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Monkeypox is a zoonosis endemic to West and Central Africa; human cases were first reported in 1970 (1). An outbreak ongoing in Nigeria since 2017 is the largest documented (2). [...]

Human adenoviruses (HAdVs) are classified into >50 types and are associated with clinical manifestations that include respiratory, gastrointestinal, ocular, genitourinary, and neurologic disease (1). HAdV infections have been estimated to [...]

Seasonal influenza causes a substantial burden of illness worldwide. Infections can lead to severe illness that requires hospital care and can occasionally lead to death. Several studies have documented influenza-associated [...]

Background: Respiratory syncytial virus (RSV) infections are one of the leading causes of lower respiratory tract infections and have a major burden on society. For prevention and control to be deployed effectively, an improved understanding of the seasonality of RSV is necessary. Objectives: The main objective of this study was to contribute to a better understanding of RSV seasonality by examining the GERi multi‐country surveillance dataset. Methods: RSV seasons were included in the analysis if they contained ≥100 cases. Seasonality was determined using the "average annual percentage" method. Analyses were performed at a subnational level for the United States and Brazil. Results: We included 601 425 RSV cases from 12 countries. Most temperate countries experienced RSV epidemics in the winter, with a median duration of 10–21 weeks. Not all epidemics fit this pattern in a consistent manner, with some occurring later or in an irregular manner. More variation in timing was observed in (sub)tropical countries, and we found substantial differences in seasonality at a subnational level. No association was found between the timing of the epidemic and the dominant RSV subtype. Conclusions: Our findings suggest that geographical location or climatic characteristics cannot be used as a definitive predictor for the timing of RSV epidemics and highlight the need for (sub)national data collection and analysis. [ABSTRACT FROM AUTHOR]

Objective: To describe the characteristics of healthcare workers (HCWs) infected with COVID‐19 and to examine their sources of exposure. Methods: A descriptive cross‐sectional study using data extracted from the centralized disease notification system comprising individuals confirmed with COVID‐19 in Singapore between 23 January and 17 April 2020. Occupation of HCWs was categorized into six categories. Their job nature was classified into "frontline" or "back‐end" based on the frequency of direct patient contact, and source of exposure was classified as family/household, social interaction or workplace. Chi‐square and median tests were used to identify differences between categorical groups and sample medians, respectively. Results: A total of 88 (1.7%) HCWs were identified from 5,050 cases. Their median age was 35 years. Chinese and Indians constituted 42.0% and 31.8%, respectively, and 43.2% were foreigners. The majority (63.6%) was serving at frontlines handling patient‐facing duties, 15.9% were doctors, 11.4% were nurses and 44.3% were ancillary staff. About 81.8% acquired the infection locally, of which 40.3% did not have a clearly identifiable source of exposure. Exposure from the family/household was most common (27.8%), followed by workplace (16.7%) and social interaction (15.3%). All HCWs were discharged well with no mortality; three (3.4%) were ever admitted to intensive care unit and required increased care. Conclusion: Healthcare workers accounted for a small proportion of COVID‐19 cases in Singapore with favourable outcomes. The possibility of transmission resulting from family/household exposure and social interactions highlights the need to maintain strict vigilance and precautionary measures at all times beyond the workplace. [ABSTRACT FROM AUTHOR]

Background: Respiratory syncytial virus (RSV) is an important respiratory pathogen that affects people of all ages. Objectives: We examined the patterns of RSV circulation in 2014‐2018, and investigated their age‐specific differences in tropical Singapore. Methods: Nasopharyngeal and/or throat swabs were taken from outpatient attendees for the national influenza virological surveillance among those who presented with acute respiratory illness in the community. Specimens tested negative for influenza were then tested for RSV and other respiratory pathogens. Results: Among 8436 influenza‐negative specimens tested during the five‐year period, 5.8% (95% confidence interval 5.3%‐6.3%) were positive for RSV. The peak of RSV activity occurred around middle of the year. The age‐specific proportion of RSV detections showed a reverse J‐shaped pattern; RSV positivity was the highest in young children ≤2 years of age (10.9%), followed by those aged 3‐5 years (6.4%) and persons aged ≥65 years (5.3%), while the nadir was observed in the age group of 15‐24 years (1.2%). RSV type A was predominantly circulating in children ≤5 years of age from 2014 to 2015 and 2017, whereas in 2016, they were more affected by type B. Conclusion: Respiratory syncytial virus was more frequently detected among the two age groups that have been recommended for influenza vaccination; persons ≥65 years of age and children 6 months to <5 years of age. Characterisation of RSV activity in the community helps to better inform public health policies for effective prevention and control interventions. [ABSTRACT FROM AUTHOR]

Background: We report our experience in evaluating the severity of local influenza epidemics using the World Health Organization Pandemic Influenza Severity Assessment framework. Methods: We assessed the severity of influenza by monitoring indicators of influenza transmissibility, seriousness of disease and impact on healthcare resource utilisation. Indicators were described by various parameters collected weekly from eight government hospitals, 20 government and 30 private primary care clinics, and the national public health laboratory. Transmissibility and seriousness of disease indicators were each represented by multiple parameters, and alert thresholds were set at the 70th and 90th percentile of a parameter's past 2‐year surveillance data. We derived a collective measure for each indicator using the average percentile rank of the related parameters. Alert thresholds for the single impact parameter were set at predefined values and evaluated for its sensitivity, specificity and positive predictive value. Results: For the transmissibility and seriousness of disease parameters, calculation of the percentile rank was simple and independent of a parameter's underlying distribution. For the impact parameter, predefined alert thresholds had high sensitivity and specificity (>80%) but low positive predictive value (15%‐30%). Assessment scales were used to qualitatively classify the activity of an indicator as low, moderate or high together with a confidence level. Conclusion: We applied different methods for threshold setting depending on the attributes of each parameter and indicator. For indicators represented by multiple parameters, an aggregated assessment of the indicator's level of activity and confidence level of the assessment was needed for effective reporting. [ABSTRACT FROM AUTHOR]

Surveillance and reporting of epidemiological features of seasonal influenza mostly are aggregates across all‐ages. We investigated age‐specific differences in distribution of influenza virus (sub)types in tropical Singapore, using laboratory‐confirmed virological data collected under the national influenza surveillance programme from 2011 to 2017. The proportion of influenza‐positive specimens from outpatients with influenza‐like illness was used as an indicator of influenza activity in the community. The highest influenza positivity for age groups of 5 to 14 years and 15 to 64 years coincided in the same month in 5 out of the 7 years under study. Influenza positivity was lowest in young children <5 years of age compared with older age groups. Influenza A(H3N2) was most prevalent in the community except in 2012 when a predominance of influenza B was observed. The dominant virus (sub)type varied across the years in children <5 years and 5 to 14 years of age. Influenza A(H3N2) was the predominant circulating virus subtype among elderly persons aged ≥65 years during the 7‐year period, and among adults aged 15 to 64 years since 2013. Knowledge about the age‐specific differences in distribution of influenza virus (sub)types helps to facilitate better understanding of seasonal epidemics and to inform targeted strategies in prevention and control of influenza virus transmission. Highlight: Influenza peak for age groups of 5–14 years and 15–64 years mostly coincided in the same month.Influenza positivity was lowest in young children <5 years of age.Children <5 years of age experienced a mixture of influenza A and B viruses as the predominant types.Age groups of 5–14 years and 15–64 years were mostly affected by A(H3N2) followed by influenza B.Influenza A(H3N2) was particularly prevalent in elderly persons aged ≥65 years. [ABSTRACT FROM AUTHOR]

Objectives: Since the 1990s, Singapore has experienced periodic dengue epidemics of increasing frequency and magnitude. In the aftermath of the 2004–2005 dengue epidemic, hospitals refined their admission criteria for dengue cases to right-site dengue case management and reduce the burden of healthcare utilization and negative outcomes. In this study, we describe the national trends of hospital admissions for dengue and disease severity in terms of length of stay (LOS), admission to the intensive care unit (ICU) and death in hospital, and case fatality rate (CFR) in Singapore. Methods: We conducted a retrospective study of notified cases and laboratory confirmed dengue patients admitted to all public and private hospitals between 2003 and 2017. Case notifications for dengue and hospitalization records were extracted from national databases. Results: The proportion of dengue cases hospitalized was lower in recent years; 28.9% in the 2013–2014 epidemic, compared to 93.2% in the 2004–2005 epidemic, and 58.1% in the 2007 epidemic. Median LOS remained stable over the years; overall LOS was 3 to 4 days and ICU stay was 2 to 3 days. Less than 2% of hospitalized patients were admitted to the ICU. Overall CFR was low and remained below 0.5%. The proportions of dengue cases hospitalized and patients admitted to the ICU were highest in the elderly aged 65 years and older. Conclusions: While the proportion of dengue cases hospitalized saw a drastic decline due to more selective admission criteria, there was no concomitant increase in adverse outcomes, suggesting that admission criteria were appropriate to focus on severe dengue cases. Further studies are needed to optimize dengue management in older adults who are more likely to be hospitalized with greater disease severity, given the higher proportions of hospitalizations and severe disease among older adults. [ABSTRACT FROM AUTHOR]

Background: From 31 August to 9 September 2015, a total of 150 military personnel at a military institution in Singapore were infected with acute gastroenteritis (AGE) with an attack rate of approximately 3%. This study aimed to determine the epidemiology of the outbreak, investigate its origins, and discuss measures to prevent future occurrences.Methods: After the AGE outbreak was declared on 31 August 2015, symptom surveys, hygiene inspections, and the testing of water, food, and stool samples were initiated. We collected 86 stool samples from AGE cases and 58 samples from food-handlers during the course of the outbreak and these stool samples were tested for 8 bacterial pathogens and 2 viral pathogens (i.e., norovirus and sapovirus).Results: We detected Sapovirus (SaV), group I Norovirus (NoV GI) and group II Norovirus (NoV GII) from the stool samples of AGE cases. Further sequence analyses showed that the AGE outbreak in August was caused mainly by three rarely reported calicivirus novel genotypes: NoV GI.7, NoV GII.17 and SaV GII.3. Control measures implemented focused on the escalation of personal and environmental hygiene, which included the separation of affected and unaffected soldiers, enforcement of rigorous hand-washing and hygiene, raising awareness of food and water safety, and disinfection of communal areas with bleach.Conclusions: This study identified both NoV and SaV as the causative agents for an AGE outbreak at a Singapore military camp in August 2015. This study is also the first to report SaV as one of the main causative agents, highlighting the importance of caliciviruses as causative agents of AGE outbreaks in the Singapore military. As there are no commercially available vaccines against caliciviruses, strict personal hygiene and proper disinfection of environmental surfaces remain crucial to prevent calicivirus outbreak and transmission. [ABSTRACT FROM AUTHOR]

On June 21, 2022, Singapore reported its second ever case of imported monkeypox and first linked to the ongoing multi-country outbreak that has since been declared a public health emergency of international concern. There was quick initiation of public health measures including identification and quarantine of contacts, with post-exposure smallpox vaccination. [ABSTRACT FROM AUTHOR]

To investigate the performance of laboratory methods and clinical case definitions in detecting the viral pathogens for acute respiratory infections (ARIs) from a prospective community cohort and hospital inpatients, nasopharyngeal swabs from cohort members reporting ARIs (community-ARI) and inpatients admitted with ARIs (inpatient-ARI) were tested by Singleplex Real Time-Polymerase Chain Reaction (SRT-PCR), multiplex RT-PCR (MRT-PCR) and pathogen-chip system (PathChip) between April 2012 and December 2013. Community-ARI and inpatient-ARI was also combined with mild and severe cases of influenza from a historical prospective study as mild-ARI and severe-ARI respectively to evaluate the performance of clinical case definitions. We analysed 130 community-ARI and 140 inpatient-ARI episodes (5 inpatient-ARI excluded because multiple pathogens were detected), involving 138 and 207 samples respectively. Detection by PCR declined with days post-onset for influenza virus; decrease was faster for community-ARI than for inpatient-ARI. No such patterns were observed for non-influenza respiratory virus infections. PathChip added substantially to viruses detected for community-ARI only. Clinical case definitions discriminated influenza from other mild-ARI but performed poorly for severe-ARI and for older participants. Rational strategies for diagnosis and surveillance of influenza and other respiratory virus must acknowledge the differences between ARIs presenting in community and hospital settings. [ABSTRACT FROM AUTHOR]

• Influenza vaccine effectiveness (VE) was estimated using respiratory outbreak data. • VE was estimated to reach as high as 67.9% against influenza A(H3N2). • In contrast, estimated VE against influenza A(H1N1)pdm09 was only 35.4%. • Higher effectiveness was also seen in individuals who were recently vaccinated. • Our study provides novel data on influenza vaccine effectiveness in the tropics. Influenza outbreaks occur periodically in Long Term Care Facilities (LTCFs) and vaccination is critical in preventing influenza infections. We evaluated the influenza vaccine effectiveness (VE) during respiratory outbreaks in LTCFs reported to the Ministry of Health, Singapore in 2017. A test-negative design was used to estimate the ratio of the odds of testing positive for influenza among vaccinated individuals to the odds among unvaccinated individuals. The VE was calculated as (1-odds ratio) × 100%. For adjusted VE, the estimates were derived using logistic regression adjusted for age group, gender, month of illness, and number of days from date of illness onset till to swab collection date. Estimates by influenza subtypes and post-vaccination time periods (15–180 days & 181–365 days) were also calculated using stratified data. 264 individuals, with 118 laboratory-confirmed influenza cases [32 A(H1N1)pdm09, 75 A(H3N2), 11 A(untypable)], were included in the analysis. No one was identified to be infected with influenza B. The overall adjusted VE estimate was 40.5% (95% CI: −12.2–68.5%), while the subtype-specific adjusted VE estimates were −43.4% (95% CI: −312.4–50.2%) against A(H1N1)pdm09 and 57.1% (95% CI: 5.7–80.5%) against A(H3N2). At 15–180 days post-vaccination period, the adjusted VEs were 59.3% (95% CI: 18.0–79.8%) against all influenza, 35.4% (95% CI: −123.5–81.3%) against A(H1N1)pdm09 and 67.9% (95% CI: 22.5–86.7%) against A(H3N2). Estimates were not significant at 181–365 days post-vaccination. The influenza vaccine showed varying effectiveness among individuals in Singapore's LTCFs in 2017, with a higher effectiveness among those who were more recently vaccinated. It remains an important tool in preventing influenza infections, especially for those who are at high risk of influenza-related complications. [ABSTRACT FROM AUTHOR]