Metabolic acidosis; Weakness; This case was reported in a literature article and described the occurrence of metabolic acidosis in a adult patient who received Herpes zoster (Shingrix) for prophylaxis.   The subject's past medical history included allogenic stem cell transplantation.   On an unknown date, the patient received Shingrix (intramuscular) .5 ml. On an unknown date, less than a week after receiving Shingrix, the patient experienced metabolic acidosis (serious criteria hospitalization) and weakness (serious criteria hospitalization). On an unknown date, the outcome of the metabolic acidosis and weakness were unknown.   The reporter considered the metabolic acidosis and weakness to be possibly related to Shingrix.  Additional details were provided as follows: This case was reported in a literature article and described the occurrence of Metabolic acidosis; Weakness, in a patient of unspecified age and gender, who was vaccinated with Shingrix (GlaxoSmithKline) for prophylaxis.  The patient was a part of a single-center prospective observational cohort study that was conducted between December of 2018 and June of 2020 to evaluate the safety and reactogenicity of recombinant zoster vaccine (RZV) in adult allogeneic hematopoietic cell transplantation (HCT) recipients, including any effects on graft-versus-host disease (GVHD) occurrence or exacerbation given the presence of an adjuvant. The patient was more than or equal to 18-year-old at the time of allogenic HCT. The patient was between 9 to 24 months from time to transplant and was deemed appropriate for RZV by treating clinician. The patient did not have disease relapse prior to administration of the first dose of RZV vaccination (V1). No information on patient medical or family history or concurrent condition or concomitant medication was reported.  On an unknown date, the patient received 1 intramuscular dose (0.5 mL) of Shingrix (administration site unspecified, batch number not provided). The age at vaccination was not reported. [In this study, Cohort A consisted of patients who received V1 at 9 to 12 months after transplant in accordance with a hospital vaccination guidelines. Cohort B consisted of patients who received V1 at 12 to 24 months after transplant as part of a "catch-up" vaccination effort. RZV was given alongside other vaccines in the vaccine schedule. Patients were followed until June of 2020 and for more than or equal to 30 days after final vaccination. The primary end points were safety and reactogenicity in the total vaccinated cohort (TVC), which included all participants who received more than or equal to 1 vaccine dose. The secondary end points included incidence and severity of GVHD in the TVC compared with historical controls and the incidence rates of HZ in the TVC and modified TVC (mTVC), which included only patients who received both doses of the vaccine. Adult Post Hematopoietic Cell Transplant Vaccine Guidelines included: 9 months vaccine as DTaP, HiB, IPV, Prevnar, Shingrix; 12 months vaccine as DTaP, HiB, IPV, Prevnar, Menactra, Twinrix, Shingrix; 14 months vaccines as Hep B, Menactra; 18 months vaccines as DTaP, HiB, IPV, Prevnar, Twinrix and 24 months vaccines as MMR, Pneumovax]. On an unknown date, 3 days after vaccination (V1), the patient was hospitalized for metabolic acidosis and weakness. [In this study, HZ cases were defined as (1) a new rash that was characteristic (unilateral, dermatomal, painful, vesicular) and that was documented as HZ by a treating clinician or (2) an atypical rash or suspected disseminated VZV infection that was confirmed by VZV culture, direct fluorescent antibody detection, polymerase chain reaction, or immunohistochemical staining on tissue specimen. Patients who had HZ within 30 days of vaccine 2 (V2) were excluded from the mTVC analysis. A sensitivity analysis was performed looking at follow-up only in individuals who discontinued antiviral prophylaxis. During the study period, there were 5 deaths; they were secondary to disease relapse and infection and were not considered related to vaccination]. The case was considered as serious due to hospitalization. Treatment was unknown. Outcome of the event was not reported. The events were considered as possibly related to vaccination. The authors commented "Two doses of RZV demonstrated safety and tolerability in allogeneic HCT without increased rates of chronic GVHD (cGVHD), relapse, or death, as well as overall low rates of breakthrough. Vaccines were co-administered with RZV in the majority of participants which may have led to a higher incidence of solicited AEs than if RZV was administered alone. Although there have been concerns related to potential immune-mediated disorders (pIMDs) with the use of the RZV novel adjuvant AS01B system, there was no increased incidence or severity of cGVHD observed in the subgroup that was vaccinated between 9 and 12 months compared with historical controls in the peri-vaccination 9 to 15-month period. This finding is in keeping with renal transplant recipients who did not experience higher rates of solid organ rejection21 and healthy adults who did not have increased pIMDs after RZV. Patients on immunosuppression during vaccination had a higher incidence rate ratios (IRR) of cGVHD in the peri-vaccination period compared with those not on immunosuppression; however, they also likely represent a cohort with a higher baseline risk for alloreactivity.". The authors concluded "In summary, among recipients of allogeneic HCT, RZV was safe, tolerable, and did not increase rates of GVHD. There were few breakthrough cases of HZ in this cohort; however, future RCTs are needed to determine vaccine efficacy.". This article is not available for regulatory submission due to copyright restriction. This is 1 of the 6 valid cases reported in this literature article; Sender's Comments:  US-GLAXOSMITHKLINE-US2021GSK065760:Same reporter US-GLAXOSMITHKLINE-US2021GSK065761:Same reporter US-GLAXOSMITHKLINE-US2021GSK065762:Same reporter