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Background: Hematopoietic stem cell transplant (HSCT) recipients are at increased risk of mortality and morbidity with coronavirus disease 2019 (COVID-19) due to severe immune dysfunction. Methods:A literature search was performed on PubMed, Cochrane, and Clinical trials.gov from the date of inception to 12/08/2021. We identified 19 original studies reporting data on COVID-19 in HSCT recipients after screening 292 articles.Data were extracted following preferred reporting items for systematic reviews and meta-analysis guidelines. Quality evaluation was done using the National Institutes of Health (NIH) quality assessment tool. Inter-study variance was calculated using Der Simonian-Laird Estimator. Pooled analysis was conducted using MetaXL. A randomeffects model was used to estimate the proportions with 95% confidence intervals (CI).Results: Of 6711 patients in 19 studies, 2031 HSCT patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection were analyzed. The median age of patients was 56.9 (range 1-81.6) years, and 63% patients were men according to 14 studies. The median time from transplant to SARS-CoV-2 infection for autologous (auto) and allogeneic (allo) HSCT patients was 23.2 (0.33-350.5) months and 16.4 (0.2-292.7) months, respectively. The median follow-up time after COVID-19 diagnosis was 28 (0-262) days. The COVID-19 mortality rate was 19% (95% CI 0.15-0.24, I 2 = 76%, n = 373/2031). The pooled mortality rate was 17% (95% CI 0.12-0.24, I 2 = 78%, n = 147/904) in auto-HSCT patients and 21% (95% CI 0.16-0.25, I 2 = 60%, n = 231/1103) in allo-HSCT patients.Conclusions: HSCT recipients have a high risk of mortality and clinical complications due to COVID-19. There is a need for ongoing vigilance, masks, and social distancing, vaccination, and aggressive management of SARS-CoV-2 infection in HSCT recipients.

Eclogites of the Kaghan valley, Pakistan Himalaya were investigated petrographically and geochemically. Based on petrography, geochemistry and mineral compositions, metamorphic history and a reasonable tectonic model are proposed. Eclogites exposed in the Kaghan valley are classified into two groups. Group I eclogites appear as massive and Group II are lens -type. Group I eclogites have a mineral assemblage of garnet, omphacitic clinopyroxene, quartz, symplectite with rare epidote and phengite. Accessory minerals include abundant zircon, rutile, ilmenite, and rare apatite. Group II eclogites have a mineral assemblage of garnet, omphacitic clinopyroxene, phengite, quartz/coesite, epidote, and symplectite. In accessory minerals rutile and ilmenite are common while zircon and apatite are rare. Different types of protolith are proposed for these eclogites. Group I eclogites have higher FeO and TiO 2 contents and trace element contents, and seem to be derived from gabbroic protolith. Group II eclogites have lower FeO and TiO 2 and trace element contents and were derived from basalts. Pressure -temperature -time path was constructed for the Kaghan valley eclogites using various mineral assemblages along with textural relationship and inclusions study. At least three distinct metamorphic stages were identified. The first stage is the prograde garnet growth stage deduced from the inclusion paragenesis in garnet core. The second stage records the ultrahigh -pressure metamorphic stage deduced from the presence of coesite inclusions in omphacitic clinopyroxene. The third stage is the decompression stage and is deduced from the quartz -albite -amphibole symplectite portions. These petrological and geochemical results combined with isotopic ages reported elsewhere indicate that basalts and associated gabbroic dikes were emplaced at about 267 Ma when the Indian plate was moving northward and passing above an unknown hot spot. The closure of the Tethys and initiation of collision of the Indian plate with the Kohistan -Ladakh Island Arc is reported from 65 -50 Ma. After that the leading -edge of the Indian plate underwent eclogite facies metamorphism at 49 Ma and when it reached to depths of about 100 km, the ultrahigh -pressure metamorphic event took place at 46 Ma.

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