Immunogenicity and safety of heterologous versus homologous prime-boost schedules with inactivated and adenoviral vectored SARS-CoV-2 vaccines - A prospective multi-center study

Background

During the peak of Coronavirus disease (COVID-19) pandemic in Thailand when the emergence of delta variant reduced the efficacy of inactivated vaccine, Thailand had abundance of inactivated vaccine but mRNA vaccine was not available and the supply of adenoviral-vectored vaccine was limited. The heterologous vaccination using CoronaVac and ChAdOx1-nCoV-19 vaccines was applied. We aim to compare the immunogenicity of immune response of primary vaccination with homologous ChAdOx1 nCoV-19 and heterologous vaccination with CoronaVac and ChAdOx1 nCoV-19.

Methods

A total of 430 adults, scheduled to receive ChAdOx1-nCoV-19 as their second dose of primary COVID-19 vaccination, were enrolled. Participants were classified into two groups based on the first dose vaccine as CoronaVac (heterologous group) or ChAdOx1 nCoV-19 (homologous group). The primary outcome was antibodies to the SARS-CoV-2 spike protein receptor binding domain (anti-RBD) titres at 28 days after the second dose of vaccination. Secondary outcomes were anti-RBD titres at 90 days, surrogate viral neutralizing test (sVNT) at 28 and 90 days, and adverse events.

Findings

In 358 participants with correct vaccine interval, the anti-RBD geometric mean titre ratio for the heterologous versus homologous group was 0.55 (95%CI; 0.44-0.067); p < 0.001 at day 28, and 0.80 (95%CI; 0.65-1.00); P = 0.05 at day 90. Median sVNT neutralizing activity was not significantly different in the heterologous versus homologous group at 28 days (93.5 vs 92.7 %); p = 0.13, but significantly higher in the heterologous group at day 90 (82.9 vs 76.4 %); p = 0.01.

Interpretation

The homologous vaccination resulted in higher anti-RBD titres at 28 days after vaccination, but titres in the homologous group showed more rapid decline at 90 days. In the sVNT assay, median neutralization was similar at 28 days, but was longer-lasting and higher in the heterologous group at 90 days.

Funding

This research received funding from the Royal College of Physicians of Thailand special grant 2021 for research initiative during COVID-19 pandemic.

Spot Hydrogen Breath Test for Predicting Response to Low Fermentable Oligo-, Di-, Mono-saccharides, and Polyols Dietary Advice in Patients With Bloating

Background/Aims

An increase in postprandial intestinal gas plays a role in bloating symptoms. We aim to study the utility of spot breath hydrogen (H2) level in predicting the response to a low fermentable oligo-, di-, mono-saccharides, and polyols (FODMAPs) diet.

Methods

Patients with functional gastrointestinal disorders diagnosed by Rome IV criteria with bothersome bloating for > 6 months were prospectively enrolled. Patients completed 7-day food diaries and collected a breath sample 2 hours after their usual lunch at baseline and 4 weeks after low FODMAPs dietary advice by a dietitian. The responder was defined as an improvement of ≥ 30% bloating scores in the fourth week.

Results

Thirty-eight patients (32 female, 52.6 ± 13.8 years; 22 irritable bowel syndrome) completed the study. Twenty-one patients (55%) were classified as responders. Baseline global gastrointestinal symptoms, bloating, abdominal pain scores, and numbers of high FODMAPs items were similar between responders and non-responders. Both groups significantly decreased high FODMAPs items intake with similar numbers at the follow-up. The area under the curve for predicting low FODMAPs responsiveness using baseline H2 levels was 0.692 (95%CI, 0.51-0.86; P < 0.05), with the best cutoff at 8 parts per million (sensitivity 66.7%, specificity 82.4%). 66% of responders had baseline H2 level > 8 parts per million vs 17% of non-responders (P < 0.05). The baseline spot hydrogen level in responders was 9.5 (3.3-17.3) vs 4.5 (3.3-6.3) in non-responders (P < 0.05).

Conclusions

A higher baseline breath hydrogen level was associated with bloating improvement after low FODMAPs dietary advice. A spot breath test after lunch, a simple point-of-care test, is possibly helpful in managing patients with bloating.

Artificial intelligence assists operators in real-time detection of focal liver lesions during ultrasound: A randomized controlled study

PURPOSE

Detection of hepatocellular carcinoma (HCC) is crucial during surveillance by ultrasound. We previously developed an artificial intelligence (AI) system based on convolutional neural network for detection of focal liver lesions (FLLs) in ultrasound. The primary aim of this study was to evaluate whether the AI system can assist non-expert operators to detect FLLs in real-time, during ultrasound examinations.

METHOD

This single-center prospective randomized controlled study evaluated the AI system in assisting non-expert and expert operators. Patients with and without FLLs were enrolled and had ultrasound performed twice, with and without AI assistance. McNemar's test was used to compare paired FLL detection rates and false positives between groups with and without AI assistance.

RESULTS

260 patients with 271 FLLs and 244 patients with 240 FLLs were enrolled into the groups of non-expert and expert operators, respectively. In non-experts, FLL detection rate in the AI assistance group was significantly higher than the no AI assistance group (36.9 % vs 21.4 %, p < 0.001). In experts, FLL detection rates were not significantly different between the groups with and without AI assistance (66.7 % vs 63.3 %, p = 0.32). False positive detection rates in the groups with and without AI assistance were not significantly different in both non-experts (14.2 % vs 9.2 %, p = 0.08) and experts (8.6 % vs 9.0 %, p = 0.85).

CONCLUSIONS

The AI system resulted in significant increase in detection of FLLs during ultrasound examinations by non-experts. Our findings may support future use of the AI system in resource-limited settings where ultrasound examinations are performed by non-experts. The study protocol was registered under the Thai Clinical Trial Registry (TCTR20201230003), which is part of the WHO ICTRP Registry Network. The registry can be accessed via the following URL: https://trialsearch.who.int/Trial2.aspx?TrialID=TCTR20201230003.

Linked color imaging, mucosal exposure device, their combination, and standard colonoscopy for adenoma detection: a randomized trial

BACKGROUND AND AIMS

By different mechanisms, image-enhancement techniques (linked color imaging [LCI]) and mucosal exposure devices (Endocuff-assisted colonoscopy [EAC]) can improve the adenoma detection rate (ADR) during screening colonoscopy. The impact of the combination of the 2 techniques has never been studied. This study aimed to compare the ADR between the combination of LCI and EAC (LCI+EAC), LCI alone, EAC alone, and standard high-definition (HD) colonoscopy.

METHODS

This prospective randomized controlled trial included participants who underwent screening colonoscopy. Participants were randomized to LCI+EAC, LCI, EAC, and standard HD colonoscopy. All colonoscopies were performed by endoscopists with a recorded ADR ≥35%. The primary outcome was the ADR. Secondary outcomes were proximal ADR (pADR) and the mean number of adenomas per colonoscopy (APC).

RESULTS

One thousand participants were included in the study. The LCI+EAC group provided the highest ADR and pADR. The ADRs in the LCI+EAC, LCI, EAC, and standard HD colonoscopy groups were 57.2%, 52.8%, 51.6%, and 47.6%, respectively, with pADRs of 38.4%, 34.8%, 33.6%, and 28.0%, respectively. The mean numbers of APC were 1.28, 1.20, 1.16, and .89, respectively. After a multiple comparison adjustment, a significant difference in pADR was only observed between the LCI+EAC and standard HD colonoscopy groups (difference, 10.3 percentage points; 95% confidence interval, .02%-17.4%; P = .05). The incidence rate ratios of the adenoma numbers were significantly higher in the LCI+EAC (1.43), LCI (1.34), and EAC (1.30) groups relative to the standard HD colonoscopy group (.89) (P < .009 for all comparisons).

CONCLUSIONS

The combination of LCI and EAC can significantly improve the detection of pADR and APC but not ADR by high-ADR performers. (Clinical trial registration number: TCTR20190319001.).

Video-assisted liver ultrasound training for non-radiologists: protocol and preliminary results

BACKGROUND

Ultrasound (US) is increasingly used as a bedside diagnostic tool, with training courses for non-radiologists being developed. However, the training time constraint is an important barrier for non-radiologists. We therefore created a short self-learning course for liver-US for non-radiologists.

AIM

Assess the participants' ability in identifying the organ structures during a liver-US.

METHOD

A short video-lecture on liver-US training and a portable guidebook for image acquisition were developed. Eighteen non-radiologist physicians studied the course and attended hands-on liver-US examinations to capture the assigned images and label the acquired organ/structures, which were evaluated by an expert radiologist.

RESULT

130 liver-US examinations were performed, 44 (33.8%) was cirrhosis. The overall of mean image acquisition score was 84.5 ± 9.7%. The mean score of the 1st examination was 75.2 ± 16.4. The mean score was >80% since the 2nd examination. The score was significant lower in cirrhotic cases as compared to non-cirrhotic cases (78.8 ± 17.3 vs. 88.3 ± 14.4, p = 0.001). The participants' year of study and experience in previous US training did not affect the image acquisition score.

CONCLUSION

The liver-US training course in a short video format with a portable guidebook is effective and relatively low time-consuming for teaching non-radiologists to perform bedside liver-US.

ERCP plus endoscopic ultrasound-guided biliary drainage versus percutaneous transhepatic biliary drainage for malignant hilar biliary obstruction: a multicenter observational open-label study

BACKGROUND

Endoscopic retrograde cholangiopancreatography (ERCP) may not provide complete biliary drainage in patients with Bismuth III/IV malignant hilar biliary obstruction (MHBO). Complete biliary drainage is accomplished by adding percutaneous transhepatic biliary drainage (PTBD). We prospectively compared recurrent biliary obstruction (RBO) rates between combined ERCP and endoscopic ultrasound-guided biliary drainage (EUS-BD) vs. bilateral PTBD.

METHODS

Patients with MHBO undergoing endoscopic procedures (group A) were compared with those undergoing bilateral PTBD (group B). The primary outcome was the 3-month RBO rate.

RESULTS

36 patients were recruited into groups A (n = 19) and B (n = 17). Rates of technical and clinical success, and complications of group A vs. B were 84.2 % (16/19) vs. 100 % (17/17; P = 0.23), 78.9 % (15/19) vs. 76.5 % (13/17; P > 0.99), and 26.3 % (5/19) vs. 35.3 % (6/17; P = 0.56), respectively. Within 3 and 6 months, RBO rates of group A vs. group B were 26.7 % (4/15) vs. 88.2 % (15/17; P  = 0.001) and 22.2 % (2/9) vs. 100 % (9/9; P = 0.002), respectively. At 3 months, median number of biliary reinterventions in group A was significantly lower than in group B (0 [interquartile range] 0-1 vs. 1 [1-2.5]), respectively (P < 0.001). Median time to development of RBO was longer in group A than in group B (92 [56-217] vs. 40 [13.5-57.8] days, respectively; P  =  0.06).

CONCLUSIONS

Combined ERCP and EUS procedures provided significantly lower RBO rates at 3 and 6 months vs. bilateral PTBD, with similar complication rates and no significant mortality difference.

Overweight as an Additional Risk Factor for Colorectal Neoplasia in Lean Population

Background:

Overweight in Thailand is not as common as in Western countries. We sought to evaluate overweight as the additional risk factor that can increase the prediction of colorectal neoplasia (CRN) detection in Thais apart from the Asia-Pacific Colorectal Screening (APCS) score.

Methods:

We prospectively enrolled asymptomatic 338 subjects who underwent screening colonoscopy between November 2016 and September 2017. All risk factors according to APCS, BMI and the presence of metabolic syndrome were collected. Overweight was defined as BMI ≥23 kg/m². By APCS score, subjects were categorized into 1) high-risk and 2) average-risk. Using the combination of APCS score and overweight, subjects were stratified into 4 groups; high-risk with overweight (G1), average-risk with overweight (G2), high-risk with normal weight (G3) average-risk and with normal weight (G4). Logistic regression analysis was used to estimate the risk of detecting CRN.

Results:

The prevalence of CRN in the high-risk subjects was higher than that of in the average-risk subjects (49%vs.32%; OR, 2.00; 95%CI, 1.17-3.41). After adjustment for APCS risk factors and metabolic syndrome, overweight significantly increased the risk of detecting CRN (OR, 2.52; 95%CI, 1.57-4.05). Among the 4 groups, the detection rates of CRN were significantly different (G1=64%, G2=40%, G3=32% and G4=21%, p<0.01). The relative risk of detecting CRN increased when G1 (OR 6.49; 95%CI, 2.87-14.67), and G2 (2.42; 1.39-4.21) were compared with G4.

Conclusions:

In addition to the APCS score, overweight is an independent risk factor for detecting CRN. In Thai population, combining overweight and APCS score may be useful to improve the prediction for CRN.