To evaluate the efficacy and safety of vaccinating children and adolescents, aged 3 to 17 years, with a two-dose schedule of the inactivated vaccine (Coronavac) against SARS-Cov-2.
Nine hundred sixty (960) participants will be randomized into 2 groups, in a 2:1 ratio, to receive the inactivated Coronavac/Butantan vaccine (VACC, N=640) and a group to receive the immunizing BNT162b2 (Pfizer) (BNTC, N=320). The VACC group will also be compared to a group of adults aged 18 to 49 who received Coronavac (ADU, N=160). The main outcome will be the geometric title of neutralizing antibodies and the secondary outcomes will be the incidence of the number of cases confirmed by RT-PCR, the cellular immune response and frequency of adverse events. Outcomes will be evaluated before the first dose, and 28 and 90 days after the second dose, and followup after 6 and 12 months. The study hypothesis is that the cellular and humoral immune response of children and adolescents is not inferior to the age group 18 to 49 years, who received Coronavac and compared to children vaccinated with the immunizing BNT162b2 (Pfizer) and that the inactivated vaccine presents lower reactogenicity for the age group studied.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
QUADRUPLE
Enrollment
1,120
Inactivated Coronavac/Butantan vaccine in 2 doses of 0.5 ml, 4 weeks apart
BNT162b2 (Pfizer) vaccine in 2 doses of 0.1 ml or 0.30 ml (according to age group), 4 weeks apart
Valéria Valim
Vitória, Espírito Santo, Brazil
RECRUITINGViral neutralization assay
Neutralizing antibody titers will be expressed by the ability of antibodies to neutralize up to 50% the number of plaques (PRNT50). Title \> 1:50 will be considered positive.
Time frame: 3 months
Chemiluminescence serological assay for qualitative and quantitative determination of neutralizing antibodies against Spike protein (anti-SARS-Cov-2 anti-IgG-S)
Results are expressed in AU/mL and data interpretation will be as follows: \<50 AU/mL = negative; ≥50 U/mL = positive.
Time frame: 3 months
Serological assay by chemiluminescence for qualitative and quantitative determination of specific IgG antibodies against the nucleocapsid protein of SARS-Cov-2
Results will be expressed as fluorescence intensity or pg/mL. The cutoff is 1.4 and \<1.4 = negative; ≥1.4 = positive.
Time frame: 3 months
Dosage of systemic soluble factors
Chemokines, cytokines and growth factors - biomarkers of humoral and cellular response. Results will be expressed in pg/mL.
Time frame: 12 months
Antigen-specific stimulation of peripheral blood mononuclear cells in vitro
The results will be expressed as a positive percentage frequency for a given cell phenotype.
Time frame: 2 months
T lymphocytes
The results will be expressed as a positive percentage frequency for a given cell phenotype.
Time frame: 12 months
B lymphocytes
The results will be expressed as a positive percentage frequency for a given cell phenotype.
Time frame: 12 months
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intracytoplasmic cytokines
The results will be expressed as a positive percentage frequency for a given cell phenotype.
Time frame: 12 months
RT-PCR confirmed cases
Cases confirmed by RT-PCR, whose signs/symptoms have started 15 days after the second dose of vaccine, over 6 months after receiving the vaccine.
Time frame: 6 months
Adverse events
Surveillance of adverse post-vaccine events (PVAE) and adverse events of special interest (EAIE) will be carried out.
Time frame: 6 months