Strategies to modify production, specification, and storage of blood components to help prevent blood shortage Red blood cellsExtend shelf life if validated and within regulations Review manufacturing process. 64,65 Platelets Extend shelf life from 5 days to 7 days with appropriate bacterial testing or pathogen inactivation Recovery and survival of platelets, as well as count increments following transfusion, decline with increasing storage duration. 66,67 Bacterial risk depends on the timing of sampling, sample volume, and the length of culture; delayed culture methods with 7 day storage have been shown to be effective. 68 Depending on screening methodology, a further test at day 4 or at the end of storage might be required.Extend shelf life to 8 days after review of internal laboratory data to guide feasibility Review internal laboratory data to guide feasibility, and review data on bacterial risk. There is scant clinical data beyond day 7. At day 8, the recovery of fresh platelets manufactured from buffy-coats is nearly 70% and platelet survival is 45%. 69,70 Improved recovery and survival of platelets with prolonged storage has been observed with some types of additive solution. 69,70 Reduce dose for prophylactic transfusion (split products) Some countries already issue split products for neonatal transfusion. Consider half doses, or methods to produce two-thirds to three-quarter doses, such as pooling fewer so-called buffy coats or splitting aphaeresis collections into more doses. 71 Consider use of cold-stored platelets with 7-14-day shelf life for patients with bleeding only Studies in healthy volunteers suggest that the survival of platelets from whole blood or platelet concentrates refrigerated for 10-15 days might maintain acceptable viability. Laboratory data suggest that platelets remain functional for 14-21 days without the need for agitation. 72,[73][74][75][76] Consider frozen platelets for bleeding patients only 77,78 Plasma Remove requirements to freeze plasma Consider use of liquid (never frozen) plasma if freezer capacity or staff to freeze plasma are in short supply. 79 Whole BloodUse of whole blood Consider if staff to manufacture components are in short supply or for massive transfusion. [80][81][82][83][84]

Growing evidence suggests that ABO blood group may play a role in the immunopathogenesis of SARS‐CoV‐2 infection, with group O individuals less likely to test positive and group A conferring a higher susceptibility to infection and propensity to severe disease. The level of evidence supporting an association between ABO type and SARS‐CoV‐2/COVID‐19 ranges from small observational studies, to genome‐wide‐association‐analyses and country‐level meta‐regression analyses. ABO blood group antigens are oligosaccharides expressed on red cells and other tissues (notably endothelium). There are several hypotheses to explain the differences in SARS‐CoV‐2 infection by ABO type. For example, anti‐A and/or anti‐B antibodies (e.g. present in group O individuals) could bind to corresponding antigens on the viral envelope and contribute to viral neutralization, thereby preventing target cell infection. The SARS‐CoV‐2 virus and SARS‐CoV spike (S) proteins may be bound by anti‐A isoagglutinins (e.g. present in group O and group B individuals), which may block interactions between virus and angiotensin‐converting‐enzyme‐2‐receptor, thereby preventing entry into lung epithelial cells. ABO type‐associated variations in angiotensin‐converting enzyme‐1 activity and levels of von Willebrand factor (VWF) and factor VIII could also influence adverse outcomes, notably in group A individuals who express high VWF levels. In conclusion, group O may be associated with a lower risk of SARS‐CoV‐2 infection and group A may be associated with a higher risk of SARS‐CoV‐2 infection along with severe disease. However, prospective and mechanistic studies are needed to verify several of the proposed associations. Based on the strength of available studies, there are insufficient data for guiding policy in this regard.

This document aims to provide practical guidance for the assessment and management of patients with thrombocytopenia, with a particular focus on immune thrombocytopenia (ITP), during the COVID-19 pandemic. The intention is to support clinicians and, although recommendations have been provided, it is not a formal guideline. Nor is there sufficient evidence base to conclude that alternative approaches to treatment are incorrect. Instead, it is a consensus written by clinicians with an interest in ITP or coagulation disorders and reviewed by members of the UK ITP forum.