Study design and participants
syphilis, allergy, infections, HIV, hepatitis
SYPHILIS, ALLERGY, INFECTIONS
Considering the lower weight of adolescents and generally higher immune responses compared to adults, we used two different doses of 1/10 (1x10Before the start of the clinical trial, a pre-screening stage was added to ensure the rapid enrollment of the planned quantity of participants. Volunteers (not yet participants) signed informed voluntary consent to medical examination and underwent the same medical procedures (free of cost) at pre-screening stage as it was planned at screening (double-check examination). To minimize the likelihood of volunteers becoming seropositive, the individuals who passed the pre-screening step were invited immediately to the screening (in groups of 10–20) without waiting for the pre-screening stage to be completed. De facto, the average time between the pre-screening stage and vaccination with the first dose for each individual was 7 days. The study (including pre-screening and screening stages) was carried out in two centers in Russia: Morozov Children’s City Clinical Hospital of the Moscow City Health Department and Children’s City Clinical Hospital named after Z. A. Bashlyaeva of the Moscow City Health Department.The study was launched on June 5, 2021 (screening of the first volunteer) and involved healthy volunteers of both sexes aged from 12 to 17 years. Screening procedure included physical examination assessing relevant vital functions (e.g., blood pressure, ECG, pulse oximetry and axillar temperature) as well as collection of demographic and anthropometric data. Volunteers underwent also laboratory testing: complete blood count and serum biochemistry, testing for infections (HIV, hepatitis, and syphilis), coagulation, COVID-19 diagnostics (PCR, IgM/IgG ELISA) and urine testing for drugs, alcohol, and pregnancy (in women). Healthy volunteers with no history of COVID-19 or prior contact with patients with COVID-19 within 14 days of participation in the study, did not receive any other vaccinations within 30 days, had not undergone therapy with steroids, immunoglobulins, or any other blood-derived products within 30 days, had not consumed any immunosuppressive drugs for more than 3 months and had no allergy to immunobiological preparations including any vaccine component were considered eligible. A complete list of inclusion and exclusion criteria is given in the The trial was registered at 