Adjusting for Case Under-Ascertainment in Estimating RSV Hospitalisation Burden of Older Adults in High-Income Countries: a Systematic Review and Modelling Study

INTRODUCTION

Previous studies suggest diagnostic testing characteristics (i.e. variations in clinical specimens and diagnostic tests) can contribute to underestimation of RSV disease burden. We aimed to improve the understanding of RSV hospitalisation burden in older adults (aged ≥ 65 years) in high-income countries through adjusting for case under-ascertainment.

METHODS

We conducted a systematic review to include data on RSV-associated acute respiratory infection (ARI) hospitalisation burden in older adults in high-income countries. To adjust for case under-ascertainment, we developed a two-step framework that incorporated empirical data on the RSV detection proportion of different clinical specimens and testing approaches as well as their statistical uncertainty. We estimated the unadjusted and adjusted RSV-associated hospitalisation burden through multilevel random-effects meta-analysis. We further explored RSV-associated in-hospital mortality burden.

RESULTS

We included 12 studies with eligible RSV hospitalisation burden data. We estimated that pooled unadjusted hospitalisation rate was 157 per 100,000 (95% CI 98-252) for adults aged ≥ 65 years; the rate was adjusted to 347 per 100,000 (203-595) after accounting for under-ascertainment. The adjusted rate could be translated into 787,000 (460,000-1,347,000) RSV-associated hospitalisations in high-income countries in 2019, which was about 2.2 times the unadjusted estimate. Stratified analysis by age group showed that the adjusted rate increased with age, from 231 per 100,000 in adults aged 65-74 years to 692 per 100,000 in adults aged > 85 years. The in-hospital case fatality ratio of RSV was 6.1% (3.3-11.0) and the total RSV-associated in-hospital deaths in high-income countries in 2019 could be between 22,000 and 47,000.

CONCLUSION

This study improves the understanding of RSV-associated hospitalisation burden in older adults and shows that the true RSV-associated hospitalisation burden could be 2.2 times what was reported in existing studies. This study has implications for calculating the benefit of interventions to treat and prevent RSV-associated disease.

Severity of Omicron (B.1.1.529) and Delta (B.1.617.2) SARS-CoV-2 infection among hospitalised adults: A prospective cohort study in Bristol, United Kingdom

Background

There is an urgent public health need to evaluate disease severity in adults hospitalised with Delta and Omicron SARS-CoV-2 variant infections. However, limited data exist assessing severity of disease in adults hospitalised with Omicron SARS-CoV-2 infections, and to what extent patient-factors, including vaccination, age, frailty and pre-existing disease, affect variant-dependent disease severity.

Methods

A prospective cohort study of adults (≥18 years of age) hospitalised with acute lower respiratory tract disease at acute care hospitals in Bristol, UK conducted over 10-months. Delta or Omicron SARS-CoV-2 infection was defined by positive SARS-CoV-2 PCR and variant identification or inferred by dominant circulating variant. We constructed adjusted regression analyses to assess disease severity using three different measures: FiO₂ >28% (fraction inspired oxygen), World Health Organization (WHO) outcome score >5 (assessing need for ventilatory support), and hospital length of stay (LOS) >3 days following admission for Omicron or Delta infection.

Findings

Independent of other variables, including vaccination, Omicron variant infection in hospitalised adults was associated with lower severity than Delta. Risk reductions were 58%, 67%, and 16% for supplementary oxygen with >28% FiO₂ [Relative Risk (RR) = 0.42 (95%CI: 0.34-0.52), P < 0.001], WHO outcome score >5 [RR = 0.33 (95%CI: 0.21-0.50), P < 0.001], and to have had a LOS > 3 days [RR = 0.84 (95%CI: 0.76-0.92), P < 0.001]. Younger age and vaccination with two or three doses were also independently associated with lower COVID-19 severity.

Interpretation

We provide reassuring evidence that Omicron infection results in less serious adverse outcomes than Delta in hospitalised patients. Despite lower severity relative to Delta, Omicron infection still resulted in substantial patient and public health burden and an increased admission rate of older patients with Omicron which counteracts some of the benefit arising from less severe disease.

Funding

AvonCAP is an investigator-led project funded under a collaborative agreement by Pfizer.

Detection of SARS-CoV-2 infection by saliva and nasopharyngeal sampling in frontline healthcare workers: An observational cohort study

BACKGROUND

The SARS-CoV-2 pandemic has caused an unprecedented strain on healthcare systems worldwide, including the United Kingdom National Health Service (NHS). We conducted an observational cohort study of SARS-CoV-2 infection in frontline healthcare workers (HCW) working in an acute NHS Trust during the first wave of the pandemic, to answer emerging questions surrounding SARS-CoV-2 infection, diagnosis, transmission and control.

METHODS

Using self-collected weekly saliva and twice weekly combined oropharyngeal/nasopharyngeal (OP/NP) samples, in addition to self-assessed symptom profiles and isolation behaviours, we retrospectively compared SARS-CoV-2 detection by RT-qPCR of saliva and OP/NP samples. We report the association with contemporaneous symptoms and isolation behaviour.

RESULTS

Over a 12-week period from 30th March 2020, 40·0% (n = 34/85, 95% confidence interval 31·3-51·8%) HCW had evidence of SARS-CoV-2 infection by surveillance OP/NP swab and/or saliva sample. Symptoms were reported by 47·1% (n = 40) and self-isolation by 25·9% (n = 22) participants. Only 44.1% (n = 15/34) participants with SARS-CoV-2 infection reported any symptoms within 14 days of a positive result and only 29·4% (n = 10/34) reported self-isolation periods. Overall agreement between paired saliva and OP/NP swabs was 93·4% (n = 211/226 pairs) but rates of positive concordance were low. In paired samples with at least one positive result, 35·0% (n = 7/20) were positive exclusively by OP/NP swab, 40·0% (n = 8/20) exclusively by saliva and in only 25·0% (n = 5/20) were the OP/NP and saliva result both positive.

CONCLUSIONS

HCW are a potential source of SARS-CoV-2 transmission in hospitals and symptom screening will identify the minority of infections. Without routine asymptomatic SARS-CoV-2 screening, it is likely that HCW with SARS-CoV-2 infection would continue to attend work. Saliva, in addition to OP/NP swab testing, facilitated ascertainment of symptomatic and asymptomatic SARS-CoV-2 infections. Combined saliva and OP/NP swab sampling would improve detection of SARS-CoV-2 for surveillance and is recommended for a high sensitivity strategy.

Prevalence of Pneumococcal Serotypes in Community-Acquired Pneumonia among Older Adults in Italy: A Multicenter Cohort Study

Pneumococcal community-acquired pneumonia (CAP) is a leading cause of mortality. Following the introduction of pneumococcal conjugate vaccines (PCVs) in children, a decrease in the burden of the disease was reported. In parallel, an increase in non-vaccine serotypes was also noted. The objective of this study was to assess the current serotype-specific epidemiology of pneumococci among Italian older adults hospitalized for CAP. A prospective study was conducted between 2017 and 2020 in four Italian regions. Subjects aged ≥65 years hospitalized with confirmed CAP were tested for pneumococci using both pneumococcal urinary antigen and serotype-specific urine antigen tests able to identify all 24 serotypes included in the available vaccines. Of the 1155 CAP cases, 13.1% were positive for pneumococci. The most prevalent serotypes were 3 (2.0%), 8 (1.7%), 22F (0.8 %) and 11A (0.7%). These serotypes are all included in the newly licensed PCV20. The serotypes included in PCV13, PCV15 and PCV20 contributed to 3.3%, 4.4% and 7.5% of the CAP cases, respectively. In the context of a low PCV13 coverage among older adults and a high PCV coverage in children, a substantial proportion of CAP is caused by PCV13 serotypes. Higher valency PCV15 and PCV20 may provide additional benefits for the prevention of CAP in vaccinated older adults.

371. Adding sputum and saliva to nasopharyngeal swab samples for PCR detection of Respiratory Syncytial Virus in adults hospitalized with acute respiratory illness may double case detection

Background

In hospitalized patients, nasopharyngeal (NP) swabs are the most common samples obtained for Respiratory Syncytial Virus (RSV) PCR testing. However, adding sputum is known to increase diagnostic yield, and saliva has been successfully used for viral respiratory infection diagnosis. We sought to compare RSV prevalence detected by PCR testing of NP swab alone versus NP swab plus saliva and sputum in adult patients hospitalized with acute respiratory illness (ARI).

Methods

This ongoing, prospective cohort study enrolled patients aged ≥40 years hospitalized for ARI in 4 hospitals in Louisville, Kentucky (Season 1: 27 Dec 21 – 1 Apr 22). NP swab, saliva, and sputum samples were obtained at enrollment or scavenged from standard-of-care specimens (all collected ≤3 days of admission), and PCR tested with Luminex ARIES FluA/B/RSV platform. We produced Venn diagrams of RSV positive samples by sample type for all patients and restricted to those with all 3 sample types. RSV prevalence for NP swab alone was calculated as number of patients with RSV-positive NP swabs divided by total number of patients tested. RSV prevalence by NP swab plus saliva and sputum was calculated as number of patients with RSV-positive NP swab, saliva, or sputum samples divided by total number of patients tested.

Results

We enrolled 653 patients and collected NP swabs (100% of patients), saliva (96%), and sputum (43% overall and 93% of the 303 sputum-producing patients). Among all patients, 28 patients tested RSV positive (Figure 1A), and when restricted to those with all 3 samples (Figure 1B), 14 tested positive. The overall cohort’s RSV prevalence by NP swab alone was 1.8% (12/653) and by NP swab plus saliva and/or sputum was 4.3% (28/653): 2.33 times higher with addition of saliva and sputum samples. Among patients with all 3 specimen types, the RSV prevalence increase was the same, and none were positive by NP swab only. Figure 1.

1351. A Retrospective Database Study of Lyme Borreliosis Incidence and Distribution in Poland from 2015 to 2019

Background

Lyme borreliosis (LB), a tick-borne disease caused by Borrelia burgdorferi sensu lato, has been subject to mandatory public health surveillance since 1996 in Poland. Here, the incidence, temporal trends, and geographical distribution of LB and its manifestations in Poland are described for the period 2015-2019.

Methods

This retrospective incidence study of LB and its manifestations in Poland was based on the data sent to the National Institute of Public Health (NIPH-NIH–NRI) by district sanitary-epidemiological stations using the electronic Epidemiological Records Registration System and data from the National Database on Hospitalization. LB and its manifestations were reported in two categories- probable and confirmed (through laboratory tests). Incidence rates were calculated using the population data from the Central Statistical Office of Poland.

Results

In Poland, a total of 94,715 cases of LB with an overall mean incidence of 49.3 cases per 100,000 population were reported between 2015-2019. Cases increased from 2015 (11,945) to 2016 (20,857), and then remained stable through 2019. LB was more common among women (55.7%). The highest incidence rates occurred among &gt;50-year-olds, with a peak in 65-69-year-olds. 48,717 persons with LB were hospitalized in the 5-year period, with higher number of hospitalizations in age groups 55-69 years old. Erythema migrans and Lyme arthritis were the most common manifestations of LB with incidence rates of 36.2 and 15.8 per 100,000 population, respectively. EM accounted for approximately 74% of all manifestations of LB. The highest number of cases were recorded in the 3rd and 4th quarters of the year (July – December). Incidence rates in the East and Northeastern regions (Podlaskie, Lubelskie, and Warmińsko-Mazurskie voivodeships) of the country were higher than the national average. These regions correspond to greater forest cover and/or agricultural areas.

Time trend of LB cases and incidence in Poland, 2015-2019.

Conclusion

LB is endemic in all regions of Poland, and many regions reported high incidence rates. LB is reported year-round in Poland. Thus, large variations in temporal and spatially granular incidence rates highlight the need for targeted prevention strategies, such as vaccines.

Disclosures

Jozica Skufca, Epidemiologist, p95: Paid by Pfizer to perform the study Archana Nagarajan, Ph.D., P95: Paid by Pfizer to perform the study Andreas Pilz, PhD, Pfizer: Employee|Pfizer: Stocks/Bonds|Pfizer: Stocks/Bonds Andrew Vyse, Ph.D., Pfizer: Stocks/Bonds Elizabeth Begier, M.D., M.P.H., Pfizer: Employee|Pfizer: Stocks/Bonds Mendwas Dzingina, Ph.D., Pfizer: Stocks/Bonds Maxim Blum, Ph.D., P95: Paid by Pfizer to perform the study Margarita Riera, MD, MPH, P95: Paid by Pfizer to perform the study Bradford Gessner, MD, MPH, Pfizer: Stocks/Bonds James Stark, Ph.D., Pfizer: Stocks/Bonds.

2207. Rates of Lower Respiratory Tract Infections Among US Adults Aged ≥18 Years With and Without Chronic Medical Conditions

Background

While it is widely recognized that older adults and adults with chronic medical conditions are at increased risk of lower respiratory tract infections (LRTI), available evidence on the magnitude of increased risk is limited.

Methods

A retrospective observational cohort study using IBM MarketScan Commercial/Medicare Databases (2016–2019) was conducted. The study population included all adults (age ≥ 18 years) and was stratified by age and comorbidity profile (with vs. without high-risk conditions, based on recommendations for influenza vaccination in the United States). LRTI was ascertained on an overall basis as well as by causative pathogen (e.g., respiratory syncytial virus [RSV]) based on corresponding diagnosis codes, and was classified based on care setting (hospital, emergency department [ED], physician office/hospital outpatient [PO/HO]). Incidence rates (and relative rates [RRs]) were generated by age, and within each age group, by comorbidity profile.

Results

Using adults aged 18-34 years as the reference, RR of LRTI generally increased with older age across care settings, with the most marked increase for hospitalizations: for hospitalized-LRTI, RRs ranged from 1.7 for 35-49 years to 78.9 for ≥ 85 years; for ED-LRTI and PO/HO-LRTI, RRs ranged from 1.0 to 3.4 and from 1.4 to 2.1, respectively (Table). Within age groups, LRTI rates were also consistently higher among adults with versus without high-risk conditions: for hospitalized-LRTI, RRs ranged from 9.9 to 21.1; for ED-LRTI, from 2.3 to 3.2; and for PO/HO-LRTI, from 1.6 to 2.5. Age-specific RRs of hospitalized-LRTI due to RSV were largely comparable to overall LRTI results; age-specific RRs for other care settings, and RRs for adults with versus without high-risk conditions across care settings, were generally higher for LRTI due to RSV.

Conclusion

LRTI incidence, especially for events requiring acute inpatient care, is markedly higher among older adults and adults of all ages with chronic medical conditions. Effective vaccines against respiratory pathogens could help reduce this elevated risk of LRTI.

Disclosures

Derek Weycker, Ph.D., Pfizer Inc.: Grant/Research Support Ahuva Averin, M.P.P., Pfizer Inc.: Grant/Research Support Linnea Houde, M.S., Pfizer Inc.: Grant/Research Support Kevin Ottino, M.H.S., Pfizer Inc.: Grant/Research Support Kimberly M. Shea, Ph.D., M.P.H., Pfizer: Employee|Pfizer: Stocks/Bonds Bradford J. Gessner, M.D., M.P.H., Pfizer Inc.: Employee|Pfizer Inc.: Stocks/Bonds Kari Yacisin, M.D., Pfizer Inc.: Employee|Pfizer Inc.: Stocks/Bonds Daniel Curcio, M.Sc., Pfizer Inc.: Employee|Pfizer Inc.: Stocks/Bonds Elizabeth Begier, M.D., M.P.H., Pfizer: Employee|Pfizer: Stocks/Bonds Mark Rozenbaum, Ph.D., M.B.A., Pfizer Inc.: Employee|Pfizer Inc.: Stocks/Bonds.

1352. Exploring spatial and temporal trends in the incidence of Lyme borreliosis in Finland using surveillance data, 2015 - 2020

Background

Lyme borreliosis (LB) is a tick-borne zoonotic disease endemic in many European countries, including Finland. We describe the incidence, time trends and geographical distribution of LB in Finland for the period 2015–2020. The data generated can help inform public health policy, including prevention strategies.

Methods

We retrieved online available LB cases and incidence from two Finnish national databases. Microbiologically confirmed disseminated LB cases were identified from The National Infectious Disease Register (NIDR) and clinically diagnosed LB cases, from the National Register of Primary Health Care Visits (Avohilmo), with the total LB cases equal to the sum from these two sources. Both registers contain data from the entire country and by hospital districts (HDs) and municipalities. Total LB incidence was calculated as the sum of microbiologically confirmed and clinically diagnosed LB cases divided by the population size.

Results

A total of 33,185 LB cases were reported over the 2015-2020 period, of which 12,590 (38%) were microbiologically confirmed and 20,595 (62%), clinically diagnosed. The average annual national incidence for total, microbiologically confirmed and clinically diagnosed LB were, respectively, 99.6, 38.1, and 61.4 per 100,000 population. The overall LB incidence was highest in the south to southwestern coastal areas by the Baltic Sea and in eastern areas, with average annual incidences of 109.0 to 207.3/100,000. The Ahvenanmaa Island was a hyperendemic region with an average annual incidence of 2,473.9/100,000 and the only HD to report more microbiologically confirmed cases (69%) as compared to clinically diagnosed cases. The highest incidence rates were among persons aged over 60 years, peaking at age 70–74 years. Below 40 years, the highest incidence rates were observed among 5-9-year-olds. Most cases were reported between May and October, with a peak in July and August.

Average annual incidence (per 100,000 residents) by the Finnish hospital districts (HD) from 2015-2020. A) Clinically diagnosed LB; B) Microbiologically confirmed LB; C) Both combined, clinically diagnosed, and microbiologically confirmed LB.

Conclusion

The incidence of LB in Finland is among the highest in Europe but varied substantially by HD and many regions reported incidence much higher than the national average. These regions also corresponded to high population density areas, suggesting preventive measures such as vaccines may be an efficient use of resources.

Disclosures

Jozica Skufca, Epidemiologist, p95: Paid by Pfizer to perform the study Nick DeSmedt, Masters in Computer Engineering, P95: P95 was paid by Pfizer to perform the study Andreas Pilz, PhD, Pfizer: Employee|Pfizer: Stocks/Bonds|Pfizer: Stocks/Bonds Andrew Vyse, Ph.D., Pfizer: Stocks/Bonds Elizabeth Begier, M.D., M.P.H., Pfizer: Employee|Pfizer: Stocks/Bonds Margarita Riera, MD, MPH, P95: Paid by Pfizer to perform the study Maxim Blum, Ph.D., P95: Paid by Pfizer to perform the study Bradford Gessner, MD, MPH, Pfizer: Stocks/Bonds James Stark, Ph.D., Pfizer: Stocks/Bonds.

2208. Rates of Medically-Attended RSV among US Adults: A Systematic Review and Meta-Analysis

Background

Adult respiratory syncytial virus (RSV) vaccines are in late stages of development. A comprehensive synthesis of adult RSV burden is needed to inform public health decision-making.

Methods

We performed a systematic review and meta-analysis of studies describing the incidence of medically-attended RSV (MA-RSV) among US adults. We also identified studies reporting nasopharyngeal (NP) or nasal swab RT-PCR results with paired serology (four-fold-rise) or sputum (RT-PCR) to calculate RSV detection ratios quantifying improved diagnostic yield after adding a second specimen type (ie, serology or sputum).

Results

We identified 14 studies with 15 unique MA-RSV incidence estimates, all based on NP or nasal swab RT-PCR testing alone. Pooled annual RSV-associated incidence per 100,000 adults ≥65 years of age was 178 (95%CI: 152‒204; n=8 estimates) hospitalizations (4 prospective studies: 189; 4 model-based studies: 157), 133 (95%CI: 0‒319, n=2) emergency department (ED) admissions, and 1519 (95%CI: 1109‒1929, n=3) outpatient visits. Based on 6 studies, RSV detection was ∼1.5 times higher when adding paired serology or sputum. After adjustment for this increased yield, annual RSV-associated rates per 100,000 adults ≥65 years were 267 hospitalizations (UI: 228‒306) (prospective: 282; model-based: 236), 200 ED admissions (UI: 0‒478), and 2278 outpatient visits (UI: 1663‒2893). Persons < 65 years with chronic medical conditions were 1.2−28 times more likely to be hospitalized for RSV depending on risk condition.

Conclusion

The true burden of RSV has been underestimated and is significant among older adults and individuals with chronic medical conditions. A highly effective adult RSV vaccine would have substantial public-health impact.

Disclosures

John M. McLaughlin, PhD, Pfizer: Employee|Pfizer: Stocks/Bonds Farid L. Khan, MPH, Pfizer: Employee|Pfizer: Stocks/Bonds Elizabeth Begier, M.D., M.P.H., Pfizer: Employee|Pfizer: Stocks/Bonds David Swerdlow, MD, Pfizer: Advisor/Consultant|Pfizer: Stocks/Bonds Luis Jodar, PhD, Pfizer: Employee|Pfizer: Stocks/Bonds Ann R. Falsey, MD, BioFire Diagnostics: Grant/Research Support|Janssen: Grant/Research Support|Merck, Sharp and Dohme: Grant/Research Support|Novavax: Advisor/Consultant|Pfizer: Grant/Research Support.

1354. Incidence, time trends and geographic distribution of Lyme neuroborreliosis in Denmark using public surveillance data, 2015-2019

Background

Lyme neuroborreliosis (LNB) is a potentially severe manifestation of Lyme borreliosis (LB), a spirochetal tick-borne infectious disease caused by Borrelia burgdorferi. We describe the incidence, time trends and geographic distribution of LNB in Denmark, with the aim to inform public health policy, including the potential use of new vaccines under development.

Methods

Based on the case definition for LNB (clinical diagnosis of LB plus detection of antibodies in blood and cerebral spinal fluid [confirmed case], OR clinical symptoms compatible with LNB and detection of antibodies in blood [probable case]), we obtained cases reported by laboratories and physicians (2015–2019) from the online platform maintained by the Statens Serum Institut (SSI). The LNB incidence (per 100,000 persons) was calculated by dividing LNB cases by the population data (denominator) obtained from Statistics Denmark.

Results

Between 2015 and 2019, laboratories reported annually 162 to 200 LNB cases, while physicians reported 48 to 68 cases (Figure). The annual LNB incidence notified by laboratories ranged from 2.8 (95% CI: 2.4‒3.3) to 3.4 (95% CI: 3.0‒4.0) per 100,000 persons for the 5 study years. The average annual LNB incidence per 100,000 persons for 5 Danish regions ranged from 2.3 to 3.3; for 11 provinces, from 1.9 to 7.6; and for 98 municipalities, from 0 to 22.1. Incidence peaks occurred in persons 5‒14 and 65‒74 years of age. Higher incidences were observed among males versus females in all age groups. LNB cases were reported throughout the year, with peaks in July to September.

Number of LNB cases and annual incidence (per 100,000 population) notified by (A)physicians and (B) laboratories

Conclusion

LNB incidence in Denmark is moderate with no evidence of decline. Cases occurred across all regions but were focally concentrated among residents of some municipalities. By analyzing and reporting spatially granular data, we could identify areas with the highest LNB incidence. This may assist policy makers with assessing the efficiency of geographically targeted versus national prevention interventions, including vaccines should these be licensed. To this end, expanding the current surveillance system to include other manifestations of LB would be valuable to better understand geographic endemicity.

Disclosures

Jozica Skufca, Epidemiologist, p95: Paid by Pfizer to perform the study Nick DeSmedt, Masters in Computer Engineering, P95: P95 was paid by Pfizer to perform the study Andreas Pilz, PhD, Pfizer: Employee|Pfizer: Stocks/Bonds|Pfizer: Stocks/Bonds Andrew Vyse, Ph.D., Pfizer: Stocks/Bonds Elizabeth Begier, M.D., M.P.H., Pfizer: Employee|Pfizer: Stocks/Bonds Maxim Blum, Ph.D., P95: Paid by Pfizer to perform the study Margarita Riera, MD, MPH, P95: Paid by Pfizer to perform the study Bradford Gessner, MD, MPH, Pfizer: Stocks/Bonds Mette Skovdal, Ph.D., Pfizer Denmark: Stocks/Bonds James Stark, Ph.D., Pfizer: Stocks/Bonds.

Human Infection Challenge with Serotype 3 Pneumococcus

Rationale: Streptococcus pneumoniae serotype 3 (SPN3) is a cause of invasive pneumococcal disease and associated with low carriage rates. Following the introduction of pediatric 13-valent pneumococcal conjugate vaccine (PCV13) programs, SPN3 declines are less than other vaccine serotypes and incidence has increased in some populations coincident with a shift in predominant circulating SPN3 clade, from I to II. A human challenge model provides an effective means for assessing the impact of PCV13 on SPN3 in the upper airway. Objectives: To establish SPN3's ability to colonize the nasopharynx using different inoculum clades and doses, and the safety of an SPN3 challenge model. Methods: In a human challenge study involving three well-characterized and antibiotic-sensitive SPN3 isolates (PFESP306 [clade Ia], PFESP231 [no clade], and PFESP505 [clade II]), inoculum doses (10,000, 20,000, 80,000, and 160,000 cfu/100 μl) were escalated until maximal colonization rates were achieved, with concurrent acceptable safety. Measurement and Main Results: Presence and density of experimental SPN3 nasopharyngeal colonization in nasal wash samples, assessed using microbiological culture and molecular methods, on Days 2, 7, and 14 postinoculation. A total of 96 healthy participants (median age 21, interquartile range 19-25) were inoculated (n = 6-10 per dose group, 10 groups). Colonization rates ranged from 30.0-70.0% varying with dose and isolate. 30.0% (29/96) reported mild symptoms (82.8% [24/29] developed a sore throat); one developed otitis media requiring antibiotics. No serious adverse events occurred. Conclusions: An SPN3 human challenge model is feasible and safe with comparable carriage rates to an established Serotype 6B human challenge model. SPN3 carriage may cause mild upper respiratory symptoms.

Incidence of Lyme neuroborreliosis in Denmark: Exploring observed trends using public surveillance data, 2015-2019

Lyme neuroborreliosis (LNB) can be a serious manifestation of Lyme borreliosis. We describe the incidence, time trends and geographic distribution of LNB in Denmark. We obtained LNB cases reported by laboratories and physicians (2015-2019) from the online platform maintained by the Statens Serum Institut (SSI) (2021b). The LNB incidence (per 100,000 persons) was calculated by dividing LNB cases by the population data (denominator) obtained from Statistics Denmark (2021). Between 2015 and 2019, laboratories reported annually 162 to 200 LNB cases, while physicians reported 48 to 68 cases. The annual LNB incidence notified by laboratories ranged from 2.8 (95% CI: 2.4‒3.3) to 3.4 (95% CI: 3.0‒4.0) per 100,000 persons for the 5 study years. The average annual LNB incidence per 100,000 persons for 5 Danish regions ranged from 2.3 to 3.3; for 11 provinces, from 1.9 to 7.6; and for 98 municipalities, from 0 to 22.1. Incidence peaks occurred in persons 5‒14 and 65‒74 years of age. Higher incidences were observed among males versus females in all age groups. LNB cases were reported throughout the year, with peaks in July to September. Notified LNB incidence in Denmark was moderate with no evidence of decline. Cases occurred across all regions but were focally concentrated among residents of some municipalities. Expanding the current surveillance system to include other manifestations of LB would be valuable to better understand geographic endemicity to inform targeted preventive measures.

Incidence of community acquired lower respiratory tract disease in Bristol, UK during the COVID-19 pandemic: A prospective cohort study

Background

The emergence of COVID-19 and public health measures implemented to reduce SARS-CoV-2 infections have both affected acute lower respiratory tract disease (aLRTD) epidemiology and incidence trends. The severity of COVID-19 and non-SARS-CoV-2 aLRTD during this period have not been compared in detail.

Methods

We conducted a prospective cohort study of adults age ≥18 years admitted to either of two acute care hospitals in Bristol, UK, from August 2020 to November 2021. Patients were included if they presented with signs or symptoms of aLRTD (e.g., cough, pleurisy), or a clinical or radiological aLRTD diagnosis.

Findings

12,557 adult aLRTD hospitalisations occurred: 10,087 were associated with infection (pneumonia or non-pneumonic lower respiratory tract infection [NP-LRTI]), 2161 with no infective cause, with 306 providing a minimal surveillance dataset. Confirmed SARS-CoV-2 infection accounted for 32% (3178/10,087) of respiratory infections. Annual incidences of overall, COVID-19, and non- SARS-CoV-2 pneumonia were 714.1, 264.2, and 449.9, and NP-LRTI were 346.2, 43.8, and 302.4 per 100,000 adults, respectively. Weekly incidence trends in COVID-19 aLRTD showed large surges (median 6.5 [IQR 0.7-10.2] admissions per 100,000 adults per week), while other infective aLRTD events were more stable (median 14.3 [IQR 12.8-16.4] admissions per 100,000 adults per week) as were non-infective aLRTD events (median 4.4 [IQR 3.5-5.5] admissions per 100,000 adults per week).

Interpretation

While COVID-19 disease was a large component of total aLRTD during this pandemic period, non- SARS-CoV-2 infection still caused the majority of respiratory infection hospitalisations. COVID-19 disease showed significant temporal fluctuations in frequency, which were less apparent in non-SARS-CoV-2 infection. Despite public health interventions to reduce respiratory infection, disease incidence remains high.

Funding

AvonCAP is an investigator-led project funded under a collaborative agreement by Pfizer.

Incidence of community acquired lower respiratory tract disease in Bristol, UK during the COVID-19 pandemic: A prospective cohort study

BACKGROUND

The emergence of COVID-19 and public health measures implemented to reduce SARS-CoV-2 infections have both affected acute lower respiratory tract disease (aLRTD) epidemiology and incidence trends. The severity of COVID-19 and non-SARS-CoV-2 aLRTD during this period have not been compared in detail.

METHODS

We conducted a prospective cohort study of adults age ≥18 years admitted to either of two acute care hospitals in Bristol, UK, from August 2020 to November 2021. Patients were included if they presented with signs or symptoms of aLRTD (e.g., cough, pleurisy), or a clinical or radiological aLRTD diagnosis.

FINDINGS

12,557 adult aLRTD hospitalisations occurred: 10,087 were associated with infection (pneumonia or non-pneumonic lower respiratory tract infection [NP-LRTI]), 2161 with no infective cause, with 306 providing a minimal surveillance dataset. Confirmed SARS-CoV-2 infection accounted for 32% (3178/10,087) of respiratory infections. Annual incidences of overall, COVID-19, and non- SARS-CoV-2 pneumonia were 714.1, 264.2, and 449.9, and NP-LRTI were 346.2, 43.8, and 302.4 per 100,000 adults, respectively. Weekly incidence trends in COVID-19 aLRTD showed large surges (median 6.5 [IQR 0.7-10.2] admissions per 100,000 adults per week), while other infective aLRTD events were more stable (median 14.3 [IQR 12.8-16.4] admissions per 100,000 adults per week) as were non-infective aLRTD events (median 4.4 [IQR 3.5-5.5] admissions per 100,000 adults per week).

INTERPRETATION

While COVID-19 disease was a large component of total aLRTD during this pandemic period, non- SARS-CoV-2 infection still caused the majority of respiratory infection hospitalisations. COVID-19 disease showed significant temporal fluctuations in frequency, which were less apparent in non-SARS-CoV-2 infection. Despite public health interventions to reduce respiratory infection, disease incidence remains high.

FUNDING

AvonCAP is an investigator-led project funded under a collaborative agreement by Pfizer.

Protocol for a phase IV double-blind randomised controlled trial to investigate the effect of the 13-valent pneumococcal conjugate vaccine and the 23-valent pneumococcal polysaccharide vaccine on pneumococcal colonisation using the experimental human pneumococcal challenge model in healthy adults (PREVENTING PNEUMO 2)

INTRODUCTION

Despite widely available vaccinations, Streptococcus pneumoniae (SPN) remains a major cause of morbidity and mortality worldwide, causing community-acquired pneumonia, meningitis, otitis media, sinusitis and bacteraemia. Here, we summarise an ethically approved protocol for a double-blind, randomised controlled trial investigating the effect of the 13-valent pneumococcal conjugate vaccine (PCV13) and the 23-valent pneumococcal polysaccharide vaccine (PPV23) on pneumococcal nasopharyngeal colonisation acquisition, density and duration using experimental human pneumococcal challenge (EHPC).

METHODS AND ANALYSIS

Healthy adult participants aged 18-50 years will be randomised to receive PCV13, PPV23 or placebo and then undergo one or two EHPCs involving intranasal administration of SPN at 1-month post-vaccination with serotype 3 (SPN3) and 6 months with serotype 6B (SPN6B). Participants randomised to PCV13 and placebo will also be randomised to one of two clinically relevant SPN3 strains from distinct lineages within clonal complex 180, clades Ia and II, creating five study groups. Following inoculation, participants will be seen on days 2, 7, 14 and 23. During the follow-up period, we will monitor safety, colonisation status, density and duration, immune responses and antigenuria. The primary outcome of the study is comparing the rate of SPN3 acquisition between the vaccinated (PCV13 or PPV23) and unvaccinated (placebo) groups as defined by classical culture. Density and duration of colonisation, comparison of acquisition rates using molecular methods and evaluation of the above measurements for individual SPN3 clades and SPN6B form the secondary objectives. Furthermore, we will explore the immune responses associated with these vaccines, their effect on colonisation and the relationship between colonisation and urinary pneumococcal antigen detection.

ETHICS AND DISSEMINATION

The study is approved by the NHS Research and Ethics Committee (Reference: 20/NW/0097) and by the Medicines and Healthcare products Regulatory Agency (Reference: CTA 25753/0001/001-0001). Findings will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ISRCTN15728847, NCT04974294.

Rates of Medically-Attended RSV among US Adults: A Systematic Review and Meta-Analysis

Background

Adult respiratory syncytial virus (RSV) vaccines are in late stages of development. A comprehensive synthesis of adult RSV burden is needed to inform public health decision-making.

Methods

We performed a systematic review and meta-analysis of studies describing the incidence of medically-attended RSV (MA-RSV) among US adults. We also identified studies reporting nasopharyngeal (NP) or nasal swab RT-PCR results with paired serology (four-fold-rise) or sputum (RT-PCR) to calculate RSV detection ratios quantifying improved diagnostic yield after adding a second specimen type (ie, serology or sputum).

Results

We identified 14 studies with 15 unique MA-RSV incidence estimates, all based on NP or nasal swab RT-PCR testing alone. Pooled annual RSV-associated incidence per 100,000 adults ≥65 years of age was 178 (95%CI: 152‒204; n = 8 estimates) hospitalizations (4 prospective studies: 189; 4 model-based studies: 157), 133 (95%CI: 0‒319, n = 2) emergency department (ED) admissions, and 1519 (95%CI: 1109‒1929, n = 3) outpatient visits. Based on 6 studies, RSV detection was ∼1.5 times higher when adding paired serology or sputum. After adjustment for this increased yield, annual RSV-associated rates per 100,000 adults ≥65 years were 267 hospitalizations (UI: 228‒306) (prospective: 282; model-based: 236), 200 ED admissions (UI: 0‒478), and 2278 outpatient visits (UI: 1663‒2893). Persons &lt;65 years with chronic medical conditions were 1.2−28 times more likely to be hospitalized for RSV depending on risk condition.

Conclusions

The true burden of RSV has been underestimated and is significant among older adults and individuals with chronic medical conditions. A highly effective adult RSV vaccine would have substantial public-health impact.

Pneumococcal serotypes in adults hospitalized with community-acquired pneumonia in Greece using urinary antigen detection tests: the EGNATIA study, November 2017 - April 2019

Greece introduced a 13-valent pneumococcal conjugate vaccine (PCV13) into the infant national immunization program in 2010 (3 + 1 schedule until June 2019). Since 2015, PCV13 has been recommended for adults aged 19-64 years with comorbidities and adults ≥65 years sequentially with 23-valent pneumococcal polysaccharide vaccine (PPSV23). We examined pneumococcal serotype distribution among Greek adults aged ≥19 years hospitalized with community-acquired pneumonia (CAP) during November 2017-April 2019. This was an interim analysis of EGNATIA, a prospective study of adult hospitalized CAP in the cities of Ioannina and Kavala. Pneumococcus was identified using cultures, BinaxNow®, serotype-specific urinary antigen detection assays (UAD-1/2). Our analysis included overall 482 hospitalized CAP patients (mean age: 70.5 years; 56.4% male). 53.53% of patients belonged to the highest pneumonia severity index (PSI) classes (IV-V). Pneumococcus was detected in 65 (13.5%) patients, with more than half (57%) of cases detected only by UAD. Approximately two-thirds of pneumococcal CAP occurred in those aged ≥65 years (n = 40, 8.3% of CAP). More than half of pneumococcal CAP (n = 35, 53.8%) was caused by PCV13 serotypes. Most frequently detected PCV13 serotypes were 3, 19A, 23F, collectively accounting for 83% of PCV13 vaccine-type (VT) CAP and 6% of all-cause CAP. Overall, 82.9% of PCV13 VT CAP occurred among persons with an indication (age/risk-based) for PCV13 vaccination. Even with a mature PCV13 childhood immunization program, a persistent burden of PCV13 VT CAP exists in Greek adults. Strategies to increase PCV13 (and higher-valency PCVs, when licensed) coverage in adults should be implemented to reduce the disease burden.

Incidence of acute lower respiratory tract disease hospitalisations, including pneumonia, among adults in Bristol, UK, 2019, estimated using both a prospective and retrospective methodology

OBJECTIVES

To determine the disease burden of acute lower respiratory tract disease (aLRTD) and its subsets (pneumonia, lower respiratory tract infection (LRTI) and heart failure) in hospitalised adults in Bristol, UK.

SETTING

Single-centre, secondary care hospital, Bristol, UK.

DESIGN

We estimated aLRTD hospitalisations incidence in adults (≥18 years) in Bristol, UK, using two approaches. First, retrospective International Classification of Diseases 10th revision (ICD-10) code analysis (first five positions/hospitalisation) identified aLRTD events over a 12-month period (March 2018 to February 2019). Second, during a 21-day prospective review (19 August 2019 to 9 September 2019), aLRTD admissions were identified, categorised by diagnosis and subsequently annualised. Hospital catchment denominators were calculated using linked general practice and hospitalisation data, with each practice's denominator contribution calculated based on practice population and per cent of the practices' hospitalisations admitted to the study hospital.

PARTICIPANTS

Prospective review: 1322 adults screened; 410 identified with aLRTD. Retrospective review: 7727 adult admissions.

PRIMARY AND SECONDARY OUTCOME MEASURES

The incidence of aLRTD and its subsets in the adult population of Southmead Hospital, Bristol UK.

RESULTS

Based on ICD-10 code analysis, annual incidences per 100 000 population were: aLRTD, 1901; pneumonia, 591; LRTI, 739; heart failure, 402. aLRTD incidence was highest among those ≥65 years: 65-74 (3684 per 100 000 adults), 75-84 (6962 per 100 000 adults) and ≥85 (11 430 per 100 000 adults). During the prospective review, 410/1322 (31%) hospitalised adults had aLRTD signs/symptoms and annualised incidences closely replicated retrospective analysis results.

CONCLUSIONS

The aLRTD disease burden was high, increasing sharply with age. The aLRTD incidence is probably higher than estimated previously due to criteria specifying respiratory-specific symptoms or radiological change, usage of only the first diagnosis code and mismatch between case count sources and population denominators. This may have significant consequences for healthcare planning, including usage of current and future vaccinations against respiratory infection.

Streptococcus pneumoniae colonization associates with impaired adaptive immune responses against SARS-CoV-2

Background

Although recent epidemiological data suggest that pneumococci may contribute to the risk of SARS-CoV-2 disease, cases of coinfection with Streptococcus pneumoniae in patients with coronavirus disease 2019 (COVID-19) during hospitalization have been reported infrequently. This apparent contradiction may be explained by interactions of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and pneumococci in the upper airway, resulting in the escape of SARS-CoV-2 from protective host immune responses.

Methods

Here, we investigated the relationship of these 2 respiratory pathogens in 2 distinct cohorts of health care workers with asymptomatic or mildly symptomatic SARS-CoV-2 infection identified by systematic screening and patients with moderate to severe disease who presented to the hospital. We assessed the effect of coinfection on host antibody, cellular, and inflammatory responses to the virus.

Results

In both cohorts, pneumococcal colonization was associated with diminished antiviral immune responses, which primarily affected mucosal IgA levels among individuals with mild or asymptomatic infection and cellular memory responses in infected patients.

Conclusion

Our findings suggest that S. pneumoniae impair host immunity to SARS-CoV-2 and raise the question of whether pneumococcal carriage also enables immune escape of other respiratory viruses and facilitates reinfection.

Trial registration

ISRCTN89159899 (FASTER study) and ClinicalTrials.gov NCT03502291 (LAIV study).

Epidemiology of Invasive Escherichia coli Infection and Antibiotic Resistance Status Among Patients Treated in US Hospitals: 2009-2016

BACKGROUND

Published data is limited on the prevalence and risk of recurrence of extraintestinal invasive Escherichia coli infections (IEIs) in the United States.

METHODS

The analysis included all inpatient and hospital-based outpatient visits occurring between 2009 and 2016 at hospitals with continuous microbiology data submission to the Premier Healthcare Database for 90 days before and 12 months after the admission or visit. IEI was defined as having positive E. coli culture from a normally sterile site (eg, blood, cerebrospinal fluid). The prevalence of IEI, 12-month risk of recurrent IEI, and antibiotic resistance were assessed.

RESULTS

Overall, 144 944 725 hospital visits among 37 207 510 patients were analyzed, and 71 909 IEI events occurred in 67 583 patients, corresponding to an IEI prevalence of 0.50 events per 1000 visits and 1.82 events per 1000 patients. Recurrence was common: 26.9 per 1000 patients had a recurrent IEI in the 12 months after their infection. Most infections were community acquired (66.4%), and urosepsis was most common clinical syndrome (66.0%). The 30-day risk of IEI among patients undergoing transrectal ultrasound-guided prostate biopsy was high: 5.03 events per 1000 patients. Among all IEI cases with antibiotic susceptibility testing, 9.18% were resistant to extended-spectrum cephalosporins, 28.22% to fluoroquinolones, and 0.14% to carbapenems. Resistance to extended-spectrum cephalosporins increased from 5.46% to 12.97% during the 8-year study period.

CONCLUSIONS

This real-world study indicates a substantial burden of IEI and recurrent IEI exists in the United States, as well as increasing resistance to extended-spectrum cephalosporins. Future research should explore risk factors of recurrent IEI aiming to effectively prevent such infections.

Invasive Staphylococcus aureus Infection among Patients Undergoing Elective, Posterior, Instrumented Spinal Fusion Surgeries: A Retrospective Cohort Study

Background: Post-surgical invasive Staphylococcus aureus infections among spinal fusion patients are serious complications that can worsen clinical outcomes and increase healthcare utilization. Risk of such infections at the population level remains unknown. This study assessed the post-surgical risk of invasive Staphylococcus aureus infections among patients undergoing elective posterior instrumented spinal fusion surgeries in 129 U.S. hospitals. Patients and Methods: This retrospective cohort study analyzed adult patients ≥18 years of age who underwent thoracolumbar/lumbar and cervical fusion surgeries during 2010 - 2014 using the Premier Healthcare Database, the largest hospital discharge database in the United States. Risks of blood stream infection (BSI), deep or organ/space surgical site infections (SSI) caused by Staphylococcus aureus during 90 and 180 days post-index surgery were estimated. Infections were identified based on positive culture results, related International Classification of Diseases, Ninth Revision (ICD-9) procedure codes, and specific claims information. Results: Among 11,236 patients with thoracolumbar/lumbar fusion, 90- and 180-day BSI/SSI infection risks were higher for multilevel than single level fusion (90-day, 1.52% vs. 1.07%, p = 0.05; 180-day, 1.66% vs. 1.07%, p = 0.014). Among 1,641 patients with cervical fusion, 90- and 180-day BSI/SSI infection risks were also higher in multilevel fusions but not statistically significant (90-day, 1.66% vs. 0.52%, p = 0.350; 180-day, 1.80% vs. 0.51%, p = 0.241). The risk for SSI/BSI was more than twice as high among multilevel thoracolumbar/lumbar fusion patients with more than two comorbidities than those with no comorbidity at both 90-day (2.78% vs. 1.00%, p < 0.05) and 180-day (3.01% vs. 1.10%, p < 0.05). Similar trend without statistical significance was seen in multilevel cervical fusion cohort (90-day, 2.91% vs. 1.25%, p > 0.05; 180-day, 3.88% vs. 1.41%, p > 0.05). Conclusions: The risk of BSI/SSI infection for elective posterior instrumented spinal fusions ranged between 0.5% and 2%. Higher risk was observed in multilevel thoracolumbar/lumbar surgery, with infection risk greatest in patients with more than two comorbidities. These real-world findings highlight the need for additional measures, in addition to antibiotic prophylaxis, to reduce invasive Staphylococcus aureus infections in this setting.

Fletcher M, Koki Ndombo P, Boula A, Ashukem NT, Ngo Baleba M, Kingue Bebey RS, Nkolo Mviena EG, Tageube J, Kobela Mbollo M, Koulla-Shiro S, Madhi S, Njanpop-Lafourcade BM, Mohammad A, Begier E, Southern J, Beavon R, Gessner B. Impact of 13-valent pneumococcal conjugate vaccine on laboratory-confirmed pneumococcal meningitis and purulent meningitis among children ˂5 years in Cameroon, 2011-2018

BACKGROUND

The 13-valent pneumococcal conjugate vaccine (PCV13) entered Cameroon's childhood national immunization programme (NIP) in July 2011 under a 3-dose schedule (6, 10, 14 weeks of age) without any catch-up. We described the impact of PCV13 onserotype distribution among pneumococcal meningitis cases over time.

METHODS

We used laboratory-based sentinel surveillance data to identify meningitis cases among 2- to 59-month-old children with clinically-suspected bacterial meningitis (CSBM) admitted to hospitals in Yaoundé (August 2011-December 2018). Purulent meningitis cases had a cerebrospinal fluid (CSF) white blood cell (WBC) count ≥20 per mm3. Pneumococcal meningitis cases had S. pneumoniae identified from CSF, with serotyping by polymerase chain reaction. Years 2011-2014 were described as early PCV13 era (EPE) and years 2015-2018 as late PCV13 era (LPE) impact periods.

RESULTS

Among children hospitalized with CSBM who had a lumbar puncture obtained, there was no significant change from the EPE versus the LPE in the percentage identified with purulent meningitis: 7.5% (112/1486) versus 9.4% (154/1645), p = 0.0846. The percentage of pneumococcal meningitis cases due to PCV13 vaccine-serotype (VST) decreased from 62.0% (31/50) during the EPE to 35.8% (19/53) in the LPE, p = 0.0081. The most frequent pneumococcal meningitis VSTs during the EPE were 6A/6B (30%) and 5 (6%), and during the LPE were 14 (13.2%), 3 (7.6%), 4 (5.6%) and 18C (5.6%).

CONCLUSION

Four to seven years after PCV13 introduction, the proportion of pneumococcal meningitis due to vaccine serotypes has declined, mainly due to reductions of serotypes 6A/6B, 1, 19A, and 23F; nevertheless, PCV13 VSTs remain common. Because the analyzed surveillance system was not consistent or population based, we could not estimate incidence or overall impact; this emphasizes the need for improved surveillance to document further the utility of PCV13 immunization in Cameroon.

The incidence of stroke among selected patients undergoing elective posterior lumbar fusion: a retrospective cohort study

BACKGROUND

Although stroke is a rare complication among spinal surgery patients, the recognition of this adverse event is critical given the aging population undergoing surgical procedures. The objective of this study was to estimate the incidence of stroke among selected adults undergoing elective posterior lumbar fusion (PLF) during various post-operative risk windows and among different subgroups.

METHODS

A retrospective cohort study using a longitudinal electronic healthcare record (EHR) database was conducted from January 1, 2007 to June 30, 2018. Elective PLF, stroke, and select clinical characteristics were defined based on International Classification of Disease codes. Patients aged 18 to 85 years with ≥183 days of enrollment in the database prior to undergoing elective PLF were followed from the index date until the occurrence of stroke, death, loss to follow-up, or end of study period, whichever occurred first. The incidence of stroke was estimated in the following risk windows: index hospitalization, ≤ 30 days, ≤ 90 days, ≤ 180 days, and ≤ 365 days post-operation.

RESULTS

A total of 43,063 patients were eligible for the study. The incidence of stroke following elective PLF was 0.29% (95% confidence interval [CI]: 0.25, 0.35%) during index hospitalization, 0.44% (95% CI: 0.38, 0.50%) ≤ 30 days, 0.59% (95% CI: 0.52, 0.67%) ≤ 90 days, 0.76% (95% CI: 0.68, 0.85%) ≤ 180 days, and 1.12% (95% CI: 1.03, 1.23%) ≤ 365 days post-operation. Stratified analyses revealed that older patients had a higher incidence of stroke. Additionally, black patients had higher stroke incidences. Post-operative stroke incidence was higher among patients with a history of type 2 diabetes than among patients without such history; similarly, stroke incidence was higher among patients with a history of stroke compared to patients without such history.

CONCLUSIONS

The incidence of stroke following elective PLF using an EHR database in this study is slightly higher than that reported in the literature. Our results suggest that stroke risk modification prior to PLF may be important for patients who are older, black, type 2 diabetic, and/or have a history of stroke.

Incidence of Staphylococcus aureus Infections After Elective Surgeries in US Hospitals

Background

Although Staphylococcus aureus is a leading cause of postsurgical infections, national estimates of these infections after elective surgeries based on microbiology data are limited. This study assessed cumulative 180-day postsurgical S. aureus incidence in real-world hospital settings.

Methods

A retrospective study of adults (≥18 years) undergoing inpatient or hospital-based outpatient elective surgeries from 1/7/2010–30/6/2015 at hospitals (N = 181) reporting microbiology results in the Premier Healthcare Database (PHD). 86 surgical categories were identified from the National Healthcare Safety Network procedures. We classified positive S. aureus cultures using a hierarchy (bloodstream [BSI], surgical site [SSI], and all other types [urinary tract, respiratory, other/unknown site]) and calculated incidence (number of infections divided by the number of elective surgery discharges). We estimated national infection case volumes by multiplying incidence by national inpatient elective surgical discharge estimates using the entire PHD and weights based on hospital characteristics.

Results

Following 884 803 inpatient elective surgical discharges, 180-day S. aureus infection incidence was 1.35% (0.30% BSI, 0.74% SSI no BSI, 0.32% all other types only). Among 1 116 994 hospital-based outpatient elective surgical discharges, 180-day S. aureus incidence was 1.19% (0.25% BSI, 0.75% SSI no BSI, 0.19% all other types only). Methicillin resistance was observed in ~45% of the S. aureus infections. We estimated 55 764 S. aureus postsurgical infections occurred annually in the US following 4.2 million elective inpatient surgical discharges.

Conclusions

The high burden of S. aureus infections after both inpatient and outpatient elective surgeries highlights the continued need for surveillance and novel infection prevention efforts.

Culture-Confirmed Staphylococcus aureus Infection after Elective Hysterectomy: Burden of Disease and Risk Factors

Background: Our study sought to describe the incidence of culture-confirmed postsurgical Staphylococcus aureus infection after elective hysterectomy and evaluate patient characteristics, risk factors, and economic consequences associated with Staphylococcus aureus infection. Methods: This was a retrospective cohort study of patients in the United States (≥18 years old; Kaiser Permanente health plan members) who underwent elective hysterectomy from 2007 to 2013. Hysterectomies were categorized by surgical setting (inpatient vs. outpatient) and procedure (abdominal, laparoscopic, or vaginal). We estimated the cumulative incidence of culture-confirmed Staphylococcus aureus infection (90 days post-surgery) and compared healthcare resource utilization and costs (within 120 days post-surgery) among patients with/without Staphylococcus aureus infection or with other infection. Results: Among 30,960 patients identified, 20,675 underwent inpatient hysterectomy (abdominal: 47.8%; laparoscopic: 24.8%; vaginal: 27.3%), and 10,285 underwent outpatient hysterectomy (laparoscopic: 86.1%; vaginal: 13.9%). The incidence of culture-confirmed Staphylococcus aureus infection was 0.8% and 0.4% for inpatient (abdominal: 1.2%; laparoscopic: 0.5%; vaginal: 0.2%) and outpatient (laparoscopic: 0.5%; vaginal: 0.1%) surgery, respectively. Patients with Staphylococcus aureus infection had more emergency department visits, hospitalizations, and re-operations compared with patients without infection or with non-Staphylococcus aureus infection. Mean total costs for patients with Staphylococcus aureus infection were higher (inpatient: $18,261; outpatient: $4,422) compared with patients without infection (inpatient: $6,171; p < 0.0001; outpatient: $905; p = 0.0023) or non-Staphylococcus aureus infection (inpatient: $11,207; p = 0.0117; outpatient: $3,005; p = 0.2117). Conclusions: Culture-confirmed postsurgical Staphylococcus aureus infection incidence was predominately associated with procedure type rather than surgical setting. Patients with post-surgical Staphylococcus aureus infection had higher health care utilization and costs than those without infection or with other infection types. Additional effective infection control strategies are needed to reduce the morbidity and costs associated with Staphylococcus aureus infection.