Background Despite Toxoplasma seropositivity found in about one-third of the global population, we lack information about the clinical outcomes of patients with past exposure to this parasite without the manifested disease. We aim to evaluate 1-year mortality and mental health diagnosis in patients with Toxoplasma IgG seropositivity. Methods We queried a federated national multicenter network to validate mortality risk differences between Toxoplasma IgG seropositive and seronegative patients from 2010 to 2021, excluding patients with active disease. We used propensity score matching to assess independent mental health outcomes and mortality risk 1-year after serology. Results We found 6244 patients with Toxoplasma IgG positivity without toxoplasmosis and 29,179 patients with negative Toxoplasma IgG. Patients with positive Toxoplasma IgG were slightly older (46.1 ± 17 vs. 45±16.5, p< 0.0001) and more likely to be Hispanic (15% vs. 12%, p< 0.0001). Toxoplasma gondii IgG seropositivity was more often present in patients with neoplasms (25% vs 22%, < 0.0001), type 2 diabetes mellitus (13% vs 12%, p=0.0284), and less likely in transplant recipients (7% vs. 8%, p=0.0015), and liver cirrhosis (5% vs 7%, p. < 0.0001). Propensity score matching to 6099 seronegative patients adjusted for age, gender, race, ethnicity, heart disease, transplant, neoplasm, and cirrhosis found that seropositive patients had an increased risk of 1-year mortality (OR: 1.2, CI: 1.06-1.4, p=0.0036) (Figure 1), hospitalization (OR:1.2, CI: 1.1-1.3, p< 0.0001) and schizophrenia (OR: 1.4, CI: 1.01-1.8, p=0.04). An increased risk was not seen with bipolar disorder (OR: 0.86, CI: 0.66-1.15, p=0.3206). Figure 1.Kaplan-Meier survival analysis comparing the survival probability of patients without toxoplasmosis with a positive toxoplasma IgG (purple line) to those with a negative Toxoplasma IgG (green line) Conclusion Toxoplasma IgG seropositivity without clinical disease is associated with an increased risk of one-year mortality, hospitalization, and schizophrenia diagnosis. Further prospective studies are needed to clarify the association of Toxoplasma exposure with schizophrenia and worse outcomes. Disclosures All Authors: No reported disclosures.

Background Streptococcus pyogenes causes acute pharyngitis and type II necrotizing fasciitis. Seasonal variations in the incidence of S. pyogenes infections are not robustly characterized. We aim to identify seasonal variations and risk factors of S. pyogenes infections and all causes of necrotizing fasciitis. Methods From 2010 to 2019, we identified all infectious adult cases of S. pyogenes using ICD-10 diagnoses and lab results (PCR and antigen-based assays) and cases of necrotizing fasciitis using ICD-10 diagnoses within a federated research network. We extracted seasonal (quarterly) incidence rates. We used an autoregressive integrated moving average (ARIMA) model to assess the seasonality of the cases (6-month intervals). Demographic characteristics and 3-month outcomes of S. pyogenes pharyngitis were compared to a cohort of patients with acute upper respiratory illnesses excluding S. pyogenes. Results We identified 238,088 cases of S. pyogenes pharyngitis and 26,931 cases of necrotizing fasciitis in adults. S. pyogenes infection average incidence was higher during the winter than the summer: 0.34 vs. 0.20 cases per 1,000 patients. Necrotizing fasciitis diagnoses were highest during the summer months (average 0.026 per 1000 patients). There was a significant ARIMA seasonal variation in the time series analysis for S. pyogenes infections (p=0.006) (figure 1). However, necrotizing fasciitis was not significant (p=0. 0.79) (Figure 2). Compared to adults with acute respiratory infections other than S. pyogenes, adults with S. pyogenes pharyngitis were more likely to be younger (25.8 ± 14.9 vs. 45.4 ± 19.9 years old, p< 0.0001) and of Hispanic or Latino ethnicity (11% vs. 8%, p < 0.0001). For age-matched outcomes, adults with S. pyogenes pharyngitis had lower rates of hospitalization (0.888% vs. 1.714%, p< 0.0001) and mortality (0.114% vs. 0.174%, p< 0.0001) at three months relative to adults with acute respiratory infections other than S. pyogenes. Figure 1.Seasonal variation of adults with established ICD code or testing for Streptococcus pyogenes (GAS) infectionsFigure 2.Seasonal variation of adults with established ICD code for necrotizing fasciitis Conclusion Peaks in S. pyogenes infections are more likely to occur in the winter months, although spring and fall seasons can display variably high rates of S. pyogenes year over year. Necrotizing fasciitis of any microbiological did not show a significant seasonal variation. Disclosures All Authors: No reported disclosures.