Evaluating COVID-19 Vaccine Boosters: External Vaccines Trial Substudy (COV-BOOST EVT)

A randomised, phase II UK multi-centre study to determine reactogenicity and immunogenicity of booster vaccination against ancestral and novel variants of SARS-CoV-2

Status: Closed

Population: Adults (30 years and above)

Disease group: COVID-19

Funder: National Institute for Health Research (NIHR)

Sponsor: University Hospital Southampton NHS Foundation Trust 

Principal Investigator: Prof. Paul Heath

Study Aims

The COV-Boost study looks at the impact of different vaccines against COVID-19 when given as a booster vaccination. This study is trying to determine the side effect profile, safety, and immune response of giving a 3rd COVID-19 vaccine dose of BNT162b2 (Pfizer) to people who have previously received 2 doses of NVXCoV2373 (the Novavax vaccine). 

What does participating in the study involve?

The study lasts for 242 days (about 8 months) and involves 5 study visits with blood tests taken at each visit: 

  • Screening and vaccination visit: At the first visit, study staff talk to potential participants about the study and what to expect, and about their health and details of previous covid vaccines to check whether they can take part in the study.  If someone is eligible to take part and would like to do so, they are asked to sign a consent form.  
  • Participants then have vital signs checked and may have a physical examination by a doctor. They will have baseline antibody blood tests and tests of liver and kidney function for safety. Then, they receive the Pfizer vaccine as an injection into the arm. 
  • Follow-up after vaccination an “e-Diary”, thermometer and tape measure is given to participants to record their temperature and any symptoms they have for 7 days after they have the vaccine, and any symptoms for 21 days after the vaccine.  
  • Follow-up visits: participants return to the clinic for four short visits to check they are fine, any changes to their health or medicines and to have blood tests.  

For more information about the study, visit the study website here: https://www.covboost.org.uk/participate-substudy