Background Immunocompromised COVID-19 patients have prolonged infectious viral shedding for more than 20 days. A test-based approach is suggested for de-isolation of these patients. Methods We evaluated this strategy by comparing SARS-CoV-2 viral load (Ct values) and viral cultures at the time of hospital discharge in a series of immunocompetent (6 patients) and immunocompromised (5 solid organ transplants, 1 patient with lymphoma and one patient with hepatocellular carcinoma) COVID-19 patients. Results 3/13 (23%) patients had positive viral cultures: one patient with lymphoma at day 16 and two immunocompetent patients at day 7 and 11. Of the patients, 80% had negative viral cultures and had mean Ct value 20.5. None of the solid organ transplants recipients had positive viral cultures. Conclusion The mean Ct values for negative viral cultures was 20.5 in our case series of immunocompromised patients. Unlike hematological malignancies, none of the solid organ transplants had positive viral cultures. Adopting the test-based approach for all immunocompromised patients may lead to prolonged quarantine. Large scale studies in disease specific populations are needed whether a test-based approach versus a symptom-based approach or a combination is applicable for the de-isolation of various immunocompromised patients.

The outcome of transplant recipients is variable depending on the study population, vaccination status and COVID-19 variants. Our aim was to study the impact of Omicron subvariants on the mortality of transplant recipients. We reviewed the results of SARS-CoV-2 whole genome sequence of random isolates collected from 29 December 2021 until 17 May 2022 in King Faisal Specialist Hospital and Research center, Jeddah (KFSHRC-J), Saudi Arabia performed as hospital genomic surveillance program for COVID-19 variants. We included 25 transplant patients infected with confirmed Omicron variants.17 (68%) and 8 (32%) patients had Omicron BA.1 and BA.2, respectively. 12 (68%) patients had renal transplants. Only 36% of patients received three doses of COVID-19 vaccines. 23 (92%) patients required hospitalization. 20 (80%) patients survived and 6 (25%) required intensive care unit (ICU) admission. Among ICU patients, 66.7% were more than 50 years, 50% had two to three comorbidities and 5 out of 6 (83%) died. The mortality of transplant patients infected with Omicron variants in our cohort was higher than other centers as a limited number of patients received booster vaccines. Optimizing booster vaccination is the most efficient method to improve the mortality of COVID-19 in transplant recipients recognizing the inefficacy of monoclonal antibodies in the presence of SARS-CoV-2 emerging variants. We did not show a difference in mortality in transplant patients infected with Omicron BA.1 and BA.2 knowing the limitation of our sample size.

Various studies have shown that SARS-CoV-2 is a highly immunogenic virus. It is known that different types of immunogenic viral pathogens could trigger the formation of HLA antibodies. Therefore, there is a concern that the SARS-CoV-2 could also induce the development of HLA antibodies in volunteers, who donate convalescent plasma after their recovery from COVID-19. HLA antibodies have been identified as the main cause for transfusion related acute lung injury, a well-documented life-threatening complication of transfusions. The TRALI risk could be high in COVID-19 patients who need convalescent plasma, as such patients usually have already an impaired respiratory system affected by the SARS-CoV-2 infection. In this study, we screened 34 convalescent plasma donors on the presence of antibodies against HLA class I and II antigens. All included donors have no any history of sensitization events such as blood transfusions, pregnancy, or previous transplants. We found a high rate of HLA antibody formation in convalescent plasma donors. The frequency of positivity for HLA antibodies for class I, class II, class I and II and the overall reactivity was 23%, 31%, 46% and 76% respectively. The presented data suggest a closed correlation between SARS-CoV-2 virus infection and the development of HLA antibodies in recovered convalescent plasma donors. This finding might have the potential to reduce the risk of TRALI and mortality rate in COVID-19 patients by implementing HLA diagnostic strategies before the administration of convalescent plasma.

Background COVID-19 vaccination effectively decreased hospitalization and mortality during the surge of infections with the SARS-CoV-2 Omicron variant. However, patients infected with the Omicron variant who did not receive a third COVID-19 vaccine booster often required critical care unit (CCU) admission. The CCU bed utilization of COVID-19 posed a worldwide burden. The decision to stop isolation of patients with COVID-19 in CCUs is challenging, given the variable viral shedding in heterogeneous patient populations. Rapid antigen detection tests (RADTs) have been used in communities to determine patients’ infectiousness and need for quarantine. However, the use of RADTs in the de-isolation of CCU patients had not been studied. Methods Serial RADTs, RT-PCR and viral culturing were performed in a case series of three critically ill patients infected with Omicron variants. Results The duration of infectious viral shedding was 13–46 days post symptom onset (PSO). Concordant negative results were observed between RADTs and viral cultures on D32 PSO in case 1; D13 and D15 PSO in case 2; and D46 and D48 PSO in case 3. In addition, concordant positive results were found between RADTs and viral cultures on D35 PSO in case 2. Significant agreement was observed between RADT and viral culture findings (kappa statistic = 1.0 and p-value = 0.014). Conclusion Given their high positive predictive value with respect to positive viral cultures, RADTs may be a promising and practical tool for ending isolation of patients with COVID-19 and decreasing the burden of CCU bed utilization. Future studies are necessary to confirm our findings.

Many uncertainties exist regarding COVID-19 vaccination in patients undergoing treatment for hematological malignancies. We intend the illustrate the various types of COVID-19 vaccine currently in use and their mechanism of action. We have complied, recommendations for COVID-19 vaccination in patients suffering with specific hematological malignancies and those undergoing HCT and CAR-T cell therapy in this review. We have also discussed the available safety data for COVID-19 vaccination in the immunocompromised population.