As immunosuppression and comorbidities predominantly afflict the solid organ transplant recipients, especially pediatric groups, COVID-19 is a matter of concern for many pediatric transplantation centers. At the moment, little is known about the exact impact of COVID-19 in solid transplant patient outcome. In our study, we retrospectively reviewed 51 pediatric transplanted patients after their surgery with a three month follow up. Our findings showed a slight reduction (26%) in the rate of transplantation in our center compared to last year as well as no COVID-19 involvement in the new organ recipients.
From the pediatric perspective, it could be assumed that children have a less severe disease in comparison to adults, and they corresponded with only 5% of the total number of patients involved with COVID-19 in China (12). While this could not be related to transmission chance since viral transmission in children is mentioned to be apparently similar to adult group in an epidemiological analysis by Qifang et al. of 391 cases and their 1286 close contacts (12).
Some hypotheses may explain the benign course of COVID-19 in pediatric cases compared with adults. First, viral clearance is more rapid in children which may lead to inflammatory response reduction which appears to be particularly important drivers of tissue damage during infection (13, 14). Second, children do not carry degenerative features of aging that is considered as COVID-19 risk factor(13, 14). Milder pattern of the disease may also be related to the lower maturity and the binding capacity of the angiotensin converting enzyme II, probably the virus cell receptor (13).
Immunocompromised patients’ reports are also few; this could illustrate their lower chance of involvement with the virus. Although earliest report of liver transplant children was available in Bergamo (15), their negligible symptoms suggested that the immunological impairment itself may be the cause of blunting the inflammatory cascades and cytokine release since the inflammatory reaction enhances the damage of the disease(6). Another case-control study by Chaudhry and his colleague on the clinical characteristics and outcomes of COVID-19 in solid organ transplant recipients associated the increasing age and clinical severity with mortality. While transplant status itself was not considered as a contributing factor with mortality(6). Another study demonstrated that Tacrolimus, widely used in transplant patients, strongly inhibited the growth of human coronavirus SARS-CoV, too (16). Furthermore, tight social distancing which is usually experienced by immunocompromised patients is considered as the main factor in their lower infection risks (17). Our preliminary experience, in agreement with recent data from of China and Italy which showed that none of the patients was followed for transplantation or autoimmune liver disease, developed a clinical pulmonary disease, except for some positive tests for SARSCoV-2. They assert that immunosuppressed patients are not at a higher risk of severe complications in comparison to the general population, both in children and adults (18).
Pediatric transplantation (0-17 years old) is a highly complex procedure that makes coordination of resources and specialized professionals of a great importance (19). A total rate of 108 pediatric transplant per year reported an activity of approximately 317 pediatric transplants from 2017 to 2019, while a 29.2% reduction was seen in this period in our center, which is compatible with the result of European centers that show COVID-19 pandemic substantial negative effect on pediatric transplantation activity as well as outpatient visits due to the fear of SARS-CoV-2 transmission risk, and shortage of hospital bed capacity and staff. On the other hand, it is noteworthy to mention the liver transplantation center of Hong Kong which shifted its resources to SARS patients during the SARS outbreak and performed no transplants for 6 months (20). This approach directly affected the quality of care in transplanted patients and liver transplant candidates though no case of severe pneumonia was also recorded (20). The long-term continuation of these limitations surely has dire consequences on pediatric transplant recipients as well as children on the transplant waiting list, reducing their access to close monitoring and follow ups. Therefore, optimizing the resource in specialized transplant center and establishing guidelines in terms of pediatric transplant recipients and candidates during the COVID-19 pandemic are required. D’antiga also suggested that coronaviruses have not been shown to cause a more
severe disease in immunosuppressed patients, so that there is no reason to postpone lifesaving treatments, such as transplantation, both in children and in adults during coronavirus outbreaks (15).
However, as the only pediatric transplant center in the country, our centers had to remain active during the period and the living donor was reserved for urgent cases, while cadaveric donors were available with specific adaptations of the protocols for COVID-19 screening, although in both cases the accessibility was notably reduced. For complex patients, prioritization of which patients in the list for transplant in the period is regarded to Higher PELD score and acute liver failures. Besides, outpatient activities are continued both in person, and through telemedicine. In our protocol, a normal spiral chest CT as well as two negative nasopharyngeal swabs for SARS-CoV-2 with 48-hour interval were taken from both living donors and recipients before planned hospitalizations or procedures which exclude 6 donors from the list due to their positive PCR test.
There is no final opinion regarding pre-transplant evaluation. Some centers use PCR and some Antibody test, while others only rely on spiral chest CT(21, 22). The timing of tests varies from one week to one day before transplant in different studies(23). In our study, the donor was excluded from transplant list if he/she presented with a positive PCR test, while other centers checked if PCR became negative or Antibody was presented (24).
This study has limitations. Since we are the only pediatric transplant center in Iran, our results cannot be compared with other less equipped centers to generalize. Even though our median follow-up was three months, long-term follow up needs further studies.