Outbreak of invasive Group A streptococcus disease in a nursing home in Ireland in February 2023 caused by emm type 18.

An out-of-season increase in cases of invasive Group A streptococcus (iGAS) was observed in Ireland between October 2022 and August 2023. We describe the management of an iGAS outbreak involving three nursing home residents in Ireland in early 2023. A regional Department of Public Health was notified of an iGAS case in a nursing home resident in January 2023. When two further cases among residents were notified 7 days later, an outbreak was declared. Surveillance for GAS/iGAS infection in residents and staff was undertaken. The site was visited to provide infection prevention and control (IPC) support. Isolates were emm typed. A total of 38 residents and 29 staff in contact with resident cases were provided with antibiotic chemoprophylaxis. Seven additional staff with no direct resident contact also received chemoprophylaxis after finding one probable localised GAS infection among them. No more iGAS cases subsequently occurred.Site visit recommendations included advice on terminal cleaning and cleaning of shared equipment, as well as strengthening staff education on hand hygiene and masking. All isolates were of emm subtype 18.12, a subtype not previously detected in Ireland. Key outbreak control measures were rapid delivery of IPC support and chemoprophylaxis. Emm18 is infrequently associated with GAS infections.

Transmission of SARS-CoV-2 arising from international flights arriving in Ireland in December 2020: a descriptive analysis using national surveillance data.

OBJECTIVES: There is limited evidence on the risk of in-flight transmission of SARS-CoV-2. This study estimated the extent of in-flight SARS-CoV-2 transmission on international flights arriving in Ireland during December 2020. STUDY DESIGN: This was a cross-sectional analysis. METHODS: National surveillance data identified all notified cases of COVID-19 who were infectious while travelling on international flights to Ireland during December 2020. Close contacts of cases were tested for SARS-CoV-2, and the results were collated to estimate the pooled secondary attack rate across all flights. Laboratory and epidemiological data were obtained from the Health Service Executive Covid Care Tracker, a national database of COVID-19 cases in Ireland. RESULTS: A total of 165 infectious cases of COVID-19 were identified on 134 incoming flights; 40.0% were symptomatic on board. There were 2099 flight close contacts identified, of whom 40.9% had results of a SARS-CoV-2 polymerase chain reaction test within 14 days of arrival. The pooled secondary attack rate for these contacts was 7.0% and was higher among those on flights of ≥5-hour duration (P = 0.008). More than half (59.1%) of close contacts had no SARS-CoV-2 test result recorded; the reasons included incorrect or absent contact details (26.5%) and no response when contacted (17.8%). CONCLUSIONS: In this national study investigating transmission of SARS-CoV-2 from international flights arriving into Ireland, the pooled secondary attack rate was 7.0%. International travel is likely to have contributed to the third wave of SARS-CoV-2 infections in Ireland in early 2021. Application of non-pharmaceutical interventions remains central to mitigating the risk of in-flight transmission.

Numbers of close contacts of individuals infected with SARS-CoV-2 and their association with government intervention strategies.

BACKGROUND: Contact tracing is conducted with the primary purpose of interrupting transmission from individuals who are likely to be infectious to others. Secondary analyses of data on the numbers of close contacts of confirmed cases could also: provide an early signal of increases in contact patterns that might precede larger than expected case numbers; evaluate the impact of government interventions on the number of contacts of confirmed cases; or provide data information on contact rates between age cohorts for the purpose of epidemiological modelling. We analysed data from 140,204 close contacts of 39,861 cases in Ireland from 1st May to 1st December 2020. RESULTS: Negative binomial regression models highlighted greater numbers of contacts within specific population demographics, after correcting for temporal associations. Separate segmented regression models of the number of cases over time and the average number of contacts per case indicated that a breakpoint indicating a rapid decrease in the number of contacts per case in October 2020 preceded a breakpoint indicating a reduction in the number of cases by 11 days. CONCLUSIONS: We found that the number of contacts per infected case was overdispersed, the mean varied considerable over time and was temporally associated with government interventions. Analysis of the reported number of contacts per individual in contact tracing data may be a useful early indicator of changes in behaviour in response to, or indeed despite, government restrictions. This study provides useful information for triangulating assumptions regarding the contact mixing rates between different age cohorts for epidemiological modelling.

Estimation of the serial interval and proportion of pre-symptomatic transmission events of COVID- 19 in Ireland using contact tracing data.

BACKGROUND: The serial interval is the period of time between the onset of symptoms in an infector and an infectee and is an important parameter which can impact on the estimation of the reproduction number. Whilst several parameters influencing infection transmission are expected to be consistent across populations, the serial interval can vary across and within populations over time. Therefore, local estimates are preferable for use in epidemiological models developed at a regional level. We used data collected as part of the national contact tracing process in Ireland to estimate the serial interval of SARS-CoV-2 infection in the Irish population, and to estimate the proportion of transmission events that occurred prior to the onset of symptoms. RESULTS: After data cleaning, the final dataset consisted of 471 infected close contacts from 471 primary cases. The median serial interval was 4 days, mean serial interval was 4.0 (95% confidence intervals 3.7, 4.3) days, whilst the 25th and 75th percentiles were 2 and 6 days respectively. We found that intervals were lower when the primary or secondary case were in the older age cohort (greater than 64 years). Simulating from an incubation period distribution from international literature, we estimated that 67% of transmission events had greater than 50% probability of occurring prior to the onset of symptoms in the infector. CONCLUSIONS: Whilst our analysis was based on a large sample size, data were collected for the primary purpose of interrupting transmission chains. Similar to other studies estimating the serial interval, our analysis is restricted to transmission pairs where the infector is known with some degree of certainty. Such pairs may represent more intense contacts with infected individuals than might occur in the overall population. It is therefore possible that our analysis is biased towards shorter serial intervals than the overall population.

Impact of Implementing Preanalytical Laboratory Standards on the Diagnosis of Gestational Diabetes Mellitus: A Prospective Observational Study.

BACKGROUND: Gestational diabetes mellitus (GDM) is associated with adverse pregnancy outcomes, but risk is reduced with identification and early treatment. Glucose measurements are affected by preanalytical sample handling, such as temperature of storage, phlebotomy-analysis interval, and use of a glycolysis inhibitor. We evaluated glucose concentrations and the incidence of GDM after strict implementation of the American Diabetes Association (ADA) preanalytical guidelines, compared with usual hospital conditions. METHODS: Women screened selectively for GDM at 24-32 weeks' gestation were recruited at their convenience before a 75-g oral glucose tolerance test. Paired samples were taken: the first sample followed ADA recommendations and was transferred to the laboratory on an iced slurry for immediate separation and analysis (research conditions), and the second sample was not placed on ice and was transferred according to hospital practice (usual conditions). RESULTS: Of samples from 155 women, the mean fasting, 1-h, and 2-h results were 90.0 (12.6) mg/dL [5.0 (0.7) mmol/L], 142.2 (43.2) mg/dL [7.9 (2.4) mmol/L], and 102.6 (32.4) mg/dL [5.7 (1.8) mmol/L], respectively, under research conditions, and 81 (12.6) mg/dL [4.5 (0.7) mmol/L], 133.2 (41.4) mg/dL [7.4 (2.3) mmol/L], and 99 (32.4) mg/dL [5.5 (1.8) mmol/L] under usual conditions (all P < 0.0001). GDM was diagnosed in 38.1% (n = 59) under research conditions and 14.2% (n = 22) under usual conditions (P < 0.0001). The phlebotomy-analysis interval for the fasting, 1-h, and 2-h samples was 20 (9), 17 (10), and 17 (9) min under research conditions and 162 (19), 95 (23), and 32 (19) min under usual conditions (all P < 0.0001). All cases of GDM were diagnosed on fasting or 1-h samples; the 2-h test diagnosed no additional cases. CONCLUSIONS: Implementation of ADA preanalytical glucose sample handling recommendations resulted in higher mean glucose concentrations and 2.7-fold increased detection of GDM compared with usual hospital practices.