Exploration of a new hepatitis a surveillance system in Beijing, China: based on molecular epidemiology

Background The incidence of hepatitis A virus (HAV) infection is low in Beijing, China, but the risk of outbreaks still exists. It is difficult to identify possible sources of infection among sporadic cases based on a routine surveillance system. Therefore, a more effective surveillance system needs to be established. Methods The epidemiological data of hepatitis A were obtained from a routine surveillance system. Patients with HAV confirmed at the local hospitals were asked to complete a questionnaire that included additional case information and possible sources of infection. Serum and fecal specimens were also collected for testing HAV RNA by polymerase chain reaction. In addition, the 321-nucleotide segment of the VP1/2A junction region was sequenced to determine the HAV genotype. Results In 2019, 110 HAV cases were reported in Beijing, with an incidence rate of 0.51/100,000. 61(55.5%) of these patients were male. The greatest proportion of these patients were aged from 30 to 60 years. The rate was lower in suburban and rural areas compared to urban areas. Contaminated food consumption, particularly seafood consumption, was the primary potential source of infection. Among the 16 specimens of confirmed HAV cases that could be sequenced, 93.8% were HAV IA, and 6.3% were HAV IB. In addition, the samples collected from all HAV sequences in this investigation showed 89.4–100% nucleotide homology. Two groups (each with three sporadic cases) showed 100% nucleotide homology. The three sporadic cases in one group had the same possible source of infection: contaminated salad with raw vegetables and seafood. In the other group, the three sporadic cases did not have an epidemiological connection. Conclusions In a low HAV prevalent area, such as in Beijing, incorporating molecular epidemiology into the routine surveillance system could help inform possible clusters of outbreaks and provide support for earlier control of HAV transmission. Nevertheless, increased sampling from detected cases and improved specimen quality are needed to implement such a system.

Superficial Inguinal Lymph Nodes for Screening Dead Pigs for African Swine Fever

African swine fever (ASF) has spread across the globe and has reached closer to North America since being reported in the Dominican Republic and Haiti. As a result, surveillance measures have been heightened and the utility of alternative samples for herd-level monitoring and dead pig sampling have been investigated. Passive surveillance based on the investigation of dead pigs, both domestic and wild, plays a pivotal role in the early detection of an ASF incursion. The World Organization for Animal Health (OIE)-recommended samples for dead pigs are spleen, lymph nodes, bone marrow, lung, tonsil and kidney. However, obtaining these samples requires opening up the carcasses, which is time-consuming, requires skilled labour and often leads to contamination of the premises. As a result, we investigated the suitability of superficial inguinal lymph nodes (SILNs) for surveillance of dead animals. SILNs can be collected in minutes with no to minimum environmental contamination. Here, we demonstrate that the ASF virus (ASFV) genome copy numbers in SILNs highly correlate with those in the spleen and, by sampling SILN, we can detect all pigs that succumb to highly virulent and moderately virulent ASFV strains (100% sensitivity). ASFV was isolated from all positive SILN samples. Thus, sampling SILNs could be useful for routine surveillance of dead pigs on commercial and backyard farms, holding pens and dead on arrival at slaughter houses, as well as during massive die-offs of pigs due to unknown causes.

Impact of The COVID-19 Pandemic on the Malaria Burden in Northern Ghana: Analysis of Routine Surveillance Data

Introduction: The COVID-19 pandemic and its collateral damage severely impact health systems globally and risk to worsen the malaria situation in endemic countries. Malaria is a leading cause of morbidity and mortality in Ghana. This study aims to analyze routine surveillance data to assess possible effects on the malaria burden in the first year of the COVID-19 pandemic in the Northern Region of Ghana. Methods: Monthly routine data from the District Health Information Management System II (DHIMS2) of the Northern Region of Ghana were analyzed. Overall outpatient department visits and malaria incidence rates from the years 2015 to 2019 were compared to the corresponding data of the year 2020. Results: Compared to the corresponding periods of the years 2015 to 2019, overall visits and malaria incidence in pediatric and adult outpatient departments in northern Ghana decreased in March and April 2020, when major movement and social restrictions were implemented in response to the pandemic. Incidence slightly rebounded afterwards in 2020 but stayed below the average of the previous years. Data from inpatient departments showed a similar but more pronounced trend when compared to outpatient departments. In pregnant women, however, malaria incidence in outpatient departments increased after the first COVID-19 wave. Discussion: The findings from this study show that the COVID-19 pandemic affects the malaria burden in health facilities of Ghana, with declines in in- and outpatient rates. Pregnant women may experience reduced access to intermittent preventive malaria treatment and insecticide treated nets, resulting in subsequent higher malaria morbidity. Further data from other African countries, particularly on community-based studies, are needed to fully determine the impact of the pandemic on the malaria situation.

A Quality Improvement Project to Minimize COVID-19 Infections in Patients Receiving Haemodialysis and the Role of Routine Surveillance Using Nose and Throat Swabs for SARS-CoV-2 rRT-PCR and Serum Antibody Testing

<b><i>Background:</i></b> Patients receiving in-centre haemodialysis (ICHD) are highly vulnerable to COVID-19. <b><i>Objective:</i></b> We created a quality improvement (QI) project aimed to eliminate outbreaks of COVID-19 in haemodialysis units and evaluated the utility of surveillance rRT-PCR test and SARS-CoV-2 serum antibodies for prompt identification of patients infected with COVID-19. <b><i>Methods:</i></b> A multifaceted QI programme including a bundle of infection prevention control (IPC) measures was implemented across 5 ICHD units following the first wave of the pandemic in June 2020. Primary outcomes evaluated before and after QI implementation were incidence of outbreaks and severe COVID-19 illness defined as COVID-19-related death or hospitalization. Secondary outcomes included the proportion of patients identified in the pre-symptomatic/asymptomatic phase on surveillance rRT-PCR screening and the incidence and longevity of SARS-CoV-2 antibody response. <b><i>Results:</i></b> Following the implementation of the QI project, there were no further outbreaks. Pre- and post-implementation comparison showed a significant reduction in COVID-19-related mortality and hospitalization (26 vs. 13 events, respectively, <i>p</i> &#x3c; 0.001). Surveillance rRT-PCR screening identified 39 asymptomatic or pre-symptomatic cases out of a total of 59 rRT-PCR-positive patients (39/59, 66%). SARS-CoV-2 antibody levels were detected in 72/74 (97%) rRT-PCR-positive patients. Amongst rRT-PCR-positive patients diagnosed before August 2020, 96% had detectable antibodies until January 2021 (days from the rRT-PCR test to last antibody testing, 245–280). <b><i>Conclusions:</i></b> Systematic implementation of a bundle of IPC measures using QI methodology and surveillance rRT-PCR eliminated outbreaks in HD facilities. Most HD patients mount and sustain antibody response to COVID-19 for over 8 months.

SARS-CoV-2 lineage dynamics in England from September to November 2021: high diversity of Delta sub-lineages and increased transmissibility of AY.4.2

Since the emergence of SARS-CoV-2, evolutionary pressure has driven large increases in the transmissibility of the virus. However, with increasing levels of immunity through vaccination and natural infection the evolutionary pressure will switch towards immune escape. Here we present phylogenetic relationships and lineage dynamics within England (a country with high levels of immunity), as inferred from a random community sample of individuals who provided a self-administered throat and nose swab for rt-PCR testing as part of the REal-time Assessment of Community Transmission-1 (REACT-1) study. From 9 to 27 September 2021 (round 14) and 19 October to 5 November 2021 (round 15), all lineages sequenced within REACT-1 were Delta or a Delta sub-lineage with 44 unique lineages identified. The proportion of the original Delta variant (B.1.617.2) was found to be increasing between September and November 2021, which may reflect an increasing number of sub-lineages which have yet to be identified. The proportion of B.1.617.2 was greatest in London, which was further identified as a region with an increased level of genetic diversity. The Delta sub-lineage AY.4.2 was found to be robustly increasing in proportion, with a reproduction number 15% (8%, 23%) greater than its parent and most prevalent lineage, AY.4. Both AY.4.2 and AY.4 were found to be geographically clustered in September but this was no longer the case by late October/early November, with only the lineage AY.6 exhibiting clustering towards the South of England. Though no difference in the viral load based on cycle threshold (Ct) values was identified, a lower proportion of those infected with AY.4.2 had symptoms for which testing is usually recommend (loss or change of sense of taste, loss or change of sense of smell, new persistent cough, fever), compared to AY.4 (p = 0.026). The evolutionary rate of SARS-CoV-2, as measured by the mutation rate, was found to be slowing down during the study period, with AY.4.2 further found to have a reduced mutation rate relative to AY.4. As SARS-CoV-2 moves towards endemicity and new variants emerge, genomic data obtained from random community samples can augment routine surveillance data without the potential biases introduced due to higher sampling rates of symptomatic individuals.

Optimal vaccine allocation for COVID-19 in the Netherlands: A data-driven prioritization

For the control of COVID-19, vaccination programmes provide a long-term solution. The amount of available vaccines is often limited, and thus it is crucial to determine the allocation strategy. While mathematical modelling approaches have been used to find an optimal distribution of vaccines, there is an excessively large number of possible allocation schemes to be simulated. Here, we propose an algorithm to find a near-optimal allocation scheme given an intervention objective such as minimization of new infections, hospitalizations, or deaths, where multiple vaccines are available. The proposed principle for allocating vaccines is to target subgroups with the largest reduction in the outcome of interest. We use an approximation method to reconstruct the age-specific transmission intensity (the next generation matrix), and express the expected impact of vaccinating each subgroup in terms of the observed incidence of infection and force of infection. The proposed approach is firstly evaluated with a simulated epidemic and then applied to the epidemiological data on COVID-19 in the Netherlands. Our results reveal how the optimal allocation depends on the objective of infection control. In the case of COVID-19, if we wish to minimize deaths, the optimal allocation strategy is not efficient for minimizing other outcomes, such as infections. In simulated epidemics, an allocation strategy optimized for an outcome outperforms other strategies such as the allocation from young to old, from old to young, and at random. Our simulations clarify that the current policy in the Netherlands (i.e., allocation from old to young) was concordant with the allocation scheme that minimizes deaths. The proposed method provides an optimal allocation scheme, given routine surveillance data that reflect ongoing transmissions. This approach to allocation is useful for providing plausible simulation scenarios for complex models, which give a more robust basis to determine intervention strategies.

Schwannoma of the Appendix Orifice

Schwannomas are rare mesenchymal tumors. They are usually diagnosed incidentally during endoscopic or diagnostic imaging for another reason. Malignant transformation is rare. In this case report, we present an incidental schwannoma protruding through the appendiceal orifice diagnosed during endoscopy. A healthy 56-year-old female underwent a surveillance colonoscopy for family history of colorectal cancer. A prominent and edematous appendiceal orifice was noted, and the area was aggressively biopsied. Histopathological assessment revealed a benign schwannoma. Computerized topography was unremarkable. Subsequently, the patient underwent a right hemicolectomy. Patient is scheduled to undergo routine surveillance in three years. Grossly, schwannomas are white, encapsulated, and well-circumscribed lesions that stain strongly positive for S100, GFAP, and CD57. Histologically, schwannomas demonstrate spindle cell proliferation. Several imaging modalities have been utilized in the diagnosis and management of mesenchymal neoplasms. Despite the benign nature of the diagnosis, complete surgical resection with clear margins remains the gold standard management strategy. Our case highlights the presence of a relatively uncommon tumor in an unusual anatomical location.

Comparative Genomics of Clinical and Environmental Isolates of Vibrio spp. of Colombia: Implications of Traits Associated with Virulence and Resistance

There is widespread concern about the increase in cases of human and animal infections caused by pathogenic Vibrio species due to the emergence of epidemic lineages. In Colombia, active surveillance by the National Institute of Health (INS) has confirmed the presence of Vibrio; however, in routine surveillance, these isolates are not genomically characterized. This study focused on the pangenome analysis of six Vibrio species: V. parahaemolyticus, V. vulnificus, V. alginolyticus, V. fluvialis, V. diabolicus and V. furnissii to determine the genetic architectures of potentially virulent and antimicrobial resistance traits. Isolates from environmental and clinical samples were genome sequenced, assembled and annotated. The most important species in public health were further characterized by multilocus sequence typing and phylogenomics. For V. parahaemolyticus, we found the virulent ST3 and ST120 genotypes. For V. vulnificus, we identified isolates belonging to lineages 1 and 2. Virulence gene homologues between species were found even in non-pathogenic species such as V. diabolicus. Annotations related to the mobilome, integrative mobile and conjugative elements and resistance genes were obtained from environmental and clinical isolates. This study contributes genomic information to the intensified surveillance program implemented by the INS to establish potential sources of vibriosis in Colombia.

Assessing real-world vaccine effectiveness against severe forms of SARS-CoV-2 infection from routine surveillance data in Switzerland

Background. In Switzerland, SARS-CoV-2 vaccination campaigns started early 2021. Vaccine coverage reached 65% of the population in December 2021, mostly using mRNA vaccines from Moderna and Pfizer-BioNtech. Simultaneously, the proportion of vaccinated among COVID-19-related hospitalizations and deaths rose, creating some confusion in the general population. We aim to assess vaccine effectiveness against severe forms of SARS-CoV-2 infection using routine surveillance data on the vaccination status of COVID-19-related hospitalizations and deaths and data on vaccination coverage in Switzerland.Methods. We consider all routine surveillance data on COVID-19-related hospitalizations and deaths received at the Swiss Federal Office of Public Health from 1 July 2021 to 1 December 2021. We estimate the relative risk of COVID-19 related hospitalization or death for non-fully vaccinated compared to fully vaccinated individuals, adjusted for the dynamics of vaccination coverage over time, by age and location. We stratify the analysis by age group and by calendar month. We assess variations in the relative risk of hospitalization associated with the time since vaccination.Results. We include a total of 5,948 COVID-19-related hospitalizations of which 1,245 (21%) were fully vaccinated, and a total of 739 deaths of which 259 (35%) were fully vaccinated. We find that the relative risk of COVID-19 related hospitalization is 12.5 (95%CI: 11.7 to 13.4) times higher for non-fully vaccinated than for fully vaccinated individuals. This translates into a vaccine effectiveness against hospitalization of 92.0% (95%CI: 91.4 to 92.5%). Vaccine effectiveness against death is estimated to 90.3% (95%CI: 88.6 to 91.8%). Effectiveness appears comparatively lower in age groups over 70 and during the months of October and November 2021. We also find evidence of a decrease in vaccine effectiveness against hospitalization for individuals vaccinated for 25 weeks or more, but this decrease only appears in age groups below 70.Conclusions. The observed proportions of vaccinated among COVD-19-related hospitalizations and deaths in Switzerland are compatible with a high effectiveness of mRNA vaccines from Moderna and Pfizer-BioNtech against hospitalization and death in all age groups. Effectiveness appears comparatively lower in older age groups, suggesting the importance of booster vaccinations. We find inconclusive evidence that vaccine effectiveness is waning over time. Repeated analyses will be able to better assess waning and the effect of boosters.

P-P48 Clinical Benefit of Surveillance after Resection of Pancreatic Ductal Adenocarcinoma: A Systematic Review and Meta-Analysis

Background The clinical benefit and acceptability to patients of routine surveillance after resection of pancreatic ductal adenocarcinoma (PDAC) remains unclear. Furthermore, expert guidelines around the world offer conflicting recommendations. This study is a systematic review of evidence for surveillance programs. Methods A systematic review of studies evaluating different surveillance methods was undertaken. Meta-analyses were performed for those studies reporting rates of asymptomatic recurrence, treatment of recurrence and overall survival, according to different surveillance methods. Results There were ten studies included in the literature review. Five studies were appropriate for meta-analysis (1,596 patients). If enrolled in an active surveillance program, patients were more likely to have recurrence detected at an asymptomatic stage (Pooled Rate: 49.3% vs. 19.1%, p = 0.043). In terms of clinical outcomes, patients with asymptomatic recurrence were more likely to receive treatment for recurrence (Odds Ratio 3.49; 95% CI: 1.73-7.07; p &lt; 0.001) and had longer overall survival (Mean Difference: 9.5 months; 95% CI: 4.1-14.8; p &lt; 0.001) than those with symptoms at time of recurrence. Conclusions From this systematic review and meta-analysis of early data it appears that routine surveillance after surgery for PDAC detects more patients at the asymptomatic stage. Data from these non-randomised trials also suggest that treatment rates and survival may be superior in patients were recurrence is detected when asymptomatic. As such, these data suggest that routine surveillance may improve patient outcomes, however an appropriately conducted trial would be required to address concerns that various sources of bias may be affecting these results.