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Study to Describe the Safety, Tolerability, Immunogenicity, and Potential Efficacy of RNA Vaccine Candidates Against COVID-19 in Healthy Adults

Our take —

This vaccine trial will test multiple versions of an RNA-based vaccine against SARS-CoV-2 across different age groups with different vaccination regimens. In addition to incidence of COVID-19 in study participants, antibody titer will be assessed over a period of two-years, allowing response and longevity of response to be analyzed. Though assessing multiple vaccine candidates and multiple vaccine regimens at one time may make interpretation of the data and therefore selection of a lead candidate difficult, a successful trial of this nature could greatly speed the time to identification of a viable candidate vaccine.

Study design

This is a multi-arm, placebo-controlled and observer-blinded phase 1/2 study of four different RNA-based vaccine candidates against SARS-CoV-2. The intention is to determine the correct dose for each of the vaccine candidates, and identify the best candidate based on safety, tolerability, immunogenicity, and potential efficacy. The four different RNA-based vaccine candidates will be tested at multiple doses (low, medium, and high) across multiple age ranges (18-55, 65-85, and 18-85 years) with either one or two dose regimens, for a total of 18 study groups with 3 placebo groups (age 18-55, age 65-85, and age 18-85 years) receiving a single injection. This study will be performed in three stages: Stage 1 will identify the preferred vaccine candidate, dose level and dosing regimen; Stage 2 will be an expanded cohort study presumably to examine immunogenicity, and Stage 3 will be a final large-scale study with the final candidate, dose, and regimen most likely to examine efficacy.

Study population and setting

7600 participants will be recruited consisting of  healthy males and females age 18-85 years with no previous clinical or microbiological diagnosis of COVID-19. Participants must be HIV, hepatitis C, and hepatitis B-negative, have no known medical or psychiatric condition, and have no known history of severe adverse reaction or severe allergies associated with a vaccine. Additionally, participants must not have received medications intended to treat COVID-19, must not be immunocompromised, have not received treatment with immunosuppressive therapy; have no history of autoimmune disorder; have no condition associated with prolonged bleeding; not be pregnant or breast-feeding; as well as others. Stage 1 participants must not work in occupations with high risk of exposure to SARS-CoV-2, must not test positive on serological tests for SARS-CoV-2, have no abnormal hematology and/or blood chemistry laboratory values, and must have a SARS-CoV-2 NAAT-negative nasal swab within 24 hours of the vaccine administration.

Recruitment centers are at the University of Maryland General Clinical Research Center, the University of Maryland Medical Center Investigational Drug Service Pharmacy, the University of Maryland, Center for Vaccine Development and Global Health, and NYU Langone Health.

Primary outcome measures will include injection site reactions, adverse and serious events, , and hematology and chemistry laboratory values and changes. Secondary outcomes include analysis of SARS-CoV-2 serum neutralizing antibodies, and serum antibodies specific to SARS-CoV-2 spike protein and the receptor binding domain of the spike protein. Analysis will occur at multiple time points over two years and will include antibody titer, change in titer over time, percent of participants who achieve greater than or equal to a four-fold increase in antibody titer. Confirmed COVID-19 incidence will also be monitored.

Summary of Main Findings

N/A, study is incomplete

Study Strengths

N/A, study is incomplete


N/A, study is incomplete

Value added

Assessing multiple vaccine candidates and multiple vaccine regiment at one time could greatly speed the time to identification of a viable candidate vaccine. Testing antibody titers over two years will aid in understanding the longevity of the immune response to the vaccine. If successful, this has the potential to be the first licensed RNA-based vaccine.