A randomised controlled trial of the immunogenicity and reactogenicity of subcutaneous vs intramuscular administration of COVID-19 vaccination in community pharmacies in Aotearoa New Zealand

The current vaccination guidelines provide non-specific advice for needle length selection, and only 2% of COVID-19 vaccine doses in Aotearoa New Zealand (A/NZ) are actually administered with a needle longer than 25 mm.  

mat napo 1moqJf2GVpo unsplash
Principal Investigator
Medical Research Institute of New Zealand
Public Contact
Nicola Marshall - MRINZ Communication and Outreach Advisor
Project Timeframe/Status
In Process

Whakarāpopoto Rangahau Summary of Research

COVID-19 mRNA vaccines are registered for intramuscular (IM) injection, however the standard 25mm needle length is insufficient to ensure deltoid muscle delivery in up to 45% of adults with obesity. The current vaccination guidelines provide non-specific advice for needle length selection, and only 2% of COVID-19 vaccine doses in Aotearoa New Zealand (A/NZ) are actually administered with a needle longer 25 mm.  

It is currently unknown whether regulatory-mandated IM delivery of COVID-19 vaccines is essential to achieve full therapeutic effects and whether inadvertent subcutaneous (SC) delivery could lead to increased reactogenicity and local adverse events following vaccination. 

This study is a randomised controlled trial of 486 adults conducted at community pharmacies across A/NZ. Study participants will be randomised to receive a booster dose of Pfizer bi-valent COVID-19 vaccine by IM or SC injection. This study will compare immunogenicity and reactogenicity following vaccination by IM or SC route. 

read more

Te Hiranga ā Rangahau Research Impact

If differences between reactogenicity and immunogenicity are identified between SC and IM delivery of vaccination, these findings would directly influence public health practice in A/NZ and globally. Vaccination guidelines which ensure IM delivery could reduce side effects following vaccination, potentially reducing vaccine hesitancy and in turn reducing the burden of disease that disproportionately affects Māori, Pacific, and other disadvantaged groups.

As concern regarding adverse events following immunisations is known to result in vaccine hesitancy and refusal, highlighted during A/NZ Immunisation Programme, therefore identifying differences in reactogenicity will have direct relevance to vaccine uptake. If results show that SC and IM administration gives comparable immunogenicity, this provides reassurance for clinicians and for people with obesity, who may have previously received inadvertent “off-label” SC delivery, that they are likely to be adequately protected.  

This project will validate the capacity in A/NZ to undertake embedded research within community pharmacy vaccination clinics and will would further develop pharmacist research capacity. This will ensure the network of embedded community pharmacy research hubs across A/NZ are able to rapidly and efficiently respond when a new infectious disease threat emerges.

read more

Te Niwha

Kairangahau Research Personnel

Project Leaders 

Dr Gabby Shortt
Medical Research Institute of New Zealand 

Professor Richard Beasley
Medical Research Institute of New Zealand 

Research Team

Ms Melemafi Porter
MRINZ | Study Coordinator/Pacific Advisor

Mr Simon Phillips, Ngā Rauru, Ngāti Ruanui, Atiawa, Ngāti Whatua
Maraeroa Marae Health Clinic | Trial Steering Committee  

Adj. Professor Alex Semprini
MRINZ | Senior Oversight 

Professor Mark Weatherall
University of Otago  | Statistician 

Mrs Trisha Falleni, Ngāti Kuia, Ngāti Koata, Ngāti Apa Ki te Rā Tō
MRINZ | Māori Health Research Advisor

Dr Tom Hills
Middlemore Hospital | Senior Oversight

Mr Nick Shortt
MRINZ | Database Development / Informatics Management 

Mrs Kyley Kerse
MRINZ | Pharmacy Manager 

Ms Bianca Black
MRINZ | Study Monitor 

Ms Tanira Kingi, Ngāti Toa Rangatira, Te Arawa (Ngāti Whakaaue)
University of Otago, MRINZ | Summer Student 

read more

Project Timeframe 

​2 years 


Aotearoa New Zealand Community Pharmacy Research Network 

Media Contact 

Nicola Marshall
MRINZ Communication and Outreach Advisor 
Phone: 021 256 4737