Clinical trial NCT05059106: EFFECTIVENESS, SAFETY AND IMMUNOGENICITY OF THE HALF DOSE OF THE VACCINE ChadOx1 nCoV-19 (AZD1222) for COVID-19
Official title: EFFECTIVENESS, SAFETY AND IMMUNOGENICITY OF THE HALF DOSE OF THE VACCINE ChadOx1 nCoV-19 (AZD1222) for COVID-19
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: PHASE2
PHASE3
Conditions: SARS-CoV-2
Keywords: vaccines
immunity
covid-19
Lead sponsor: Federal University of Espirito Santo
Sponsor class: OTHER
Collaborators: name: Centro de Pesquisas René Rachou
name: Escola Nacional de Saúde Pública Sérgio Arouca/Fiocruz
name: Oswaldo Cruz Foundation
name: Escola Superior de Ciências da Santa Casa de Misericórdia de Vitória
First posted: 2021-09-28
Enrollment: 29637
Sex: ALL
Minimum age (years): 18
Maximum age (years): 49
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NON_RANDOMIZED
Intervention model: SEQUENTIAL
Primary purpose: PREVENTION

Brief summary: This study is clinical trial (intervention study with external comparison group) to test vaccination with reduced dose (half dose) of ChAdOx1 nCoV-19 (AZD1222), in a 2-dose schedule with an interval of 8 weeks, including all adults aged 18 to 49 years from Viana city - Espírito Santo (ES)/Brazil, on the incidence of new cases over 12 months following treatment, compared to an external group from same state and adjusted for socio-demographic and epidemiological variables.

Detailed description: This study is clinical trial (intervention study with external comparison group) to test vaccination with reduced dose (half dose) of ChAdOx1 nCoV-19 (AZD1222), in a 2-dose schedule with an interval of 8 weeks, including all adults aged 18 to 49 years from Viana city - Espírito Santo (ES)/Brazil, on the incidence of new cases over 12 months following treatment, compared to an external group from same state and adjusted for socio-demographic and epidemiological variables. Cellular and humoral immunity will be studied in a representative sub-sample compared to an external reference group (cohort of health workers) vaccinated with standard dose. The outcomes will be evaluated at 28 days after the second dose and follow-up after 6 months and 12 months. The main outcome will be to decrease in 60% the incidence of new cases over 6 months after receiving the vaccine. The clinical epidemiological variables will be obtained from e-SUS VS, e-SUS notifica and datasus: number of cases, number of deaths with specific ICD for covid-19, number of hospital admissions for covid-19; number of ICU admissions for the treatment of SARS, total number of tests (RT-PCR) performed and positive. The cellular and humoral immune response will be assessed by viral neutralization assay (neutralizing antibody test), serological assay by chemiluminescence, determination of specific IgM and IgG profiles, measurement of systemic soluble factors (chemokines, cytokines and growth factors), stimulation antigen-specific peripheral blood mononuclear cells in vitro and investigation of memory T and B lymphocytes and intracytoplasmic cytokines. It is estimated to include 29,637 people in the study, to reach 85% vaccination cover of individuals aged 18-49 years. The subsample size immunogenicity test is 600 individuals from the eligible population, estimating losses of 15% and study power of 90%, alpha error of 1%. The hypothesis of the study is that the reduction in the incidence of covid-19 and the cellular and humoral immune response achieved with a half dose will be similar to the reduction expected with the standard dose.

Eligibility criteria: Inclusion Criteria:

- residents of Viana, Espírito Santo, aged between 18 and 49 years

Exclusion Criteria:

* Pregnant women;
* History of severe allergic reaction (anaphylaxis) to any previously administered vaccine;
* Having received another vaccine in the last 14 days;
* Belonging to a priority risk group for vaccination, as per the PNI recommendations;
* Have fever or flu-like symptoms;
* Have previously received any vaccine for covid-19 at any time;
* Recent diagnosis of covid-19 with onset of symptoms 28 days before vaccination;
* Disorders of coagulation and use of anticoagulants.

Primary outcomes:
measure: Incidence of new cases
timeFrame: 12 months
Secondary outcomes:
measure: Number of deaths
timeFrame: 12 months
measure: number of hospital admissions
timeFrame: 12 months
measure: number of intensive care unit (ICU) admissions
timeFrame: 12 months
measure: number of tests (RT-PCR)
timeFrame: 12 months
measure: Viral Neutralization Assay
timeFrame: 4 and 8 months
measure: serological assay
timeFrame: 8 and 10 months
measure: IgM
timeFrame: 8 and 10 months
measure: IgG
timeFrame: 8 and 10 months
measure: systemic soluble factors
timeFrame: 8 and 10 months
measure: Antigen-specific stimulation of peripheral blood mononuclear cells
timeFrame: 10 and 12 months
measure: Lymphocyte investigation
timeFrame: 10 and 12 months
measure: Cytokine investigation
timeFrame: 10 and 12 months
Other outcomes:
measure: Adverse events
timeFrame: 14 months
Locations:
city: Vitória
country: Brazil
facility: Federal University of Espirito Santo
state: Espirito Santo
Study officials:
References: