Covid-19 Vaccination in Adolescents

  • End date
    Mar 31, 2025
  • participants needed
  • sponsor
    The University of Hong Kong
Updated on 22 July 2021


Objectives To assess the reactogenicity, measure the adaptive immune responses and track the long-term immune memory in 11-years-old or above adolescents and adults such as their parents receiving the COVID-19 vaccines-BNT162b2, CoronaVac-chosen by the Hong Kong Government; to compare the reactogenicity and immunogenicity across the vaccines used for these children and their respective parents, and between the children and their parents.

Hypothesis to be tested The safety profile and the magnitude and durability of immune responses to the COVID-19 vaccines in young adolescents are non-inferior to those in middle-aged adults.

Design and subjects A single-site, comparative nonrandomised clinical trial for 300 healthy individuals or patients between 11-17 years old and one or both healthy parents and unrelated adults to receive one of COVID-19 vaccines.

Instruments Mobile app for subjects to record adverse effects, enzyme-linked immunosorbent assay, plaque reduction neutralization assay, luciferase immunoprecipitation system assay and flow cytometry.

Interventions BNT162b2 and CoronaVac.

Main outcome measures Types and frequencies of adverse effects within 7 days, and changes and peaks of antibody levels and antigen-specific memory T cell responses for 3 years.

Data analysis Comparison of rates of each type of adverse effects, immune responses at each timepoint across the vaccines and age groups by ANOVA and multivariate longitudinal statistical models, decay of immune response modelled by regression analysis.

Condition COVID19
Treatment CoronaVac, Tozinameran, Oxford-AstraZeneca COVID-19 vaccine
Clinical Study IdentifierNCT04800133
SponsorThe University of Hong Kong
Last Modified on22 July 2021


Yes No Not Sure

Inclusion Criteria

informed consent from the parents or a legally acceptable representative for an underage participant
for students, aged 11 years or above
biological parents of students enrolled in the trial or unrelated healthy adults
ability to adhere to the follow-up schedules
willingness to report reactogenicity daily for 7 days post dose 1 and 2 (and 3) proactively
willingness to receive that vaccine available for that particular recruitment period (as student-parent pair, if applicable)
good past health, including pre-existing clinically stable disease, such as paediatric or immune disorders
prior COVID-19 (for COVID-19 survivor subgroup)

Exclusion Criteria

reported pregnancy or breastfeeding
history of severe neurological conditions, e.g. transverse myelitis, Guillain-Barre Syndrome (GBS), demyelinating diseases
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