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SUMMARY Our gastrointestinal tract is colonized by trillions of microbes. There is growing recognition that commensal bacteria can promote the development of colorectal adenomas and cancer. For example, bacterial plaques are strongly associated with adenomas in familial adenomatous polyposis (Science 2018;359:592-597), and fusobacterium is associated with colorectal cancer liver metastasis.(Science 2017;358:1443-1448)

Background and aims Ampullary adenomas (AAs), common in familial adenomatous polyposis (FAP), are precursors to ampullary carcinoma. We assessed the natural history of AA and factors associated with clinically significant progression (CSP). Methods Consecutive FAP patients with AAs and ≥2 esophagogastroduodenoscopies (EGD) were identified from a hereditary gastrointestinal cancer registry. We assessed the incidence of CSP (increase in size to >10 mm, and/or development of advanced histology) of AA. Clinical, endoscopic, and pathologic features between patients with CSP and nonprogressors were compared. Results One hundred forty-three patients with AAs were included. Over a median follow-up of 7.8 years (interquartile range: 4.3 to 11.1 years), 41 (28.6%) patients developed CSP for an incidence of 35 per 1000 patient-years. Of 143 patients, 22 (15.6%) progressed to AA >10 mm, 12 (8.5%) progressed to advanced histology, and 7 (4.9%) progressed both in size and histology. Two (1.4%) patients developed ampullary cancer. Male gender, abnormal appearance of papilla at initial AA detection, prior cholecystectomy, and personal history of extracolonic malignancy were associated with CSP. Neither Spigelman stage nor Adenomatous Polyposis Coli gene pathogenic variants were associated with CSP. Intervention specifically for AA and not duodenal polyposis was performed in 24% patients with AAs, including endoscopic papillectomy in 23 patients and duodenectomy in 3 at median observation of 8.2 years. Conclusions Majority of FAP patients with AAs did not experience CSP or require resection over 8 years of surveillance. Ampullary cancer was rare. Male gender, abnormal appearance of the papilla at AA detection, cholecystectomy and history of extracolonic malignancy are associated with CSP. Our findings favor endoscopic surveillance of AAs over expedited resection for most patients with FAP.

BackgroundMany studies report the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies. We aimed to synthesize seroprevalence data to better estimate the level and distribution of SARS-CoV-2 infection, identify high-risk groups, and inform public health decision making.MethodsIn this systematic review and meta-analysis, we searched publication databases, preprint servers, and grey literature sources for seroepidemiological study reports, from January 1, 2020 to December 31, 2020. We included studies that reported a sample size, study date, location, and seroprevalence estimate. We corrected estimates for imperfect test accuracy with Bayesian measurement error models, conducted meta-analysis to identify demographic differences in the prevalence of SARS-CoV-2 antibodies, and meta-regression to identify study-level factors associated with seroprevalence. We compared region-specific seroprevalence data to confirmed cumulative incidence. PROSPERO: CRD42020183634.ResultsWe identified 968 seroprevalence studies including 9.3 million participants in 74 countries. There were 472 studies (49%) at low or moderate risk of bias. Seroprevalence was low in the general population (median 4.5%, IQR 2.4–8.4%); however, it varied widely in specific populations from low (0.6% perinatal) to high (59% persons in assisted living and long-term care facilities). Median seroprevalence also varied by Global Burden of Disease region, from 0.6% in Southeast Asia, East Asia and Oceania to 19.5% in Sub-Saharan Africa (pDiscussionMost of the population remains susceptible to SARS-CoV-2 infection. Public health measures must be improved to protect disproportionately affected groups, including racial and ethnic minorities, until vaccine-derived herd immunity is achieved. Improvements in serosurvey design and reporting are needed for ongoing monitoring of infection prevalence and the pandemic response.

BackgroundMany studies report the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies. We aimed to synthesize seroprevalence data to better estimate the level and distribution of SARS-CoV-2 infection, identify high-risk groups, and inform public health decision making.MethodsIn this systematic review and meta-analysis, we searched publication databases, preprint servers, and grey literature sources for seroepidemiological study reports, from January 1, 2020 to December 31, 2020. We included studies that reported a sample size, study date, location, and seroprevalence estimate. We corrected estimates for imperfect test accuracy with Bayesian measurement error models, conducted meta-analysis to identify demographic differences in the prevalence of SARS-CoV-2 antibodies, and meta-regression to identify study-level factors associated with seroprevalence. We compared region-specific seroprevalence data to confirmed cumulative incidence. PROSPERO: CRD42020183634.ResultsWe identified 968 seroprevalence studies including 9.3 million participants in 74 countries. There were 472 studies (49%) at low or moderate risk of bias. Seroprevalence was low in the general population (median 4.5%, IQR 2.4-8.4%); however, it varied widely in specific populations from low (0.6% perinatal) to high (59% persons in assisted living and long-term care facilities). Median seroprevalence also varied by Global Burden of Disease region, from 0.6 % in Southeast Asia, East Asia and Oceania to 19.5% in Sub-Saharan Africa (pDiscussionMost of the population remains susceptible to SARS-CoV-2 infection. Public health measures must be improved to protect disproportionately affected groups, including racial and ethnic minorities, until vaccine-derived herd immunity is achieved. Improvements in serosurvey design and reporting are needed for ongoing monitoring of infection prevalence and the pandemic response.FundingPublic Health Agency of Canada through the COVID-19 Immunity Task Force.

Endoscopic delivery of a low-cost OCT system has the potential to promote new diagnostic assessment of the lower gastrointestinal tract. We review current technologies and applications to highlight the direction of OCT in this region.