Strong evidence to support use of third primary vaccine dose in people with weakened immune systems, UK Covid Vaccine Research Hub

New research from the team behind the COV-AD study has uncovered ' strong data ' to support the policy of giving a third primary dose of vaccine to people with weakened immune systems. The study, published as a preprint, looked at immune responses in 161 people with immune deficiency, with blood samples being taken at various timepoints before and after their third dose of vaccine. People with both primary and secondary immunity were included in the study – primary immunodeficiency occurs as a result of genetic factors, while secondary immunodeficiency is usually caused by illness. The results were compared with those of a control group of 205 people without immune deficiency. The proportion of people with immune deficiency who had a detectable an tibody response rose from 61% to 76% after a third dose of vaccine. The proportion with antibodies capable of neutralising the Omicron variant rose from 40.5% to 67.5%. The strength of the antibody response also increased after the third dose. These effects were seen in people with both primary and secondary immunodeficiency, and the response to the third dose was similar regardless of whether the person had the AstraZeneca or Pfizer vaccine for their first two doses. Crucially, a third dose triggered a detectable antibody response in some people who had not responded to their first two doses of vaccine.
Source: Current Awareness Service for Health (CASH) - Category: Consumer Health News Source Type: news