Respiratory Syncytial Virus Sequelae Among Adults in High-Income Countries: A Systematic Literature Review and Meta-analysis

INTRODUCTION

Respiratory syncytial virus (RSV) can cause severe respiratory infections in adults; however, information on associated sequelae is limited. This systematic literature review aimed to identify sequelae in adults within 1 year following RSV-related hospitalization or resolution of acute infection.

METHODS

Studies were identified from Embase, MEDLINE, LILACS, SciELO, and grey literature. Random-effects meta-analyses using restricted maximum likelihood were used to calculate the proportions and relative risks of sequelae in patients with RSV compared with controls (patients with RSV-negative influenza-like illness, influenza, and parainfluenza) per follow-up period, population, and treatment setting, where possible.

RESULTS

Twenty-one relevant studies covering the period from 1990 to 2019 were included. Among the general population, the most frequent clinical sequela was sustained function loss (33.5% [95% CI 27.6-39.9]). Decline in lung function and cardiovascular event or congestive heart failure were also identified. Utilization sequelae were readmission (highest at > 6 months after discharge) and placement in a skilled nursing facility. The only subpopulation with data regarding sequelae was transplant patients. Among lung transplant patients, the most frequently reported clinical sequelae were decline in lung function, followed by graft dysfunction and bronchiolitis obliterans syndrome. Pooled relative risks were calculated for the following sequela with controls (primarily influenza-positive patients): cardiovascular event (general population) and pulmonary impairment (hematogenic-transplant patients) both 1.4 (95% CI 1.0-2.0) and for readmission (general population) 1.2 (95% CI 1.1-1.3).

CONCLUSIONS

Although less data are available for RSV than for influenza or other lower respiratory tract infections, RSV infection among adults is associated with medically important sequelae, with a prevalence similar to other respiratory pathogens. RSV sequelae should be included in disease burden estimates.

Influenza Vaccine Effectiveness Pre-pandemic Among Adults Hospitalized With Congestive Heart Failure or Chronic Obstructive Pulmonary Disease and Older Adults

BACKGROUND

Data are limited on influenza vaccine effectiveness (VE) in the prevention of influenza-related hospitalizations in older adults and those with underlying high-risk comorbidities.

METHODS

We conducted a prospective, test-negative, case-control study at 2 US hospitals from October 2018-March 2020 among adults aged ≥50 years hospitalized with acute respiratory illnesses (ARIs) and adults ≥18 years admitted with congestive heart failure (CHF) or chronic obstructive pulmonary disease (COPD) exacerbations. Adults were eligible if they resided in 1 of 8 counties in metropolitan Atlanta, Georgia. Nasopharyngeal and oropharyngeal swabs were tested using BioFire FilmArray (bioMérieux, Inc.) respiratory panel, and standard-of-care molecular results were included when available. Influenza vaccination history was determined from the Georgia vaccine registry and medical records. We used multivariable logistic regression to control for potential confounders and to determine 95% confidence intervals (CIs).

RESULTS

Among 3090 eligible adults, 1562 (50.6%) were enrolled. Of the 1515 with influenza vaccination history available, 701 (46.2%) had received vaccination during that season. Influenza was identified in 37 (5.3%) vaccinated versus 78 (9.6%) unvaccinated participants. After adjustment for age, race/ethnicity, immunosuppression, month, and season, pooled VE for any influenza-related hospitalization in the eligible study population was 63.1% (95% CI, 43.8-75.8%). Adjusted VE against influenza-related hospitalization for ARI in adults ≥50 years was 55.9% (29.9-72.3%) and adjusted VE against influenza-related CHF/COPD exacerbation in adults ≥18 years was 80.3% (36.3-93.9%).

CONCLUSIONS

Influenza vaccination was effective in preventing influenza-related hospitalizations in adults aged ≥50 years and those with CHF/COPD exacerbations during the 2018-2020 seasons.

Best Practices for Identifying Hospitalized Lower Respiratory Tract Infections Using Administrative Data: A Systematic Literature Review of Validation Studies

INTRODUCTION

Estimating the burden of lower respiratory tract infections (LRTIs) increasingly relies on administrative databases using International Classification of Diseases (ICD) codes, but no standard methodology exists. We defined best practices for ICD-based algorithms that estimate LRTI incidence in adults.

METHODS

We conducted a systematic review of validation studies assessing the use of ICD code-based algorithms to identify hospitalized LRTIs in adults, published in Medline, EMBASE, and LILACS between January 1996 and January 2022, according to PRISMA guidelines. We assessed sensitivity, specificity, and other accuracy measures of different algorithms.

RESULTS

We included 26 publications that used a variety of ICD code-based algorithms and gold standard criteria, and 18 reported sensitivity and/or specificity. Sensitivity was below 80% in 72% (38/53) of algorithms and specificity exceeded 90% in 77% (37/48). Algorithms for all-cause LRTI (n = 18) that included only pneumonia codes in primary position (n = 3) had specificity greater than 90% but low sensitivity (55-72%). Sensitivity increased by 5-15%, with minimal loss in specificity, with the addition of primary codes for severe pneumonia (e.g. sepsis) while pneumonia codes were in secondary position, and by 13% with codes from LRTI-related infections (e.g. viral) or other respiratory diseases (e.g. empyema). Sensitivity increased by 8% when pneumonia codes were in any position, but specificity was not reported. In hospital-acquired pneumonia and pneumococcal-specific pneumonia, algorithms containing only nosocomial- or pathogen-specific ICD codes had poor sensitivity, which improved when broader pneumonia codes were added, in particular codes for unspecified organisms.

CONCLUSION

Our systematic review highlights that most ICD code-based algorithms are relatively specific, but miss a substantial number of hospitalized LRTI adult cases. Best practices to estimate LRTI incidence in this population include the use of all pneumonia ICD codes for any LRTI outcome and, to a lesser extent, those for other LRTI-related infections or respiratory diseases.

Estimation of Symptomatic Respiratory Syncytial Virus Infection Incidence in Adults in Multiple Countries: A Time-Series Model-Based Analysis Protocol

INTRODUCTION

Estimating respiratory syncytial virus (RSV) burden in adults is challenging because of non-specific symptoms, infrequent standard-of-care testing, resolution of viral shedding before seeking medical care, test positivity that varies by specimen site in the upper airway and lower diagnostic test sensitivity compared to children. Conducting prospective observational studies to assess RSV burden in adults is time- and resource-intensive. Thus, model-based approaches can be applied using existing data to obtain more accurate estimates of RSV burden. This protocol establishes essential elements for estimating RSV incidence rate in adults using a time series model-based approach. It can be tailored to specific databases and applied globally across countries, enabling estimation of local RSV disease burden to inform public health decision-making, including immunization policy.

METHODS

Data are analysed using a quasi-Poisson regression model, considering the effect of baseline trends and pathogen co-circulation, stratified by age and risk status. Pathogen co-circulation is represented by viral proxies defined based on ICD code groupings indicating RSV and influenza-specific hospitalizations, lagged 0 up to 4 weeks based on the model selection. A final model is constructed in two steps: optimization of the time trend (using p-values) and selection of the viral proxy lag time (using test statistics, to prioritize the most biologically plausible option). The yearly incidence rate and percentage of events attributable to RSV are estimated from the final model. Confidence intervals are calculated using residual bootstrapping.

PLANNED OUTCOMES

Outcomes to be modelled are based on administrative ICD code groupings and include the number of cardiorespiratory, respiratory and cardiovascular events in a specific care setting (e.g., general practitioner visit, emergency department visit, hospitalization and death). Cardiovascular events are limited to those for which existing evidence suggests an association with RSV infection. Additional secondary outcomes are constructed as a subset of the primary outcomes based on specific ICD code groups.

Estimated Incidence of Hospitalizations and Deaths Attributable to Respiratory Syncytial Virus Infections Among Adults in Germany Between 2015 and 2019

INTRODUCTION

Respiratory syncytial virus (RSV) burden in adults is underestimated mainly due to unspecific symptoms and limited standard-of-care testing. We estimated the population-based incidence of hospitalization and mortality attributable to RSV among adults with and without risk factors in Germany.

METHODS

Weekly counts of hospitalizations and deaths for respiratory, cardiovascular, and cardiorespiratory diseases were obtained (Statutory Health Insurance database, 2015-2019). A quasi-Poisson regression model was fitted to estimate the number of hospitalizations and deaths attributable to RSV as a function of periodic and aperiodic time trends, and viral activity while allowing for potential overdispersion. Weekly counts of RSV and influenza hospitalizations in children < 2 years and adults ≥ 60 years, respectively, were used as viral activity indicators. Models were stratified by age group and risk status (defined as presence of selected comorbidities).

RESULTS

Population-based RSV-attributable hospitalization incidence rates were high among adults ≥ 60 years: respiratory hospitalizations (236-363 per 100,000 person-years) and cardiorespiratory hospitalizations (584-912 per 100,000 person-years). RSV accounted for 2-3% of all cardiorespiratory hospitalizations in this age group. The increase in cardiorespiratory hospitalization risk associated with underlying risk factors was greater in 18-44 year old persons (five to sixfold higher) than in ≥ 75 year old persons (two to threefold higher).

CONCLUSIONS

This is a first model-based study to comprehensively assess adult RSV burden in Germany. Estimated cardiorespiratory RSV hospitalization rates increased with age and were substantially higher in people with risk factors compared to those without risk factors. Our study indicates that RSV, like other respiratory viruses, contributes to both respiratory and cardiovascular hospitalizations. Effective prevention strategies are needed, especially among older adults ≥ 60 years and among adults with underlying risk factors.

Surveillance of pneumococcal serotypes in adults hospitalised with acute lower respiratory tract infection in Bristol, UK

INTRODUCTION

Pneumococcus remains a major cause of adult lower respiratory tract infections (LRTI). Few data exist on the relative contribution of serotypes included in pneumococcal vaccines to community-acquired pneumonia (CAP) and non-pneumonic (NP) LRTI. We measured the burden of all and vaccine-serotype pneumococcal respiratory infection following SARS-CoV-2 emergence to inform evidence-based vaccination policy.

METHODS

A prospective cohort study at two Bristol hospitals (UK) including all adults age ≥ 18-years hospitalised with acute lower respiratory tract disease (aLRTD) from Nov2021-Nov2022. LRTI patients were classified as: a) radiographically-confirmed CAP (CAP+/RAD+), b) clinically-diagnosed CAP without radiological confirmation (CAP+/RAD-), or c) NP-LRTI. Pneumococcus was identified by blood culture, BinaxNOW™and serotype-specific urine antigen detection assays (UAD).

RESULTS

Of 12,083 aLRTD admissions, 10,026 had LRTI and 2,445 provided urine: 1,097 CAP + RAD+; 207 CAP + RAD-; and 1,141 NP-LRTI. Median age was 71.1y (IQR57.9-80.2) and Charlson comorbidity index = 4 (IQR2-5); 2.7 % of patients required intensive care, and 4.4 % died within 30-days of hospitalisation. Pneumococcus was detected in 280/2445 (11.5 %) participants. Among adults aged ≥ 65y and 18-64y, 12.9 % (198/1534) and 9.0 % (82/911), respectively, tested pneumococcus positive. We identified pneumococcus in 165/1097 (15.0 %) CAP + RAD+, 23/207 (11.1 %) CAP + RAD-, and 92/1141 (8.1 %) NP-LRTI cases. Of the 280 pneumococcal cases, 102 (36.4 %) were due to serotypes included in PCV13 + 6C, 115 (41.7 %) in PCV15 + 6C, 210 (75.0 %) in PCV20 + 6C/15C and 228 (81.4 %) in PPV23 + 15C. The most frequently identified serotypes were 8 (n = 78; 27.9 % of all pneumococcus), 7F (n = 25; 8.9 %), and 3 (n = 24; 8.6 %).

DISCUSSION

Among adults hospitalised with respiratory infection, pneumococcus is an important pathogen across all subgroups, including CAP+/RAD- and NP-LRTI. Despite 20-years of PPV23 use in adults ≥ 65-years and herd protection due to 17-years of PCV use in infants, vaccine-serotype pneumococcal disease still causes a significant proportion of LRTI adult hospitalizations. Direct adult vaccination with high-valency PCVs may reduce pneumococcal disease burden.

Attributable Cost of Adult Respiratory Syncytial Virus Illness Beyond the Acute Phase

Background

Estimates of the cost of medically attended lower respiratory tract illness (LRTI) due to respiratory syncytial virus (RSV) in adults, especially beyond the acute phase, is limited. This study was undertaken to estimate the attributable costs of RSV-LRTI among US adults during, and up to 1 year after, the acute phase of illness.

Methods

A retrospective observational matched-cohort design and a US healthcare claims repository (2016-2019) were employed. The study population comprised adults aged ≥18 years with RSV-LRTI requiring hospitalization (RSV-H), an emergency department visit (RSV-ED), or physician office/hospital outpatient visit (RSV-PO/HO), as well as matched comparison patients. All-cause healthcare expenditures were tallied during the acute phase of illness (RSV-H: from admission through 30 days postdischarge; ambulatory RSV: during the episode) and long-term phase (end of acute phase to end of following 1-year period).

Results

The study population included 4526 matched pairs of RSV-LRTI and comparison patients (RSV-H: n = 970; RSV-ED: n = 590; RSV-PO/HO: n = 2966). Mean acute-phase expenditures were $42 179 for RSV-H (vs $5154 for comparison patients), $4409 for RSV-ED (vs $377), and $922 for RSV-PO/HO (vs $201). By the end of the 1-year follow-up period, mean expenditures-including acute and long-term phases-were $101 532 for RSV-H (vs $36 302), $48 701 for RSV-ED (vs $27 131), and $28 851 for RSV-PO/HO (vs $20 523); overall RSV-LRTI attributable expenditures thus totaled $65 230, $21 570, and $8327, respectively.

Conclusions

The cost of RSV-LRTI requiring hospitalization or ambulatory care among US adults is substantial, and the economic impact of RSV-LTRI may extend well beyond the acute phase of illness.

Effectiveness of Vaccines and Monoclonal Antibodies Against Respiratory Syncytial Virus: Generic Protocol for Register-Based Cohort Study

Several immunization products are currently being developed against respiratory syncytial virus (RSV) for children, pregnant females, and older adults, and some products have already received authorization. Therefore, studies to monitor the effectiveness of these products are needed in the following years. To assist researchers to conduct postmarketing studies, we developed a generic protocol for register-based cohort studies to evaluate immunization product effectiveness against RSV-specific and nonspecific outcomes. To conduct a study on the basis of this generic protocol, the researchers can use any relevant databases or healthcare registers that are available at the study site.

Estimated Respiratory Syncytial Virus-Related Hospitalizations and Deaths Among Children and Adults in Spain, 2016-2019

INTRODUCTION

Respiratory syncytial virus (RSV) causes a substantial disease burden among infants. In older children and adults, incidence is underestimated due to nonspecific symptoms and limited standard-of-care testing. We aimed to estimate RSV-attributable hospitalizations and deaths in Spain during 2016-2019.

METHODS

Nationally representative hospitalization and mortality databases were obtained from the Ministry of Health and the National Statistical Office. A quasi-Poisson regression model was fitted to estimate the number of hospitalizations and deaths attributable to RSV as a function of periodic and aperiodic time trends and viral activity, while allowing for potential overdispersion.

RESULTS

In children, the RSV-attributable respiratory hospitalization incidence was highest among infants aged 0-5 months (3998-5453 cases/100,000 person-years, representing 72% of all respiratory hospitalizations) and decreased with age. In 2019, estimated rates in children 0-5, 6-11, 12-23 months and 6-17 years were approximately 1.3, 1.4, 1.5, and 6.5 times higher than those based on standard-of-care RSV-specific codes. In adults, the RSV-attributable cardiorespiratory hospitalization rate increased with age and was highest among persons ≥ 80 years (1325-1506 cases/100,000, 6.5% of all cardiorespiratory hospitalizations). In 2019, for persons aged 18-49, 50-59, 60-79, and ≥ 80 years, estimated rates were approximately 8, 6, 8, and 16 times higher than those based on standard-of-care RSV-specific codes. The RSV-attributable cardiorespiratory mortality rate was highest among ≥ 80 age group (126-150 deaths/100,000, 3.5-4.1% of all cardiorespiratory deaths), when reported mortality rate ranged between 0 and 0.5/100,000.

CONCLUSIONS

When accounting for under-ascertainment, estimated RSV-attributable hospitalizations were higher than those reported based on standard-of-care RSV-specific codes in all age groups but particularly among older children and older adults. Like other respiratory viruses, RSV contributes to both respiratory and cardiovascular complications. Efficacious RSV vaccines could have a high public health impact in these age and risk groups.

Effectiveness of Immunization Products Against Medically Attended Respiratory Syncytial Virus Infection: Generic Protocol for a Test-Negative Case-Control Study

Monitoring the real-life effectiveness of respiratory syncytial virus (RSV) products is of major public health importance. This generic protocol for a test-negative design study aims to address currently envisioned approaches for RSV prevention (monoclonal antibodies and vaccines) to study effectiveness of these products among target groups: children, older adults, and pregnant women. The generic protocol approach was chosen to allow for flexibility in adapting the protocol to a specific setting. This protocol includes severe acute respiratory infection (SARI) and acute respiratory infection (ARI), both due to RSV, as end points. These end points can be applied to studies in hospitals, primarily targeting patients with more severe disease, but also to studies in general practitioner clinics targeting ARI.

Multicountry Review of Streptococcus pneumoniae Serotype Distribution Among Adults With Community-Acquired Pneumonia

BACKGROUND

Nonbacteremic community-acquired pneumonia (CAP) is a leading presentation of severe pneumococcal disease in adults. Serotype-specific urinary antigen detection (UAD) assay can detect serotypes causing pneumococcal CAP, including nonbacteremic cases, and guide recommendations for use of higher valency pneumococcal conjugate vaccines (PCVs).

METHODS

Adult CAP serotype distribution studies that used both Pfizer UADs (UAD1, detects PCV13 serotypes; UAD2, detects PCV20 non-PCV13 serotypes plus 2, 9N, 17F, and 20) were identified by review of an internal study database and included if results were published. The percentages of all-cause radiologically confirmed CAP (RAD + CAP) due to individual or grouped (PCV13, PCV15, and PCV20) serotypes as detected from culture or UAD were reported.

RESULTS

Six studies (n = 2, United States; n = 1 each, Germany, Sweden, Spain, and Greece) were included. The percentage of RAD + CAP among adults ≥18 years with PCV13 serotypes equaled 4.6% to 12.9%, with PCV15 serotypes 5.9% to 14.5%, and with PCV20 serotypes 7.8% to 23.8%. The percentage of RAD + CAP due to PCV15 and PCV20 serotypes was 1.1-1.3 and 1.3-1.8 times higher than PCV13 serotypes, respectively.

CONCLUSIONS

PCV13 serotypes remain a cause of RAD + CAP among adults even in settings with pediatric PCV use. Higher valency PCVs among adults could address an important proportion of RAD + CAP in this population.

Rates of Lower Respiratory Tract Illness in US Adults by Age and Comorbidity Profile

INTRODUCTION

While it is widely recognized that older adults, adults with chronic medical conditions (CMC), and adults with immunocompromising conditions (IC) are at increased risk of lower respiratory tract illness (LRTI), evidence of the magnitude of increased risk is limited. This study was thus undertaken to characterize rates of hospitalized and ambulatory LRTI among United States (US) adults by age and comorbidity profile.

METHODS

A retrospective cohort design and US healthcare claims database (2016-2019) were employed. Study population included adults aged ≥ 18 years and was stratified by age and comorbidity profile (CMC-, CMC+ , IC). LRTI was ascertained overall and by pathogen pathogen (e.g., respiratory syncytial virus [RSV]), and was classified by care setting (hospital, emergency department [ED], physician office/hospital outpatient [PO/HO]).

RESULTS

Relative rates (RR) of LRTI generally increased with older age across care settings (vs. 18-49 years), with the most marked increase for hospitalizations: for LRTI-hospitalized, RRs ranged from 3.3 for 50-64 years to 46.6 for ≥ 85 years; for LRTI-ED and LRTI-PO/HO, RRs ranged from 1.0 to 2.7 and from 1.3 to 1.5, respectively. Within age groups, LRTI rates were also consistently higher among CMC+ and IC adults (vs. CMC- adults). Age-specific RRs of LRTI patients hospitalized due to RSV were largely comparable to overall LRTI; age-specific RRs for other care settings, and RRs for CMC+ and IC adults (vs. CMC- adults), were generally higher for LRTI due to RSV.

CONCLUSIONS

Incidence of LRTI, including that due to RSV, especially for events requiring acute inpatient care, is markedly higher among older adults and adults of all ages with CMC or IC.

Prospective incidence epidemiology study protocol: conducting active surveillance to assess the burden of Lyme disease (BOLD) in primary care practices in endemic areas of six European countries

INTRODUCTION

Lyme disease (LD) is the most frequent tick-borne disease in the moderate climates of Europe. This study will inform the phase III efficacy study for Pfizer and Valneva's investigational Lyme disease vaccine, VLA15. VLA15 phase III will be conducted in the USA and Europe due to the vaccine's serotype coverage and public health burden of LD. In Europe, the existence and location of sites that have access to populations with high LD annual incidence is uncertain. This active, prospective surveillance study assesses annual LD incidence at general practice (GP)/primary care sites, allowing for phase III site vetting and better characterisation of LD burden in selected regions for study size calculations.

METHODS AND ANALYSIS

This burden of Lyme disease (BOLD) study will assess LD incidence overall and by site at 15 GP/primary care practices in endemic areas of 6 European countries from Spring 2021 to December 2022 and will be summarised with counts (n), percentages (%) and associated 95% CIs. Suspected LD cases identified from site's practice panels are documented on screening logs, where clinical LD manifestations, diagnoses and standard of care diagnostic results are recorded. In the initial 12-month enrolment phase, suspected LD cases are offered enrolment. Participants undergo interview and clinical assessments to establish medical history, final clinical diagnosis, clinical manifestations and quality of life impact. Study-specific procedures include LD serology, skin punch biopsies and Lyme manifestation photographs. For every enrolled participant diagnosed with LD, 6-10 age-matched controls are randomly selected and offered enrolment for an embedded LD risk factor analysis. Persistent symptoms or post-treatment LD will be assessed at follow-up visits up to 2 years after initial diagnosis, while patients remain symptomatic.

ETHICS AND DISSEMINATION

This study has been approved by all sites' local ethics committees. The results will be presented at conferences and published in peer-reviewed journals.

Pediatric Respiratory Syncytial Virus Diagnostic Testing Performance: A Systematic Review and Meta-analysis

BACKGROUND

Adding additional specimen types (eg, serology or sputum) to nasopharyngeal swab (NPS) reverse transcription polymerase chain reaction (RT-PCR) increases respiratory syncytial virus (RSV) detection among adults. We assessed if a similar increase occurs in children and quantified underascertainment associated with diagnostic testing.

METHODS

We searched databases for studies involving RSV detection in persons <18 years using ≥2 specimen types or tests. We assessed study quality using a validated checklist. We pooled detection rates by specimen and diagnostic tests and quantified performance.

RESULTS

We included 157 studies. Added testing of additional specimens to NP aspirate (NPA), NPS, and/or nasal swab (NS) RT-PCR resulted in statistically nonsignificant increases in RSV detection. Adding paired serology testing increased RSV detection by 10%, NS by 8%, oropharyngeal swabs by 5%, and NPS by 1%. Compared to RT-PCR, direct fluorescence antibody tests, viral culture, and rapid antigen tests were 87%, 76%, and 74% sensitive, respectively (pooled specificities all ≥98%). Pooled sensitivity of multiplex versus singleplex RT-PCR was 96%.

CONCLUSIONS

RT-PCR was the most sensitive pediatric RSV diagnostic test. Adding multiple specimens did not substantially increase RSV detection, but even small proportional increases could result in meaningful changes in burden estimates. The synergistic effect of adding multiple specimens should be evaluated.

Systematic Literature Review of Risk Factors for Poor Outcomes Among Adults With Respiratory Syncytial Virus Infection in High-Income Countries

Identification of risk factors for severe respiratory syncytial virus (RSV) disease in adults could facilitate their appropriate vaccine recommendations. We conducted a systematic literature review (last 10 years in PubMed/Embase) to identify quantitative estimates of risk factors for severe RSV infection outcomes in high-income countries. Severe outcomes from RSV infection included hospitalization, excess mortality, lower respiratory tract infection, or a composite measure: severe RSV, which included these outcomes and others, such as mechanical ventilation and extended hospital stay. Among 1494 articles screened, 26 met eligibility criteria. We found strong evidence that the following increased the risk of severe outcomes: age, preexisting comorbid conditions (eg, cardiac, pulmonary, and immunocompromising diseases, as well as diabetes and kidney disease), and living conditions (socioeconomic status and nursing home residence). The frequency of severe outcomes among younger adults with comorbidities was generally similar to that experienced by older adults, suggesting that immunosenescence and chronic conditions are both contributing factors for elevated risk.

Trial registration

PROSPERO (CRD42022315239).

Impact of SARS-CoV-2 infective exacerbation of chronic obstructive pulmonary disease on clinical outcomes in a prospective cohort study of hospitalised adults

OBJECTIVES

To determine whether acute exacerbations of chronic obstructive pulmonary disease (AECOPD) triggered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have worse outcomes than AECOPD caused by other infectious agents or non-infective AECOPD (NI-COPD).

DESIGN

A two-hospital prospective cohort study of adults hospitalised with acute respiratory disease. We compared outcomes with AECOPD and a positive test for SARS-CoV-2 (n = 816), AECOPD triggered by other infections (n = 3038) and NI-COPD (n = 994). We used multivariable modelling to adjust for potential confounders and assessed variation by seasons associated with different SARS-CoV-2 variants.

SETTING

Bristol UK, August 2020-May 2022.

PARTICIPANTS

Adults (≥18 y) hospitalised with AECOPD.

MAIN OUTCOME MEASURES

We determined the risk of positive pressure support, longer hospital admission and mortality following hospitalisation with AECOPD due to non-SARS-CoV-2 infection compared with SARS-CoV-2 AECOPD and NI-COPD.

RESULTS

Patients with SARS-CoV-2 AECOPD, in comparison to non-SARS-CoV-2 infective AECOPD or NI-COPD, more frequently required positive pressure support (18.5% and 7.5% vs. 11.7%, respectively), longer hospital stays (median [interquartile range, IQR]: 7 [3-15] and 5 [2-10] vs. 4 [2-9] days, respectively) and had higher 30-day mortality (16.9% and 11.1% vs. 5.9%, respectively) (all p < 0.001). In adjusted analyses, SARS-CoV-2 AECOPD was associated with a 55% (95% confidence interval [95% CI]: 24-93), 26% (95% CI: 15-37) and 35% (95% CI: 10-65) increase in the risk of positive pressure support, hospitalisation length and 30-day mortality, respectively, relative to non-SARS-CoV-2 infective AECOPD. The difference in risk remained similar during periods of wild-type, Alpha and Delta SARS-CoV-2 strain dominance, but diminished during Omicron dominance.

CONCLUSIONS

SARS-CoV-2-related AECOPD had worse patient outcomes compared with non-SARS-CoV-2 AECOPD or NI-AECOPD, although the difference in risks was less pronounced during Omicron dominance.

Underascertainment of Respiratory Syncytial Virus Infection in Adults Due to Diagnostic Testing Limitations: A Systematic Literature Review and Meta-analysis

BACKGROUND

Most observational population-based studies identify respiratory syncytial virus (RSV) by nasal/nasopharyngeal swab reverse transcriptase real-time PCR (RT-PCR) only. We conducted a systematic review and meta-analyses to quantify specimen and diagnostic testing-based underascertainment of adult RSV infection.

METHODS

EMBASE, PubMed, and Web of Science were searched (January 2000-December 2021) for studies including adults using/comparing >1 RSV testing approach. We quantified test performance and RSV detection increase associated with using multiple specimen types.

RESULTS

Among 8066 references identified, 154 met inclusion. Compared to RT-PCR, other methods were less sensitive: rapid antigen detection test (RADT; pooled sensitivity, 64%), direct fluorescent antibody (DFA; 83%), and viral culture (86%). Compared to singleplex PCR, multiplex PCR's sensitivity was lower (93%). Compared to nasal/nasopharyngeal swab RT-PCR alone, adding another specimen type increased detection: sputum RT-PCR, 52%; 4-fold rise in paired serology, 44%; and oropharyngeal swab RT-PCR, 28%. Sensitivity was lower in estimates limited to only adults (for RADT, DFA, and viral culture), and detection rate increases were largely comparable.

CONCLUSIONS

RT-PCR, particularly singleplex testing, is the most sensitive RSV diagnostic test in adults. Adding additional specimen types to nasopharyngeal swab RT-PCR testing increased RSV detection. Synergistic effects of using ≥3 specimen types should be assessed, as this approach may improve the accuracy of adult RSV burden estimates.

Incidence of Respiratory Syncytial Virus Infection in Older Adults: Limitations of Current Data

INTRODUCTION

Respiratory syncytial virus (RSV) is an important cause of severe respiratory illness in older adults and adults with respiratory or cardiovascular comorbidities. Published estimates of its incidence and prevalence in adult groups vary widely. This article reviews the potential limitations affecting RSV epidemiology studies and suggests points to consider when evaluating or designing them.

METHODS

Studies reporting the incidence or prevalence of RSV infection in adults in high-income Western countries from 2000 onwards were identified via a rapid literature review. Author-reported limitations were recorded, together with presence of other potential limitations. Data were synthesized narratively, with a focus on factors affecting incidence estimates for symptomatic infection in older adults.

RESULTS

A total of 71 studies met the inclusion criteria, most in populations with medically attended acute respiratory illness (ARI). Only a minority used case definitions and sampling periods tailored specifically to RSV; many used influenza-based or other criteria that are likely to result in RSV cases being missed. The great majority relied solely on polymerase chain reaction (PCR) testing of upper respiratory tract samples, which is likely to miss RSV cases compared with dual site sampling and/or addition of serology. Other common limitations were studying a single season, which has potential for bias due to seasonal variability; failure to stratify results by age, which underestimates the burden of severe disease in older adults; limited generalizability beyond a limited study setting; and absence of measures of uncertainty in the reporting of results.

CONCLUSIONS

A significant proportion of studies are likely to underestimate the incidence of RSV infection in older adults, although the effect size is unclear and there is also potential for overestimation. Well-designed studies, together with increased testing for RSV in patients with ARI in clinical practice, are required to accurately capture both the burden of RSV and the potential public health impact of vaccines.

Diagnosis of Respiratory Syncytial Virus in Adults Substantially Increases When Adding Sputum, Saliva, and Serology Testing to Nasopharyngeal Swab RT-PCR

INTRODUCTION

Nearly all existing respiratory syncytial virus (RSV) incidence estimates are based on real-time polymerase chain reaction (RT-PCR) testing of nasal or nasopharyngeal (NP) swabs. Adding testing of additional specimen types to NP swab RT-PCR increases RSV detection. However, prior studies only made pairwise comparisons and the synergistic effect of adding multiple specimen types has not been quantified. We compared RSV diagnosis by NP swab RT-PCR alone versus NP swab plus saliva, sputum, and serology.

METHODS

This was a prospective cohort study over two study periods (27 December 2021 to 1 April 2022 and 22 August 2022 to 11 November 2022) of patients aged ≥ 40 years hospitalized for acute respiratory illness (ARI) in Louisville, KY. NP swab, saliva, and sputum specimens were collected at enrollment and PCR tested (Luminex ARIES platform). Serology specimens were obtained at acute and convalescent timepoints (enrollment and 30-60-day visit). RSV detection rate was calculated for NP swab alone and for NP swab plus all other specimen type/test.

RESULTS

Among 1766 patients enrolled, 100% had NP swab, 99% saliva, 34% sputum, and 21% paired serology specimens. RSV was diagnosed in 56 (3.2%) patients by NP swab alone, and in 109 (6.2%) patients by NP swab plus additional specimens, corresponding to a 1.95 times higher rate [95% confidence interval (CI) 1.62, 2.34]. Limiting the comparison to the 150 subjects with all four specimen types available (i.e., NP swab, saliva, sputum, and serology), there was a 2.60-fold increase (95% CI 1.31, 5.17) compared to NP swab alone (3.3% versus 8.7%). Sensitivities by specimen type were: NP swab 51%, saliva 70%, sputum 72%, and serology 79%.

CONCLUSIONS

Diagnosis of RSV in adults was several-fold greater when additional specimen types were added to NP swab, even with a relatively low percentage of subjects with sputum and serology results available. Hospitalized RSV ARI burden estimates in adults based solely on NP swab RT-PCR should be adjusted for underestimation.

Efficacy of a 4-Antigen Staphylococcus aureus Vaccine in Spinal Surgery: The STRIVE Randomized Clinical Trial

BACKGROUND

Staphylococcus aureus is a global pathogen frequently responsible for healthcare-associated infections, including surgical site infections (SSIs). Current infection prevention and control approaches may be limited, with S aureus antibiotic resistance remaining problematic. Thus, a vaccine to prevent or reduce S aureus infection is critically needed. This study evaluated efficacy and safety of an investigational 4-antigen S aureus vaccine (SA4Ag) in adults undergoing elective open posterior spinal fusion procedures with multilevel instrumentation.

METHODS

In this multicenter, site-level, randomized, double-blind trial, subjects 18-85 years old received a single dose of SA4Ag or placebo 10-60 days before surgery. SA4Ag efficacy in preventing postoperative S aureus bloodstream infection and/or deep incisional or organ/space SSI was the primary endpoint. Safety evaluations included local reactions, systemic events, and adverse events (AEs). Immunogenicity and colonization were assessed.

RESULTS

Study enrollment was halted when a prespecified interim efficacy analysis met predefined futility criteria. SA4Ag showed no efficacy (0.0%) in preventing postoperative S aureus infection (14 cases in each group through postoperative Day 90), despite inducing robust functional immune responses to each antigen compared with placebo. Colonization rates across groups were similar through postoperative Day 180. Local reactions and systemic events were mostly mild or moderate in severity, with AEs reported at similar frequencies across groups.

CONCLUSIONS

In patients undergoing elective spinal fusion surgical procedures, SA4Ag was safe, well tolerated, but despite eliciting substantial antibody responses that blocked key S aureus virulence mechanisms, was not efficacious in preventing S aureus infection. ClinicalTrials.gov: NCT02388165.

Incidence of Lyme Borreliosis in Finland: Exploring Observed Trends Over Time Using Public 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 LB cases were identified from the National Infectious Disease Register 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. Results: A total of 33,185 LB cases were reported for the 2015-2020 period, of which 12,590 (38%) were microbiologically confirmed and 20,595 (62%) were clinically diagnosed. The average annual national incidences for total, microbiologically confirmed, and clinically diagnosed LB were, respectively, 99.6, 38.1, and 61.4 per 100,000 population. The total 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 Åland Islands were a hyperendemic region with an average annual incidence of 2473.9/100,000. The highest incidence was among persons aged >60 years, peaking at age 70-74 years. Most cases were reported between May and October, with a peak in July and August. Conclusions: The incidence of LB varied substantially by hospital district, and many regions reached incidences comparable with other high incidence countries, suggesting preventive measures such as vaccines may be an efficient use of resources.

Incidence of Lyme Borreliosis in Germany: Exploring Observed Trends Over Time Using Public Surveillance Data, 2016-2020

Background: Public surveillance of Lyme borreliosis (LB) occurs in 9 out of 16 federal states of Germany and remains a critical facet of disease epidemiology and trends. We describe the incidence, time trends, seasonality, and geographic distribution of LB in Germany using publicly reported surveillance data. Methods: We obtained LB cases and incidence (2016-2020) from the online platform SurvStat@RKI 2.0, maintained by the Robert Koch Institute (RKI). Data included clinically diagnosed and laboratory-confirmed LB reported by nine out of 16 federal states of Germany where LB notification is mandatory. Results: During 2016-2020, the nine federal states reported 63,940 LB cases, of which 60,570 (94.7%) were clinically diagnosed, and 3370 (5.3%) also had laboratory confirmation, with an average of 12,789 cases annually. Incidence rates were mostly stable over time. The average annual LB incidence was 37.2/100,000 person-years and varied by spatial level, ranging from 22.9 to 64.6/100,000 person-years among nine states; from 16.8 to 85.6/100,000 person-years among 19 regions; and from 2.9 to 172.8/100,000 person-years among 158 counties. Incidence was lowest among persons 20-24 years old (16.1/100,000 person-years) and highest among those 65-69 years old (60.9/100,000 person-years). Most cases were reported between June and September, with a peak in July of every year. Conclusion: The risk of LB varied substantially at the smallest geographic unit and by age group. Our results underscore the importance of presenting LB data at the most spatially granular unit and by age to allow implementation of efficient preventive interventions and reduction strategies.

A Retrospective Database Study of Lyme Borreliosis Incidence in Poland from 2015 to 2019: A Public Health Concern

Background: In Poland, Lyme borreliosis (LB) has been subject to mandatory public health surveillance since 1996 and, in accordance with EU regulations, Lyme neuroborreliosis has been reported to the European Centre for Disease Prevention and Control since 2019. In this study, the incidence, temporal trends, and geographic 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 data sent to the National Institute of Public Health-National Institute of Hygiene-National Research Institute (NIPH-NIH-NRI) by district sanitary epidemiological stations using the electronic Epidemiological Records Registration System and data from the National Database on Hospitalization. Incidence rates were calculated using population data from the Central Statistical Office. Results: During 2015-2019, Poland reported 94,715 cases of LB with an overall average incidence of 49.3 cases per 100,000 population. Cases increased from 2015 (11,945) to 2016 (20,857) and then remained stable through 2019. Hospitalization due to LB also rose during these years. LB was more common among women (55.7%). Erythema migrans and Lyme arthritis were the most common manifestations of LB. The highest incidence rates occurred among >50-year-olds, with a peak in 65-69-year-olds. The highest number of cases was recorded in the third and fourth quarters of the year (July-December). Incidence rates in the eastern and northeastern regions of the country were higher than the national average. Conclusions: LB is endemic in all regions of Poland, and many regions reported high incidence rates. Large variations in spatially granular incidence rates highlight the need for targeted prevention strategies.

Incidence of Lyme Borreliosis in the Dutch General Practice Population: A Large-Scale Population-Based Cohort Study Across the Netherlands Between 2015 and 2019

Background: There is a need for updated incidence rates (IRs) of Lyme borreliosis (LB) in Europe, including the Netherlands. We estimated LB IRs stratified by geographic area, year, age, sex, immunocompromised status, and socioeconomic status (SES). Methods: All subjects registered in the PHARMO General Practitioner (GP) Database without prior diagnosis of LB or disseminated LB and having ≥1 year of continuous database enrolment were included. IRs and corresponding confidence intervals (CIs) of GP-recorded LB, erythema migrans (EM), and disseminated LB were estimated during the period 2015‒2019. Results: We identified 14,794 events (suspected, probable, or confirmed) with a diagnostic code for LB that included 8219 with a recorded clinical manifestation: 7985 (97%) with EM and 234 (3%) with disseminated LB. National annual LB IRs were relatively consistent, ranging from 111 (95% CI 106‒115) in 2019 to 131 (95% CI 126‒136) in 2018 per 100,000 person-years. Incidence of LB showed a bimodal age distribution, with peak IRs observed among subjects aged 5‒14 and 60‒69 years in men and women. Higher LB incidence was found in subjects who were residents of the provinces of Drenthe and Overijssel, immunocompromised, or of lower SES. Similar patterns were observed for EM and disseminated LB. Conclusions: Our findings confirm that LB incidence remains substantial throughout the Netherlands with no indication of decline in the past 5 years. Foci in two provinces and among vulnerable populations suggest potential initial target groups for preventive strategies such as vaccination.

The Landscape of Lyme Borreliosis Surveillance in Europe

Purpose: Lyme borreliosis (LB) is the most prevalent tick-borne disease in Europe and the incidence of LB is increasing owing to an expansion in tick habitats. However, LB surveillance is quite heterogeneous across the continent, and for those countries with publicly available data, it is difficult to understand the differences in incidence between countries. The objective of our study was to summarize the publicly available data from surveillance for LB in the form of surveillance reports and/or dashboards and to compare the information available for various countries. Methods: We identified publicly available LB data (online dashboards and surveillance reports) in the European Union, European Economic Area, the United Kingdom, Russia, and Switzerland. Results: Of the 36 countries studied, 28 had LB surveillance in place; 23 had surveillance reports, and 10 had dashboards. The dashboards, in general, had more granular data compared with the surveillance reports, but the reports covered longer time periods. LB annual cases, incidence, age, and sex-stratified LB data; manifestations; and regional data were available for most of the countries. LB case definitions varied significantly among the countries. Conclusion: The study highlights large differences in LB surveillance systems, including representativeness, case definitions, type of data available that might inhibit comparison of data between countries and accurate determination of burden of disease, and risk groups within countries. Standardization of case definitions across countries would be a useful first step enabling comparisons between countries and contribute to recognizing the true burden of LB in Europe.