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covid booster 'best way' to protect transplant patients
two vaccine doses isn't enough to protect people who have had organ transplants: study
aug 12 2021
3 minute read
the study also examined the effectiveness of the immune response to the third dose.
getty
organ transplant patients who received a third dose covid-19 booster vaccine experienced a significant improvement in protection against the virus, according to a new study that says the added measure is vital for vulnerable populations.
the research, conducted at toronto’s ajmera transplant centre and published in the new england journal of medicine , was the first in the world to employ a randomized double-blind placebo-controlled study — the gold standard for obtaining accurate results in medical research. such studies typically take a year to complete but the team said it worked around the clock to complete its work in a fraction of the time.
in a world-first study published in @nejm, researchers at the ajmera transplant centre at uhn (@uhntransplant) have discovered that a third dose of #mrnavaccine is safe & effective in boosting protection against #covid19 for #transplant patients.
— university health network (@uhn) august 12, 2021
more → https://t.co/xmcuzqmm4u pic.twitter.com/aqaniigyfo
“we knew from previous studies that two doses were not enough to produce a good immune response against covid-19 in transplant patients,” said dr. deepali kumar , joint senior author of the study and director of transplant infectious diseases for the university health network in toronto. “based on our study, a third dose of covid vaccine is definitely the best way to increase protection in transplant recipients.”
to test the viability of a third shot, researchers recruited 120 transplant patients at the end of may who had not contracted the virus and had received two shots of the moderna vaccine. two months after their second shot, half of the participants were given a third shot of the vaccine while the other half received a placebo.
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based on the detection of antibody levels exceeding 100 u/ml against covid-19’s spike protein, the response rate in the vaccine group was 55 per cent compared to just 18 per cent in the placebo group. “this is an important win for our patients because the results are quite conclusive,” said atul humar, joint senior author of the study and medical director of the ajmera transplant centre. “the third dose was safe and well tolerated and should lead to a change in practice of giving third doses to this vulnerable population.”
the study also examined the effectiveness of the immune response to the third dose and found 60 per cent of patients developed neutralizing antibodies compared to just 25 per cent of patients in the control group. they also detected a discrepancy between groups in the t-cell response — another arm of the immune system that battles severe disease — with recipients of the third dose producing a more robust response.
perhaps most importantly, patients experienced only mild side effects to the third jab and no acute organ rejections — a key concern ahead of the study. the rigorous pace of research allowed the team to quickly compile its findings and pass them along to interested regulatory bodies, including the u.s. food and drug administration, the canadian national advisory committee on immunization and the american society of transplantation.
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“we were able to do this because our team worked non-stop for months,” humar said. “and we are in a global emergency, lucky enough to have generous philanthropic donors and an existing vaccine trials infrastructure already set up.”
a record number of patients received organ transplants in ontario in 2019, according to figures from the trillium gift of life network. health teams performed 1,386 organ transplants and 684 deceased and living patients donated organs, which represents a 13 per cent increase over a year earlier. both transplants and donations represent new records in the province.
the team, which has received $2.8-million in funding from the government of canada to continue its research at transplant centres across the country, said it hopes to receive expedited approval to begin treating vulnerable patients as soon as possible.
dave yasvinski is a writer with healthing.ca
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