Efficacy and Safety of Heterologous and Homologous COVID-19 Vaccination
Condition: Healthy Adult Volunteers
Study type: Interventional

Summary: 
      The investigators conduct a prospective analysis to compare homologous and heterologous
      adenovirus vector ChAdOx1-nCov-19 (Astra-Zeneca) or SARS-CoV-2 messenger RNA-1273 (Moderna)
      vaccine inoculation. Healthy volunteers will be enrolled and divided into five groups. The
      first group is the subjects who received ChAdOx1- nCov-19 vaccine with 8 weeks apart; the
      second group is the SARS-CoV-2 messenger RNA-1273 vaccine after the first dose of
      ChAdOx1-nCov-19 vaccination with 8 weeks apart; the third group is the first dose of
      ChAdOx1-nCov-19 vaccine and the SARS-CoV-2 messenger RNA-1273 vaccine with 4 weeks apart; the
      fourth group is the SARS-CoV-2 messenger RNA-1273 vaccination with 4 weeks apart; the fifth
      group is the first dose of ChAdOx1-nCov-19 vaccine and the SARS-CoV-2 messenger RNA-1273
      vaccine with 12 weeks apart. There will be 100 volunteers in each group. Antibody test on the
      day before and the 14th, 28th day and 12th week after the second dose of vaccination,
      including 100 subjects in each group for SARS-CoV-2 ELISA antibody titer and 50 people in
      each group for SARS-CoV-2 neutralizing antibody titer. Adverse reactions at the first day,
      the 14th day, the 28th day, and the 12th week. The research team follow up each volunteer at
      the 6th month.
    

Detailed description: 
      The investigators would like to conduct a prospective analysis to compare the same adenovirus
      vector ChAdOx1-nCov-19 (Astra-Zeneca) or SARS-CoV-2 messenger RNA-1273 (Moderna) vaccine
      inoculation and mixed inoculation of ChAdOx1-nCov-19 and messenger RNA-1273 vaccine. Healthy
      volunteers (including medical personnel) will be enrolled and divided into five groups
      according to their wishes. The five groups are: the first group is the subjects who received
      ChAdOx1- nCov-19 vaccine with 8 weeks apart; the second group is the SARS-CoV-2 messenger
      RNA-1273 vaccine after the first dose of ChAdOx1-nCov-19 vaccination with 8 weeks apart; the
      third group is the first dose of ChAdOx1-nCov-19 vaccine and the SARS-CoV-2 messenger
      RNA-1273 vaccine with 4 weeks apart; the fourth group is the SARS-CoV-2 messenger RNA-1273
      vaccination with 4 weeks apart; the fifth group is the first dose of ChAdOx1-nCov-19 vaccine
      and the SARS-CoV-2 messenger RNA-1273 vaccine with 12 weeks apart. There will be 100
      volunteers in each group, and blood will be drawn for antibody test on the day before and the
      14th, 28th day and 12th week after the second dose of vaccination, including 100 subjects in
      each group for SARS-CoV-2 ELISA antibody titer and 50 people in each group for SARS-CoV-2
      neutralizing antibody titer. This study analyzo the titers of SARS-CoV-2 antibodies, and
      records adverse reactions at each visits including the first day, the 14th day, the 28th day,
      and the 12th week (including those within 7 days after the inoculation). Adverse reactions
      and whether there is development of COVID-19 within 6 months will be recorded. The research
      team will also follow up by phone in the 6th month to ask whether there is vaccine associated
      adverse events or SARS-CoV-2 infection. The results will provide information for vaccine
      policy in Taiwan.
    

Intervention name(s): ChAdOx1-nCov-19 (Astra-Zeneca); SARS-CoV-2 messenger RNA-1273 (Moderna) vaccine
Intervention type(s): Biological; Biological
Intervention description(s): vaccine inoculation and mixed inoculation; vaccine inoculation and mixed inoculation
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: adenovirus-vector ChAdOx1 vaccination; messenger RNA (mRNA-1273 )vaccination; Coronavirus disease 2019 (COVID-19); humoral immunity; SARS-CoV-2; adverse events