This is a quasi-experimental study with risk-based allocation. Public security and education professionals from the state government will be included. In the initial evaluation, the presence of comorbidities associated with an increased risk of serious disease due to COVID-19 will be evaluated, according to the national plan for the implementation of vaccination against COVID-19. Those with at least one of these comorbidities will be invited to receive the study vaccine in two doses, with an interval of 28 days (±7 days). Participants with low risk (without comorbidities as a risk factor for severe COVID-19 according to the national plan for the implementation of vaccination against COVID-19) will not receive the vaccine within the scope of the research project. If, after 12 months, the participant in the low-risk group (no vaccine) has not received CoronaVac, or any other vaccine available, he/she will receive the vaccine, exactly as offered in the other group (two doses of CoronaVac with an interval of 28 days - with a tolerance of 7 days before or after). All participants will be followed up for 12 months from inclusion in the study. Immunization is expected to reduce the risk of moderate to severe disease of those with comorbidities to the level of those of the same age group who do not have these comorbidities but face similar occupational risks.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
6,233
600 SU/dose; Two doses separated by 28 days (± 7 days). Intramuscular (deltoid) administration.
Escola Normal Superior - Universidade do Estado do Amazonas
Manaus, Amazonas, Brazil
Incidence density of moderate and severe clinical cases of COVID-19
Incidence density of moderate and severe clinical cases of COVID-19 (Grade 4 or higher according to the WHO clinical progression scale), after the second week after the second dose of the vaccine.
Time frame: 2 weeks after the second vaccine dose
Incidence density of moderate and severe clinical cases of COVID-19 after first dose
Incidence density of moderate and severe clinical cases of COVID-19 (grade 4 or higher according to the WHO clinical progression scale) from the first dose
Time frame: After first dose, up to 12 months.
Incidence density of moderate and severe clinical cases of COVID-19 after second dose
Incidence density of moderate and severe clinical cases of COVID-19 (grade 4 or higher according to the WHO clinical progression scale) from the second dose
Time frame: After second dose, up to 12 months.
Incidence density of severe clinical cases of COVID-19 after second dose
Incidence density of severe clinical cases of COVID-19 (grade 6 or higher according to the WHO clinical progression scale) from the second dose
Time frame: After second dose, up to 12 months.
Median of clinical progression scores between moderate and severe cases
Comparison of the median clinical progression scores according to the WHO clinical progression scale between groups
Time frame: After first dose, up to 12 months.
Incidence density of clinical cases virologically confirmed as COVID-19
Time frame: After first dose, up to 12 months.
Mortality confirmed as COVID-19
Incidence density of deaths confirmed as COVID-19
Time frame: After first dose, up to 12 months.
Incidence density of hospitalizations for any cause
Time frame: After first dose, up to 12 months.
Mortality from any cause
Density of mortality from any cause
Time frame: After first dose, up to 12 months.
Adverse events
Frequency of adverse events associated with the need for medical care
Time frame: Up to 7 days after each dose of the vaccine (Day 7 and Day 35)
Humoral and cell-mediated immune response
Quantification of humoral and cell-mediated immune response to vaccination in samples of a subgroup of participants
Time frame: Before each vaccine dose and every 3 months, up to 12 months of follow-up.
Detection of antibodies against SARS-CoV-2 in samples
Time frame: Before each vaccine dose and every 3 months, up to 12 months of follow-up
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