Human Vaccines & Immunotherapeutics (Jan 2023)

Safety and immunogenicity of SCB-2019, an adjuvanted, recombinant SARS-CoV-2 trimeric S-protein subunit COVID-19 vaccine in healthy 12–17 year-old adolescents

  • Pio Lopez,
  • Lulu Bravo,
  • Erik Buntinx,
  • Charissa Borja-Tabora,
  • Hector Velasquez,
  • Edith Johana Rodriquez,
  • Camilo A. Rodriguez,
  • Josefina Carlos,
  • May Emmeline B. Montellano,
  • Edison R. Alberto,
  • Milagros Salvani-Bautista,
  • Yung Huang,
  • Branda Hu,
  • Ping Li,
  • Htay Htay Han,
  • Carmen Baccarini,
  • Igor Smolenov

DOI
https://doi.org/10.1080/21645515.2023.2206359
Journal volume & issue
Vol. 19, no. 1

Abstract

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We previously demonstrated the efficacy of the COVID-19 vaccine candidate, SCB-2019, in adults in the SPECTRA phase 2/3 efficacy study. We extended the study to include 1278 healthy 12–17-year-old adolescents in Belgium, Colombia, and the Philippines who received either two doses of SCB-2019 or placebo 21 days apart, to assess immunogenicity as neutralizing antibodies against prototype SARS-CoV-2 and variants of concern, and safety and reactogenicity as solicited and unsolicited adverse events with a comparator group of young adults (18–25 years). In participants with no evidence of prior SARS-CoV-2 infection SCB-2019 immunogenicity in adolescents was non-inferior to that in young adults; respective geometric mean neutralizing titers (GMT) against prototype SARS-CoV-2 14 days after the second vaccination were 271 IU/mL (95% CI: 211–348) and 144 IU/mL (116–178). Most adolescents (1077, 84.3%) had serologic evidence of prior SAR-CoV-2 exposure at baseline; in these seropositive adolescents neutralizing GMTs increased from 173 IU/mL (135–122) to 982 IU/mL (881–1094) after the second dose. Neutralizing titers against Delta and Omicron BA SARS-CoV-2 variants were also increased, most notably in those with prior exposure. SCB-2019 vaccine was well tolerated with generally mild or moderate, transient solicited and unsolicited adverse events that were comparable in adolescent vaccine and placebo groups except for injection site pain – reported after 20% of SCB-2019 and 7.3% of placebo injections. SCB-2019 vaccine was highly immunogenic against SARS-CoV-2 prototype and variants in adolescents, especially in those with evidence of prior exposure, with comparable immunogenicity to young adults. Clinical trial registration: EudraCT 2020–004272–17; ClinicalTrials.gov NCT04672395.

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