SARS-CoV-2 vaccine effectiveness trumps immunogenicity in solid organ transplant recipients.

DISCLOSURE

The author of this manuscript has no conflicts of interest to disclose as described by the American Journal of Transplantation.

To the Editor:

On June 8, Malinis et al, published their preliminary observations of the SARS‐CoV‐2 vaccine effectiveness in solid organ transplant recipients (SOTR) in the AJT. Their timely, real world results based on current practices are reassuring.

Several studies have now shown 100% effectiveness of multiple SARS‐CoV‐2 vaccines in preventing hospitalization and death. As of May 17, 2021, 860 of 123 million (0.0008%) who were fully vaccinated developed breakthrough infections that required hospitalization or were fatal. The study by Malinis et al shows a 0.65% rate of breakthrough infections; all of which were mild, and none that required hospitalization or were fatal. Importantly, authors do not recommend cessation of precautionary measures.

The study by Malinis et al has some limitations. This study did not include SOTR ≤16 years of age, and 70% were kidney recipients. Results may not apply to lung, multivisceral, or composite tissue transplant recipients, who are at higher risk of respiratory infections either due to higher degrees of immunosuppression, or direct communication between the transplanted organ and the environment. The study included SOTR without documented SARS‐CoV‐2 infection, so patients with prior asymptomatic infections and thus possibly partially protected may have been included in this study. While a SARS‐CoV‐2 serologic testing has many caveats, an antibody test specific to infection could identify those who may be partially protected. The median time interval between transplant and infection was 4.6 years, so the results may not apply to SOTR receiving the vaccine early after transplantation. The study does not describe vaccine side effects in SOTR, does not report on rates of rejection, or types of immunosuppressive medications used. The study only reports a short follow‐up interval after breakthrough infection.

A prospective cohort of fully immunized HCP, first responders, and other essential and frontline workers who completed weekly SARS‐CoV‐2 testing for 13 consecutive weeks, showed an incidence rate for breakthrough infections of 0.04 per 1000 person‐years.

A joint statement published on May 7, 2021 by multiple transplant societies urged continued SARS‐CoV‐2 vaccination of SOTR, their household members and caregivers, and continued adherence to protective behavioral measures.

Emerging data suggest effectiveness of the current COVID‐19 vaccines against viral variants. This should apply to SOTR as well.

Future studies should focus on fully vaccinated SOTR, and separately analyze breakthrough infections that are mild and those that require hospitalization or are fatal. Data assessing long‐term vaccine effectiveness, resource utilization, cost‐effectiveness, and impact on the rates of rejection, and opportunistic infections should also be considered.