Intramuscular versus Subcutaneous COVID-19 needle length RCT

This study is a single blind, parallel group, 2-arm randomized controlled trial with 486 participants. The purpose of this study is to measure the immunogenicity and reactogenicity following Subcutaneous versus Intramuscular administration of the Pfizer Comirnaty COVID-19 booster vaccine in adults aged 18 - 75 years, who have previously received at least 2 doses of the COVID-19 vaccine and are eligible for the Pfizer Comirnaty COVID-19 booster vaccine, The study will be conducted within the New Zealand Pharmacy Research Network (PRN) and coordinated from the Medical Research Institute of New Zealand (MRINZ) research office located in the Wellington Regional Hospital. The primary outcome of this study is to assess the immunogenicity of Subcutaneous versus Intramuscular vaccine delivery, Participants will be recruited through social media platforms, pharmacies, GP and health clinics by staff members and investigators. They will be screened and enrolled remotely by study staff member from Medical Research Institute of New Zealand (MRINZ). Participants will be required to get blood drawn on three different occasions as well as attending a vaccination visit at a participating pharmacy/vaccination site in their area. They will need to complete online diaries from day 1 - day 7 after receiving the vaccine to record reactogenicity outcome. They will also have two additional surveys to complete on day 28 and 105. The primary outcome of this study is to assess the immunogenicity of Subcutaneous versus Intramuscular vaccine delivery,