Early experience with SARs‐CoV‐2 mRNA vaccine breakthrough among kidney transplant recipients

Abstract

The efficacy of vaccinations among vulnerable populations such as solid organ transplant recipients on chronic immunosuppression have been suboptimal compared to the general population.1, 2 Preliminary data suggest the humoral response rate for solid organ transplant patients who have received both doses of SARs-CoV-2 mRNA vaccine either mRNA-1273 (Moderna) or BNT162b2 (Pfizer-BioNTech) is roughly 54%.3 However the clinical implications and real-life impact of this is still unknown. Here we present our early single-center experience with vaccine breakthrough and symptomatic COVID-19 (Coronavirus Disease-2019) disease hospitalization rates in fully vaccinated kidney transplant recipients. A total of 166 kidney transplant recipients were diagnosed with symptomatic COVID-19 at our health system from March 2020 to April 2021. Of these 107 (64%) required inpatient admission and overall mortality was 11% (18/166). Three hundred and eighty (mostly age > 65 years) completed both doses of the Pfizer-BioNTech or Moderna vaccine by April 2021. From February to April there were 17/166 (10%) new positive documented COVID-19 cases. Among them 7/17 patients developed symptomatic disease despite being fully vaccinated suggesting an early breakthrough rate of 1.8% (7/380). Four out of seven were hospitalized; however only two developed severe COVID-19 symptoms requiring supplemental oxygenation redemsivir and dexamethasone. Further clinical details are provided in Table 1. These patients were predominately male (5/7) with a median age of 53 who received a deceased donor with a median time of 3 years from transplant. Majority (6/7) were maintained on triple immunosuppression with one patient taken off of anti-metabolite due to persistent BK viremia. Median time from vaccine completion to time to diagnosis was 33 days. Interestingly 3/7 patients had detectable Sars-CoV-2 spike IgG antibody while 2/7 had both spike and nucleocapsid protein IgG at the time of COVID-19 diagnosis. Unfortunately quantitative antibody levels as well as SARs-CoV-2 variant data was not available. Our early experience suggests limited early breakthrough COVID-19 in kidney transplant recipients who completed the two-dose SARs-CoV-2 mRNA vaccine series despite a reported 54% antibody response. In patients who did experience vaccine breakthrough the majority did not develop severe symptoms that required inpatient admission. This may reflect a need for quantitative antibody disease protection threshold measurements as well as the importance of continued vaccine efforts among immunosuppressive patients despite the reported lower antibody response. Our results are further strengthened by a significant decline in the diagnosis of new COVID-19 cases since vaccinations started. Future studies are needed to assess newer strategies in vaccination to better protect immunosuppressed patients from preventable morbidity and mortality. The authors do not have any potential conflicts of interests to disclose. The authors do not have any potential conflicts of interests to disclose.

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