A single-blind, randomised, phase II multi-centre study to determine reactogenicity and immunogenicity of heterologous prime/boost COVID-19 vaccine schedules in adolescents (COMCOV-3)  

Status: Closed to recruitment 

Population: Paediatric  

Disease Group: COVID-19

Funder: UK Vaccine Task Force (VTF), National Institute Health Research (NIHR), Coalition for Vaccine Preparedness Innovations (CEPI), Novavax (Vaccine supply) 

Sponsor: University of Oxford 

Principal Investigator: Professor Paul Heath 

Study Aims

The purpose of this part of the study is to find out how well young people (aged 12-15½ years) respond to a third dose of COVID-19 vaccine. We will compare the side effects and immune response to different options for the third dose, including two “low dose” options. 

What does participating in the study involve?

In this part of study, we will recruit a total of about nationally 380 participants. All will have already received two standard doses of Pfizer vaccine. We will arrange to see them about 3 months after their second vaccination for the first study visit. At this visit, participants will be randomly allocated to one of five groups to determine which study vaccine they will receive: 

1.    Adult dose Pfizer vaccine, given at the first study visit
2.    Low dose Pfizer vaccine, given as one-third dose adult vaccine at the first study visit
3.    Low dose Pfizer vaccine, given as full dose paediatric vaccine at the first study visit
4.    Adult dose Novavax vaccine, given at the first study visit
5.    Two doses of the Group B meningitis vaccine (given at the first and third study visits); then adult a dose of the Pfizer bivalent vaccine, given at the fourth study visit (around 6 months after the first visit) 

Participants will have a blood test at each visit, to measure immunity to COVID-19. Anaesthetic cream can be provided to minimise discomfort from the blood tests. 

Participants will complete a diary to record symptoms experienced after vaccination. 

Lateral flow tests will be required at the first visit and then weekly for four weeks. All participants will also be asked to take a lateral flow test if they have symptoms of COVID-19 (such as fever, cough, sore throat or loss of smell or taste) at any time during the study. Participants in Group 5 will also have a lateral flow test before their fourth visit vaccination and then weekly for four weeks afterwards. 

There will be 4 or 5 Visits over a 6- or 7-month period, Visits will take place at St George’s University of London Hospital. 

Contact Email: com-cov3@sgul.ac.uk 

Study Website: Participate – St George’s University of London Hospital | Com-CoV (comcovstudy.org.uk)