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Three doses of COVID-19 vaccine leads to catch-up antibody responses among the particularly vulnerable, finds study

Three doses of COVID-19 vaccine leads to catch-up antibody responses among the particularly vulnerable
Antibody response to COVID-19 mRNA vaccination with and without COVID-19 during the study period. Scatter plots with mean and 95% confidence interval demonstrating logarithmic IgG antibody levels in serum against the receptor-binding domain (RBD) within spike-1 (S1) among patients with liver disease with (A) or without cirrhosis (B; autoimmune hepatitis) as well as allogeneic hematopoietic stem-cell transplantation recipients (C) and healthy controls (D). Patients are stratified as to whether they acquired a SARS-CoV-2 Omicron subvariant infection following the second vaccine dose (i.e. developed hybrid immunity (HI), open circles) or not (i.e. only vaccine-induced immunity (VII), gray filled circles for those receiving 3 and black filled circles for those receiving 4 vaccine doses). The dotted line represents the limit of detection of the assay (i.e. 14 BAU/mL). Statistics were calculated by unpaired t-test with Welch's correction (*p < .05, ***p < .001, ****p < .0001, ns = not significant) and paired t-test on logarithmic values (#p < .05, ##p < .01, ###p < .001, ns = not significant). Credit: Infectious Diseases (2023). DOI: 10.1080/23744235.2023.2230289

Even vulnerable people, who are at risk of severe COVID-19, achieved good antibody levels after three doses of mRNA vaccine. This is shown by a study from the University of Gothenburg on patients having undergone a bone marrow transplant or with liver disease, including cirrhosis.

The aim of the study, which has been published in the journal Infectious Diseases, was to investigate the effects of repeated vaccinations and hybrid immunity against COVID-19 among particularly vulnerable individuals. Hybrid immunity refers to the protection provided by vaccination in combination with SARS-CoV-2 infection.

The results demonstrate how levels of COVID-19 antibodies build up following each successive vaccine dose in those with a fundamentally deficient immune defense. This is a field where there remains limited knowledge.

Equivalent after the third dose

The study included 38 patients with , 36 recipients, 14 patients with autoimmune liver disease, and 20 healthy controls. All patients were cared for at Sahlgrenska University Hospital in Gothenburg, Sweden.

The patients were monitored for COVID-19 antibodies after their first, second, third, and for some bone marrow transplant recipients, their fourth vaccine doses. None of the participants had had COVID-19 before the second dose, but 31 of them had a mild COVID-19 omicron variant infection between the second and third doses.

Those with deficient immune defense due to or having received a bone marrow transplant had less protection than the controls up until after the second dose of the vaccine. Following the , however, the groups had equivalent levels of antibodies.

Regardless of their level of underlying immunity, all groups included in the study showed antibody levels that were ten times higher after COVID-19 infection compared to those who had acquired their immunity through vaccination alone.

Unexpectedly good protection among the vulnerable

Three doses of mRNA vaccine against COVID-19 thus resulted in high antibody concentrations even in immunocompromised individuals, and hybrid immunity resulted in even higher levels.

Martin Lagging is a Professor in Clinical Virology at the University of Gothenburg's Sahlgrenska Academy, a senior physician at Sahlgrenska University Hospital, and the study's last author.

"It was unexpected—but extremely pleasing—to note that vulnerable individuals achieved antibody levels on a par with the healthy ones after three doses of vaccine," he explains. "This underlines the importance of continuing to vaccinate, even if the is poor after the first doses."

More information: Samer Al-Dury et al, Catch-up antibody responses and hybrid immunity in mRNA vaccinated patients at risk of severe COVID-19, Infectious Diseases (2023). DOI: 10.1080/23744235.2023.2230289

Citation: Three doses of COVID-19 vaccine leads to catch-up antibody responses among the particularly vulnerable, finds study (2023, August 1) retrieved 19 July 2024 from
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