Third COVID-19 vaccine dose assessed for people with weakened immune systems
A new study at University Hospital Southampton is investigating whether offering a third COVID-19 jab can offer greater protection for people with weakened immune systems.
The extension of the £2.2 million OCTAVE trial aims to recruit 1,200 patients across the UK. It opened in Southampton last month with the support of the NIHR Southampton Clinical Research Facility.
Results will be instrumental in informing how to best vaccinate people with weakened immune systems and protect them against COVID-19 infection.
Two doses not enough
People with weakened immune systems – referred to as immunocompromised – do not get as much protection from COVID-19 vaccination as others.
They might have a weaker immune system due to underlying health conditions or treatments for cancer, rheumatoid arthritis, inflammatory bowel disease, kidney disease or liver disease.
The OCTAVE trial has published preliminary data showing that 40% of people in these groups mounted a low, or undetectable, immune response after two doses.
The level of antibody response varied between the groups studied. T cell response, another key part of the immune protection, was similar to levels in healthy participants.
Do three doses give better protection?
The OCTAVE DUO research will engage up to 1,200 people already involved in the OCTAVE project or who have other at-risk conditions in parallel studies. They will include volunteers who had a low or absent immune response after two doses of vaccine (Oxford/AstraZeneca or Pfizer).
Participants will receive a third booster vaccine dose (of Pfizer, Moderna or Novavax). The researchers will then analyse their immune response to the vaccine, measure how long this response lasts, and use their healthcare records to see if they are later diagnosed with COVID-19.
The results will help predict which people could benefit most from a third vaccine dose and identify groups who still do not produce enough of an immune response to protect them.
"OCTAVE DUO is critical to helping us properly evaluate the benefit of the third vaccine dose in immunosuppressed patients,” explains Dr Sean Lim, who is leading the study.
“In doing so, it will also help highlight those who continue to be at risk from COVID-19, and may need benefit from alternative strategies beyond vaccination."
The ongoing study is co-funded by UK Research and Innovation (UKRI) and the government’s vaccine taskforce, and led by researchers at the University of Glasgow and University of Birmingham.