Organ Donor Marijuana Use Was Not Linked to Higher Early Infection Risk After Transplant
A history of recent marijuana use in a deceased organ donor was not associated with higher rates of donor culture positivity, post-transplant bacterial or fungal infections, graft failure, or death in a multicenter retrospective study.
The study published in the American Journal of Transplantation in 2024 examined 658 transplant recipients who received organs from 394 deceased donors at transplant centers in the United States. Researchers classified donors as having recent marijuana use if they had used cannabis within the previous 12 months.
Among donors with recent marijuana use, 89% had at least one positive bacterial or fungal culture, compared with 87% of donors without recent use. After adjustment for other factors, the difference was not statistically significant.
The researchers also found no meaningful association between donor marijuana use and bacterial or fungal infections in recipients during the first three months after transplantation. Of the 658 recipients, 38 developed an invasive fungal infection and 13 developed a mold infection. Donor marijuana use was not associated with either outcome. The same pattern held in the subgroup of 131 lung transplant recipients, who may be of particular concern because inhaled cannabis has been linked to fungal exposure.
Recipients whose organs came from donors with recent marijuana use also did not have significantly different rates of graft failure or death during the first year after transplantation. A separate analysis using donor toxicology results for THC likewise found no significant increase in recipient bacterial or fungal infections.
These findings address a specific concern: whether cannabis use by an organ donor creates an increased risk of transmitting bacterial or fungal infections through the donated organ. Cannabis products can become contaminated with fungi, and previous case reports and population-level research have raised concerns about fungal disease among people who use cannabis—particularly those with weakened immune systems. The Centers for Disease Control and Prevention’s analysis of commercially insured patients, for example, found an association between coded cannabis use and diagnosed fungal infections. That study could not determine whether cannabis caused the infections or identify how the patients had been exposed.
The transplant study, however, did not find evidence that a donor’s marijuana-use history translated into additional early infectious risk for organ recipients under current screening and clinical-management practices. The authors noted that the study may not have been large enough to detect relatively uncommon complications, and its retrospective design limits the conclusions that can be drawn.
The results also should not be interpreted as evidence that cannabis is risk-free for transplant patients. The study focused on marijuana use by deceased donors, not cannabis use by transplant recipients. Recipients remain vulnerable to serious infections, and transplant clinicians may also need to consider inhalational exposure, product contamination, and possible interactions between cannabis products and immunosuppressive medications. The American Society of Transplantation’s guidance on safe living after solid-organ transplantation advises recipients to discuss cannabis use with their transplant team and to avoid smoking cannabis because of potential infectious concerns.
Overall, the study supports evaluating donated organs according to the donor’s full clinical history, laboratory results, cultures, and the condition of each organ rather than treating a history of marijuana use alone as proof of an unacceptable infectious risk. Further research will be needed to determine whether the findings apply to longer-term outcomes, particular organ types, or different patterns of donor cannabis exposure.
