.eclinm.2021.101143
Abstrakt:	Background: Data on breakthrough SARS-CoV-2 Delta variant infections in vaccinated individuals are limited. Methods: We studied breakthrough infections among Oxford-AstraZeneca vaccinated healthcare workers in an infectious diseases hospital in Vietnam. We collected demographic and clinical data alongside serial PCR testing, measurement of SARS-CoV-2 antibodies, and viral whole-genome sequencing. Findings: Between 11 th -25 th June 2021 (7-8 weeks after the second dose), 69 staff tested positive for SARS-CoV-2. 62 participated in the study. Most were asymptomatic or mildly symptomatic and all recovered. Twenty-two complete-genome sequences were obtained; all were Delta variant and were phylogenetically distinct from contemporary viruses obtained from the community or from hospital patients admitted prior to the outbreak. Viral loads inferred from Ct values were 251 times higher than in cases infected with the original strain in March/April 2020. Median time from diagnosis to negative PCR was 21 days (range 8-33). Neutralizing antibodies (expressed as percentage of inhibition) measured after the second vaccine dose, or at diagnosis, were lower in cases than in uninfected, fully vaccinated controls (median (IQR): 69.4 (50.7-89.1) vs. 91.3 (79.6-94.9), p=0.005 and 59.4 (32.5-73.1) vs. 91.1 (77.3-94.2), p=0.002). There was no correlation between vaccine-induced neutralizing antibody levels and peak viral loads or the development of symptoms. Interpretation: Breakthrough Delta variant infections following Oxford-AstraZeneca vaccination may cause asymptomatic or mild disease, but are associated with high viral loads, prolonged PCR positivity and low levels of vaccine-induced neutralizing antibodies. Epidemiological and sequence data suggested ongoing transmission had occurred between fully vaccinated individuals. Funding: Wellcome and NIH/NIAID. Competing Interests: All authors declare no competing interests. (© 2021 The Author(s).)
Databáze:	MEDLINE
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