Repeated positivity and reinfection with severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) is a significant concern. Our study aimed to evaluate the clinical significance of repeatedly positive testing after coronavirus disease 2019 (COVID-19) recovery. We performed a systematic literature search following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. With available individual patient data reporting on repeatedly SARS-CoV-2 positive (RSP) patients, case reports, and case series were included in this analysis. We performed a descriptive analysis of baseline characteristics of repeatedly positive cases. We assessed the cases according to the length of their polymerase chain reaction (PCR) negative interval between the two episodes. Risk factors for the severity of second episodes were evaluated. Overall, we included 123 patients with repeated positivity from 56 publications, with a mean repeated positivity length of 47.8 ± 29.9 days. Younger patients were predominant in the delayed (>90 days) recurrent positive group. Furthermore, comparing patients with RSP intervals of below 60 and above 60 days, we found that a more severe disease course can be expected if the repeated positivity interval is shorter. Severe and critical disease courses might predict future repeatedly positive severe and critical COVID-19 episodes. In conclusion, our results show that the second episode of SARS-CoV-2 positivity is more severe if it happens within 60 days after the first positive PCR. On the other hand, the second episode’s severity correlates with the first.

Background: Acute gastrointestinal bleeding (GIB) is a life-threatening event. Around 20–30% of patients with GIB will develop hemodynamic instability (HI). Objectives: We aimed to quantify HI as a risk factor for the development of relevant end points in acute GIB. Design: A systematic search was conducted in three medical databases in October 2021. Data sources and methods: Studies of GIB patients detailing HI as a risk factor for the investigated outcomes were selected. For the overall results, pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated based on a random-effects model. Subgroups were formed based on the source of bleeding. The Quality of Prognostic Studies tool was used to assess the risk of bias. Results: A total of 62 studies were eligible, and 39 were included in the quantitative synthesis. HI was found to be a risk factor for both in-hospital (OR: 5.48; CI: 3.99–7.52) and 30-day mortality (OR: 3.99; CI: 3.08–5.17) in upper GIB (UGIB). HI was also associated with higher in-hospital (OR: 3.68; CI: 2.24–6.05) and 30-day rebleeding rates (OR: 4.12; 1.83–9.31) among patients with UGIB. The need for surgery was also more frequent in hemodynamically compromised UGIB patients (OR: 3.65; CI: 2.84–4.68). In the case of in-hospital mortality, the risk of bias was high for 1 (4%), medium for 13 (48%), and low for 13 (48%) of the 27 included studies. Conclusion: Hemodynamically compromised patients have increased odds of all relevant untoward end points in GIB. Therefore, to improve the outcomes, adequate emergency care is crucial in HI. Registration: PROSPERO registration number: CRD42021285727.

Background: Acute pancreatitis (AP) has a high incidence, and patients can develop recurrent acute pancreatitis (RAP) and chronic pancreatitis (CP) after AP. Objectives: We aimed to estimate the pooled incidence rates (IRs), cumulative incidences, and proportions of RAP and CP after AP. Design: A systematic review and meta-analysis of studies reporting the proportion of RAP and CP after AP. Data sources and methods: The systematic search was conducted in three (PubMed, EMBASE, and CENTRAL) databases on 19 December 2023. Articles reporting the proportion of RAP or CP in patients after the first and multiple episodes of AP were eligible. The random effects model was used to calculate the pooled IR with 95% confidence intervals (CIs). The I² value assessed heterogeneity. The risk of bias assessment was conducted with the Joanna Briggs Institute Critical Appraisal Tool. Results: We included 119 articles in the quantitative synthesis and 29 in the IRs calculations. Our results showed that the IR of RAP in adult patients after AP was 5.26 per 100 person-years (CI: 3.99–6.94; I² = 93%), while in children, it was 4.64 per 100 person-years (CI: 2.73–7.87; I² = 88%). We also found that the IR of CP after AP was 1.4 per 100 person-years (CI: 0.9–2; I² = 75%), while after RAP, it increased to 4.3 per 100 person-years (CI: 3.1–6.0; I² = 76%). The risk of bias was moderate in the majority of the included studies. Conclusion: Our results showed that RAP affects many patients with AP. Compared to patients with the first AP episode, RAP leads to a threefold higher IR for developing CP. Trial registration: Our protocol was registered on PROSPERO (CRD42021283252).

Viral infections during pregnancy raise several clinical challenges, including birth defects in the offspring. Thus, this systematic review and meta-analysis aims to prove and highlight the risk of birth defects after first-trimester maternal influenza infection. Our systematic search was performed on 21 November 2022. Studies that reported maternal influenza infection in the first trimester and non-chromosomal congenital abnormalities were considered eligible. We used odds ratios (OR) with 95% confidence intervals (CIs) to measure the effect size. Pooled ORs were calculated with a random effects model. Heterogeneity was measured with I² and Cochran’s Q tests. We found that first-trimester maternal influenza was associated with increased odds of developing any type of birth defects (OR: 1.5, CI: 1.30–1.70). Moreover, newborns were more than twice as likely to be diagnosed with neural tube defects (OR: 2.48, CI: 1.95–3.14) or cleft lip and palate (OR: 2.48, CI: 1.87–3.28). We also found increased odds of developing congenital heart defects (OR: 1.63, CI: 1.27–2.09). In conclusion, influenza increases the odds of non-chromosomal birth defects in the first trimester. The aim of the present study was to estimate the risk of CAs in the offspring of mothers affected by first-trimester influenza infection.

Background: Molar–incisor hypomineralization (MIH) is an enamel defect affecting molars and incisors, often leading to hypersensitivity, enamel breakdown, and increased caries risk. Non-invasive treatments, such as casein phosphopeptide–amorphous calcium phosphate (CPP-ACP) and fluoride varnish, show potential in remineralizing affected enamel and reducing sensitivity, but their efficacy is still debated. This study systematically reviews and analyzes the effectiveness of CPP-ACP and other non-invasive agents in improving remineralization and reducing hypersensitivity in MIH-affected teeth. Methods: A systematic search was conducted on PubMed, Embase, and Central in July 2024, including interventional and observational studies on remineralization and hypersensitivity in pediatric MIH patients (<18 years). A total of 1566 studies were found, with 15 included in the meta-analysis. A random-effects model was applied, including subgroup analysis by lesion severity. Results: CPP-ACP showed no statistically significant advantage over fluoride in remineralization (MD −3.80, 95% CI: −8.57; 0.98), but it significantly reduced hypersensitivity compared to fluoride varnish (MD −2.36, 95% CI: −3.83; −0.89). Although this reduction in hypersensitivity may be clinically relevant, the high heterogeneity (I² = 83%) and wide confidence intervals limit the reliability of these findings. Conclusions: CPP-ACP has a moderate effect in reducing hypersensitivity but does not outperform fluoride in remineralization. Other agents, such as calcium glycerophosphate and silver diamine fluoride, showed mild benefits. The current evidence base is limited and heterogeneous, highlighting the need for high-quality, long-term studies to confirm these findings and guide MIH management.

Background: Splanchnic vein thrombosis is a complication of acute pancreatitis (AP) and is likely often underdiagnosed.Objectives: We aimed to understand the time course and risk factors of splanchnic vein thrombosis in the early phase of AP.Methods: A systematic search was conducted using the PRISMA guidelines (PROSPERO registration CRD42022367578). Inclusion criteria were appropriate imaging techniques in adult AP patients, studies that reported splanchnic vein thrombosis data from the early phase, and reliable information on the timing of imaging in relation to the onset of pancreatitis symptoms or hospital admission. The proportion of patients with thrombosis with 95% confidence intervals (CI) was calculated using random‐effects meta‐analyses, and multiple subgroup analyses were performed.Results: Data from 1951 patients from 14 studies were analyzed. The proportion of patients with splanchnic vein thrombosis within 12 days after symptom onset was 0.13 (CI 0.07–0.23). The occurrence was lowest at 0.06 (CI 0.03–0.1) between 0 and 3 days after symptom onset, and increased fourfold to 0.23 (CI 0.16–0.31) between 3 and 11 days. On hospital admission, the proportion of patients affected was 0.12 (CI 0.02–0.49); it was 0.17 (CI 0.03–0.58) 1–5 days after admission. The prevalence in mild, moderate, and severe AP was 0.15 (CI 0.05–0.36), 0.26 (CI 0.15–0.43), and 0.27 (CI 0.17–0.4), respectively. Alcoholic etiology (0.31, CI 0.13–0.58) and pancreatic necrosis (0.55, CI 0.29–0.78, necrosis above 30%) correlated with increased SVT prevalence.Conclusion: The risk of developing splanchnic vein thrombosis is significant in the early stages of AP and may affect up to a quarter of patients. Alcoholic etiology, pancreatic necrosis, and severity may increase the prevalence of splanchnic vein thrombosis.