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Vaccine effectiveness against transmission of alpha, delta and omicron SARS-COV-2-infection, Belgian contact tracing, 2021-2022.
Braeye, Toon; Catteau, Lucy; Brondeel, Ruben; van Loenhout, Joris A F; Proesmans, Kristiaan; Cornelissen, Laura; Van Oyen, Herman; Stouten, Veerle; Hubin, Pierre; Billuart, Matthieu; Djiena, Achille; Mahieu, Romain; Hammami, Naima; Van Cauteren, Dieter; Wyndham-Thomas, Chloé.
  • Braeye T; Department of Epidemiology and public health, Sciensano, Juliette Wytsmansstraat 14, 1000 Brussel, Belgium. Electronic address: toon.braeye@sciensano.be.
  • Catteau L; Department of Epidemiology and public health, Sciensano, Juliette Wytsmansstraat 14, 1000 Brussel, Belgium.
  • Brondeel R; Department of Epidemiology and public health, Sciensano, Juliette Wytsmansstraat 14, 1000 Brussel, Belgium.
  • van Loenhout JAF; Department of Epidemiology and public health, Sciensano, Juliette Wytsmansstraat 14, 1000 Brussel, Belgium.
  • Proesmans K; Department of Epidemiology and public health, Sciensano, Juliette Wytsmansstraat 14, 1000 Brussel, Belgium.
  • Cornelissen L; Department of Epidemiology and public health, Sciensano, Juliette Wytsmansstraat 14, 1000 Brussel, Belgium.
  • Van Oyen H; Department of Epidemiology and public health, Sciensano, Juliette Wytsmansstraat 14, 1000 Brussel, Belgium; Department of Public Health and Primary Care, Ghent University, Corneel Heymanslaan 10, 9000 Gent, Belgium.
  • Stouten V; Department of Epidemiology and public health, Sciensano, Juliette Wytsmansstraat 14, 1000 Brussel, Belgium.
  • Hubin P; Department of Epidemiology and public health, Sciensano, Juliette Wytsmansstraat 14, 1000 Brussel, Belgium.
  • Billuart M; Department of Epidemiology and public health, Sciensano, Juliette Wytsmansstraat 14, 1000 Brussel, Belgium.
  • Djiena A; Agence pour une Vie de Qualité, Rue de la Rivelaine 11, 6061 Charleroi, Belgium.
  • Mahieu R; Common Community Commission Brussels, Rue Belliard 71/1, 1040 Brussels, Belgium.
  • Hammami N; Agency for Care and Health, Infection Prevention and Control, Flemish Community, Koningin Maria Hendrikaplein 70 bus 55, 9000 Gent, Belgium.
  • Van Cauteren D; Department of Epidemiology and public health, Sciensano, Juliette Wytsmansstraat 14, 1000 Brussel, Belgium.
  • Wyndham-Thomas C; Department of Epidemiology and public health, Sciensano, Juliette Wytsmansstraat 14, 1000 Brussel, Belgium.
Vaccine ; 41(20): 3292-3300, 2023 05 11.
Article in English | MEDLINE | ID: covidwho-2292542
ABSTRACT

OBJECTIVES:

Vaccine effectiveness against transmission (VET) of SARS-CoV-2-infection can be estimated from secondary attack rates observed during contact tracing. We estimated VET, the vaccine-effect on infectiousness of the index case and susceptibility of the high-risk exposure contact (HREC).

METHODS:

We fitted RT-PCR-test results from HREC to immunity status (vaccine schedule, prior infection, time since last immunity-conferring event), age, sex, calendar week of sampling, household, background positivity rate and dominant VOC using a multilevel Bayesian regression-model. We included Belgian data collected between January 2021 and January 2022.

RESULTS:

For primary BNT162b2-vaccination we estimated initial VET at 96% (95%CI 95-97) against Alpha, 87% (95%CI 84-88) against Delta and 31% (95%CI 25-37) against Omicron. Initial VET of booster-vaccination (mRNA primary and booster-vaccination) was 87% (95%CI 86-89) against Delta and 68% (95%CI 65-70) against Omicron. The VET-estimate against Delta and Omicron decreased to 71% (95%CI 64-78) and 55% (95%CI 46-62) respectively, 150-200 days after booster-vaccination. Hybrid immunity, defined as vaccination and documented prior infection, was associated with durable and higher or comparable (by number of antigen exposures) protection against transmission.

CONCLUSIONS:

While we observed VOC-specific immune-escape, especially by Omicron, and waning over time since immunization, vaccination remained associated with a reduced risk of SARS-CoV-2-transmission.
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Full text: Available Collection: International databases Database: MEDLINE Main subject: COVID-19 Type of study: Experimental Studies / Observational study / Prognostic study Topics: Vaccines / Variants Limits: Humans Country/Region as subject: Europa Language: English Journal: Vaccine Year: 2023 Document Type: Article

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Full text: Available Collection: International databases Database: MEDLINE Main subject: COVID-19 Type of study: Experimental Studies / Observational study / Prognostic study Topics: Vaccines / Variants Limits: Humans Country/Region as subject: Europa Language: English Journal: Vaccine Year: 2023 Document Type: Article