Protection against SARS-CoV-2 after Covid-19 Vaccination and Previous Infection.

BACKGROUND: The duration and effectiveness of immunity from infection with and vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are relevant to pandemic policy interventions, including the timing of vaccine boosters. METHODS: We investigated the duration and effectiveness of immunity in a prospective cohort of asymptomatic health care workers in the United Kingdom who underwent routine polymerase-chain-reaction (PCR) testing. Vaccine effectiveness (≤10 months after the first dose of vaccine) and infection-acquired immunity were assessed by comparing the time to PCR-confirmed infection in vaccinated persons with that in unvaccinated persons, stratified according to previous infection status. We used a Cox regression model with adjustment for previous SARS-CoV-2 infection status, vaccine type and dosing interval, demographic characteristics, and workplace exposure to SARS-CoV-2. RESULTS: Of 35,768 participants, 27% (9488) had a previous SARS-CoV-2 infection. Vaccine coverage was high: 95% of the participants had received two doses (78% had received BNT162b2 vaccine [Pfizer-BioNTech] with a long interval between doses, 9% BNT162b2 vaccine with a short interval between doses, and 8% ChAdOx1 nCoV-19 vaccine [AstraZeneca]). Between December 7, 2020, and September 21, 2021, a total of 2747 primary infections and 210 reinfections were observed. Among previously uninfected participants who received long-interval BNT162b2 vaccine, adjusted vaccine effectiveness decreased from 85% (95% confidence interval [CI], 72 to 92) 14 to 73 days after the second dose to 51% (95% CI, 22 to 69) at a median of 201 days (interquartile range, 197 to 205) after the second dose; this effectiveness did not differ significantly between the long-interval and short-interval BNT162b2 vaccine recipients. At 14 to 73 days after the second dose, adjusted vaccine effectiveness among ChAdOx1 nCoV-19 vaccine recipients was 58% (95% CI, 23 to 77) - considerably lower than that among BNT162b2 vaccine recipients. Infection-acquired immunity waned after 1 year in unvaccinated participants but remained consistently higher than 90% in those who were subsequently vaccinated, even in persons infected more than 18 months previously. CONCLUSIONS: Two doses of BNT162b2 vaccine were associated with high short-term protection against SARS-CoV-2 infection; this protection waned considerably after 6 months. Infection-acquired immunity boosted with vaccination remained high more than 1 year after infection. (Funded by the U.K. Health Security Agency and others; ISRCTN Registry number, ISRCTN11041050.).

Randomized controlled trial of hemostatic powder versus endoscopic clipping for non-variceal upper gastrointestinal bleeding.

BACKGROUND AND AIMS: Despite advances in pharmacological and endoscopic management of non-variceal upper gastrointestinal bleeding (NVUGIB), mortality is still relevant. TC-325 (Hemospray-Cook Medical) is a mineral powder with adsorptive properties, designed for endoscopic hemostasis. There are still no comparative trials studying this new hemostatic modality. The objective of this research was to compare the use of TC-325 (associated with epinephrine injection) with the combined technique of endoscopic clipping and epinephrine injection for the treatment of patients with NVUGIB. METHODS: We conducted a pilot randomized controlled trial with patients that presented NVUGIB with an actively bleeding lesion at the endoscopic evaluation. Patients were randomized either to the Hemospray or Hemoclip group. The randomization list was generated by a computer program and remained unknown throughout the entire trial. All patients underwent second-look endoscopy. RESULTS: Thirty-nine patients were enrolled. Peptic ulcer was the most frequent etiology. Primary hemostasis was achieved in all Hemospray cases and in 90% of Hemoclip group (p = 0.487). Five patients in Hemospray group underwent an additional hemostatic procedure during second-look endoscopy, while no patient in the Hemoclip group needed it (p = 0.04). Rebleeding, emergency surgery and mortality rates were similar in both groups. No toxicity, allergy events, or gastrointestinal obstruction signs were observed in Hemospray group. CONCLUSIONS: TC-325 presents similar hemostatic results when compared with conventional dual therapy for patients with NVUGIB. Hemospray's excellent primary hemostasis rate certifies it as a valuable tool in arduous situations of severe bleeding or difficult location site.

Antibody correlates of protection from SARS-CoV-2 reinfection prior to vaccination: A nested case-control within the SIREN study.

OBJECTIVES: To investigate serological differences between SARS-CoV-2 reinfection cases and contemporary controls, to identify antibody correlates of protection against reinfection. METHODS: We performed a case-control study, comparing reinfection cases with singly infected individuals pre-vaccination, matched by gender, age, region and timing of first infection. Serum samples were tested for anti-SARS-CoV-2 spike (anti-S), anti-SARS-CoV-2 nucleocapsid (anti-N), live virus microneutralisation (LV-N) and pseudovirus microneutralisation (PV-N). Results were analysed using fixed effect linear regression and fitted into conditional logistic regression models. RESULTS: We identified 23 cases and 92 controls. First infections occurred before November 2020; reinfections occurred before February 2021, pre-vaccination. Anti-S levels, LV-N and PV-N titres were significantly lower among cases; no difference was found for anti-N levels. Increasing anti-S levels were associated with reduced risk of reinfection (OR 0·63, CI 0·47-0·85), but no association for anti-N levels (OR 0·88, CI 0·73-1·05). Titres >40 were correlated with protection against reinfection for LV-N Wuhan (OR 0·02, CI 0·001-0·31) and LV-N Alpha (OR 0·07, CI 0·009-0·62). For PV-N, titres >100 were associated with protection against Wuhan (OR 0·14, CI 0·03-0·64) and Alpha (0·06, CI 0·008-0·40). CONCLUSIONS: Before vaccination, protection against SARS-CoV-2 reinfection was directly correlated with anti-S levels, PV-N and LV-N titres, but not with anti-N levels. Detectable LV-N titres were sufficient for protection, whilst PV-N titres >100 were required for a protective effect. TRIAL REGISTRATION NUMBER: ISRCTN11041050.

BEST POLYPECTOMY TECHNIQUE FOR SMALL AND DIMINUTIVE COLORECTAL POLYPS: A SYSTEMATIC REVIEW AND META-ANALYSIS.

BACKGROUND: Polypectomy of colorectal polyps is the mainstay of colorectal cancer prevention. Identification of the best polypectomy technique is imperative. OBJECTIVE: This review aims at comparing efficacy of nine different resection methods for small colorectal polyps (<10 mm). METHODS: We searched and selected only randomized controlled trials. Primary outcome was complete resection rates of small polyps by histological eradication. Secondary outcomes were: adverse events, retrieval tissue failures rates and duration of procedure. RESULTS: Eighteen trials including 3215 patients and 5223 polyps were analysed. Overall, cold polypectomy had a significantly shorter time of procedure than hot polypectomy (RD -5.92, 95%CI -9.90 to -1.94, P<0.05), with no statistical difference on complete histological eradication (RD 0.08, 95%CI -0.03 to 0.19, P>0.05). Regarding cold polypectomy techniques, cold snare was found superior to cold forceps on complete and en-bloc resection rates and less time consuming. When comparing endoscopic mucosal resection (EMR) with hot-snare and cold-snare, the latter showed no-inferiority on histological eradication, adverse events or retrieval tissue failure rates. CONCLUSION: Cold polypectomy is the best technique for resection of small colorectal polyps. Among cold methods, dedicated cold snare was found superior on histological eradication. Cold snare endoscopic mucosal resection might be considered an option for polyps from 5 to 9 mm.

Revisão sistemática e meta-análise sobre técnicas de polipectomia de pólipos colorretais pequenos e diminutos / Best polypectomy technique for small and diminutive colorectal polyps: a systematic review and meta-analysis

ABSTRACT BACKGROUND: Polypectomy of colorectal polyps is the mainstay of colorectal cancer prevention. Identification of the best polypectomy technique is imperative. OBJECTIVE: This review aims at comparing efficacy of nine different resection methods for small colorectal polyps (<10 mm). METHODS: We searched and selected only randomized controlled trials. Primary outcome was complete resection rates of small polyps by histological eradication. Secondary outcomes were: adverse events, retrieval tissue failures rates and duration of procedure. RESULTS: Eighteen trials including 3215 patients and 5223 polyps were analysed. Overall, cold polypectomy had a significantly shorter time of procedure than hot polypectomy (RD -5.92, 95%CI -9.90 to -1.94, P<0.05), with no statistical difference on complete histological eradication (RD 0.08, 95%CI -0.03 to 0.19, P>0.05). Regarding cold polypectomy techniques, cold snare was found superior to cold forceps on complete and en-bloc resection rates and less time consuming. When comparing endoscopic mucosal resection (EMR) with hot-snare and cold-snare, the latter showed no-inferiority on histological eradication, adverse events or retrieval tissue failure rates. CONCLUSION: Cold polypectomy is the best technique for resection of small colorectal polyps. Among cold methods, dedicated cold snare was found superior on histological eradication. Cold snare endoscopic mucosal resection might be considered an option for polyps from 5 to 9 mm.

RESUMO CONTEXTO: A polipectomia de pólipos colorretais é a base da prevenção do câncer colorretal. A identificação da melhor técnica de polipectomia é imperativa. OBJETIVO: Esta revisão tem como objetivo comparar a eficácia de nove diferentes métodos de ressecção para pólipos colorretais pequenos (<10 mm). MÉTODOS: Pesquisamos e selecionamos apenas ensaios clínicos randomizados. O desfecho primário foi taxas de ressecção completa de pólipos pequenos por confirmação histológica. Os desfechos secundários foram: eventos adversos, taxas de falha de recuperação do espécime e duração do procedimento. RESULTADOS: Dezoito estudos, incluindo 3215 pacientes e 5223 pólipos foram analisados. No geral, a polipectomia a frio teve um tempo de procedimento significativamente menor do que a polipectomia a quente (RD -5,92; IC 95% -9,90 a -1,94; P<0,05), sem diferença estatística na erradicação histológica (RD 0,08; IC 95% -0,03 a 0,19; P>0,05). Em relação às técnicas de polipectomia a frio, a alça fria foi considerada superior ao uso de pinça fria nas taxas de ressecção completa e em bloco, além de um menor tempo de procedimento. Ao comparar a ressecção endoscópica da mucosa utilizando alça quente ou alça fria, esta última mostrou não-inferioridade na erradicação histológica, eventos adversos ou taxas de falha do tecido de recuperação. CONCLUSÃO: A polipectomia a frio mostrou ser a melhor técnica para ressecção de pequenos pólipos colorretais. Entre os métodos frios, a alça fria dedicada foi considerada superior na erradicação histológica. ressecção endoscópica da mucosa com alça fria pode ser considerado uma opção para pólipos de 5 a 9 mm.