Heterologous COVID Booster: No Better Response in Kidney Patients
(Reuters Health.) Kidney transplant recipients experience similar outcomes when they receive homologous and heterologous vaccine doses A random clinical study suggests.
Researchers conducted a randomization of 197 kidney transplant recipients who did not have antibodies to the SARS-Cov-2 spike protein after two doses of a virus mRNA vaccine made by Moderna or BioNTech/Pfizer. Patients were randomized 1:1 to receive either a homologous third vaccine dose or a heterologous third dose of the vaccine from Johnson & Johnson, combining mRNA and viral vector vaccines.
The primary endpoint of the study was seroconversion 4 weeks after the third dose of the vaccine; secondary endpoints included neutralizing antibodies and T-cell responses assessed by interferon-g release assays (IGRA).
Overall 39% of patients experienced an antibody response after the third dose. There was no statistically significant difference in response rate based on whether the third dose contained mRNA (35%) and vector (42%) vaccines.
“It did not surprise us that the homo- and heterologous strategies were about equally ineffective,” said senior study author Dr. Rainer Oberbauer of the Medical University of Vienna in Austria.
The study also revealed that only 22% of seroconverted patients had antibodies that neutralized them.
Researchers report in JAMA Internal Medicine that only 17 patients showed positive T-cell responses following the third vaccination.
When researchers examined what factors could influence the response to vaccines in patients, they discovered that those who received nontriple immunosuppression significantly more likely to develop antibodies (odds ratio 3.59). Patients also had significantly higher odds of developing antibodies following receiving nontriple immunosuppression (OR 1.44) and also with the presence of torque tenovirus in the plasma (OR 0.92 per increasing).
The frequency of discomfort at the injection site was higher with third doses mRNA vaccines than with vector vaccines however, the severity of side effects was similar between the groups.
The research team points out that the small sample size may have made it impossible for statistically significant differences to be being observed between groups. The criteria for inclusion was restricted to recipients of kidney transplants who were not responding to the initial two doses of mRNA vaccine. This could hinder generalization.
However, the results suggest that patients undergoing kidney transplants might benefit from a homologous or heterologous third dose of vaccine, Dr. Oberbauer said by email.
“Given our findings the actual choice of vaccine type is not important,” Dr. Oberbauer declared.
The medically required immunosuppression that is mandatory for kidney transplant patients performs in the way it is supposed to work by blocking rejection of the transplant, however in the context of SARS-CoV-2, it can hinder the development of immunity through vaccination, Dr. Oberbauer noted.
Dr. Oberbauer said, “The important take-home message is, however, that approximately one third of patients are seroconverted.” “Even although their levels of antibody were mainly low, they are likely to benefit from further vaccinations.”
SOURCE: https://bit.ly/3pzosez JAMA Internal Medicine, online December 20, 2021.