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New study in North West London to test third COVID-19 vaccine for people with weakened immune systems

  • New clinical trial to investigate whether a third dose of COVID-19 vaccine for people with weakened immune systems, including those with cancer, gives a stronger immune response than two doses.
  • Participants will be given either Pfizer, Moderna or Novavax as a third dose of vaccine.
  • The government-funded study follows the results of the OCTAVE trial showing that 89% of people who are immunocompromised or immunosuppressed generate antibodies, and 60% generate a strong antibody response after two doses.

A new clinical trial to determine whether a third dose of vaccine will improve the immune response for people who have weakened immune systems is launching in the UK.

The study, OCTAVE DUO, will offer people who are immunosuppressed or immunocompromised a Pfizer, Moderna or Novavax vaccine to determine whether this will give a stronger immune response than two doses.

It is opening locally in North West London at Hammersmith Hospital, part of Imperial College Healthcare NHS Trust.

The £2.2 million study will build on the OCTAVE trial, led by the University of Glasgow and co-ordinated by the University of Birmingham’s Cancer Research UK Clinical Trials Unit.

The OCTAVE trial has published preliminary data in The Lancet showing that 89% of people who are immunocompromised or immunosuppressed generate antibodies following vaccination, and 60% generated a strong antibody response following two doses of a vaccine.

However, 40% of people in these groups mounted a low, or undetectable, immune response after two doses, and the level of antibody response varies between the groups studied.

The level of antibodies required for protection from COVID-19 is still not known, and it is likely that T cells also play an important role in protecting people from the virus. These findings therefore don’t provide a conclusive assessment of the protection vaccines offer people with weakened immune systems.

Up to 1,200 patients who are already involved in the OCTAVE study or those with other at-risk conditions involved in parallel studies will be recruited to the OCTAVE DUO trial.

The OCTAVE DUO study, co-funded by the government’s Vaccines Taskforce and UK Research and Innovation (UKRI) and led by the University of Glasgow and University of Birmingham, will analyse in detail the immune response of this group to the vaccine and the durability of this protection. It will also use healthcare records to determine whether any participants are later diagnosed with COVID-19.

Initial results are expected later this year to inform the UK’s COVID-19 vaccine deployment in these specific at-risk groups. The trial will follow the patients to mid-2022 and offer more detailed information at that stage about the immune responses that develop in these groups.

The government is carefully considering the findings of the OCTAVE trial and will also consider any further appropriate advice — including from the independent Joint Committee on Vaccination and Immunisation (JCVI) — for those who are immunosuppressed as part of regular reviews of the latest data and evidence on vaccine efficacy and effectiveness.


Dr Michelle Willicombe, Principal Investigator of the trial at Imperial College Healthcare NHS Trust, said:

“The COVID-19 pandemic has been hugely concerning for us all. But even more so for the most clinically vulnerable.

“It is extremely important that we understand how best to vaccinate patients with chronic conditions. It’s imperative we do all we can to prevent these patients from catching COVID-19.

“It’s great that we have the OCTAVE DUO study opening at Hammersmith Hospital. Hopefully the outcomes will benefit patients very soon.”


Health and Social Care Secretary Sajid Javid said:

"Vaccines have built a strong wall of defence in the UK and this is allowing most of us to learn to live safely with COVID-19.

"We know some people may get less protection from the vaccine than others, so we are planning for a booster programme in the Autumn, prioritising those most at risk.

"This new study will play an important role in helping to shape the deployment of future vaccines doses for these specific at-risk groups."


A separate study by Public Health England in July which looked at antibody response and vaccine effectiveness against symptomatic infection also showed that those who were immunocompromised had lower antibody responses.

It also found that protection from COVID (vaccine effectiveness against symptomatic disease) for those who are immunosuppressed of all ages after one dose was 4%, but after two doses it was 74%, providing similar protection to those who are not in an at-risk group. Again vaccine effectiveness may vary by specific condition and severity of that condition.

Patients included in the OCTAVE DUO study are people with lymphoid malignancies, immune mediated inflammatory diseases (including rheumatoid arthritis, psoriatic arthritis, vasculitis and inflammatory bowel disease), renal disease, solid tumours (including breast and lung cancers), haematopoietic stem-cell transplantation, hepatic and intestinal disease, and primary immune deficiency.