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       Dr. Deepali Kumar, left, and Dr. Atul Humar are researchers at the University Health Network. A study by the hospital suggests a third dose of COVID-19 vaccine can boost protection in organ transplant recipients.

       HO/The Canadian Press

       New research suggests a third dose of a COVID-19 vaccine could help better protect organ transplant patients.

       Researchers at the University Health Network in Toronto say their study released today “shows a clear benefit” to offering a booster to this immunocompromised group.

       The study’s joint senior author Dr. Deepali Kumar says some transplant patients “are completely unprotected” with two doses and should be offered a third.

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       Researchers compared 60 participants in Ontario who received a third shot of the Moderna vaccine with 60 who got a placebo.

       Just over half, or 55 per cent, of those who received a third dose saw their antibody response rate reach at least 100 units per millilitre, which previous modelling suggests offers some protection.

       In comparison, 18 per cent of the placebo group reached 100 units.

       Dr. Kumar says antibody levels typically reach 1,000 to 10,000 units per millilitre in healthy people, and some of the transplant study participants showed similar numbers.

       The study is billed as the first randomized placebo-controlled trial of COVID-19 boosters in transplant patients.

       It was published today in the New England Journal of Medicine.

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