Value of rapid testing for influenza among Hajj pilgrims

Emerging Options for the Diagnosis of Bacterial Infections and the Characterization of Antimicrobial Resistance

Precise and rapid identification and characterization of pathogens and antimicrobial resistance patterns are critical for the adequate treatment of infections, which represent an increasing problem in intensive care medicine. The current situation remains far from satisfactory in terms of turnaround times and overall efficacy. Application of an ineffective antimicrobial agent or the unnecessary use of broad-spectrum antibiotics worsens the patient prognosis and further accelerates the generation of resistant mutants. Here, we provide an overview that includes an evaluation and comparison of existing tools used to diagnose bacterial infections, together with a consideration of the underlying molecular principles and technologies. Special emphasis is placed on emerging developments that may lead to significant improvements in point of care detection and diagnosis of multi-resistant pathogens, and new directions that may be used to guide antibiotic therapy.

The Hajj 2019 Vaccine Requirements and Possible New Challenges

Each year millions of pilgrims perform the annual Hajj from more than 180 countries around the world. This is one of the largest mass gathering events and may result in the occurrence and spread of infectious diseases. As such, there are mandatory vaccinations for the pilgrims such as meningococcal vaccines. The 2019 annual Hajj will take place during August 8-13, 2019. Thus, we review the recommended and mandated vaccinations for the 2019 Hajj and Umrah. The mandatory vaccines required to secure the visa include the quadrivalent meningococcal vaccine for all pilgrims, while yellow fever, and poliomyelitis vaccines are required for pilgrims coming from countries endemic or with disease activity. The recommended vaccines are influenza, pneumococcal, in addition to full compliance with basic vaccines for all pilgrims against diphtheria, tetanus, pertussis, polio, measles, and mumps. It is imperative to continue surveillance for the spread of antimicrobial resistance and occurrence of all infectious diseases causing outbreaks across the globe in the last year, like Zika virus, MDR-Typhoid, Nipah, Ebola, cholera, chikungunya and Middle East Respiratory Syndrome Coronavirus.

A systematic review of emerging respiratory viruses at the Hajj and possible coinfection with Streptococcus pneumoniae

Background

The annual Hajj to the Kingdom of Saudi Arabia attracts millions of pilgrims from around the world. International health community's attention goes towards this mass gathering and the possibility of the development of any respiratory tract infections due to the high risk of acquisition of respiratory viruses.

Method

We searched MEDLINE/PubMed and Scopus databases for relevant papers describing the prevalence of respiratory viruses among Hajj pilgrims.

Results

The retrieved articles were summarized based on the methodology of testing for these viruses. A total of 31 studies were included in the quantitative/qualitative analyses. The main methods used for the diagnosis of most common respiratory viruses were polymerase chain reaction (PCR), culture and enzyme-linked immunosorbent assay (ELISA). Influenza, rhinovirus and parainfluenza were the most common viruses detected among pilgrims. Coronaviruses other than MERS-CoV were also detected among pilgrims. The acquisition of MERS-CoV remains very limited and systematic screening of pilgrims showed no infections.

Conclusions

Well conducted multinational follow-up studies using the same methodology of testing are necessary for accurate surveillance of respiratory viral infections among Hajj pilgrims. Post-Hajj cohort studies would further evaluate the impact of the Hajj on the acquisition of respiratory viruses.

Expected immunizations and health protection for Hajj and Umrah 2018 -An overview

BACKGROUND

The annual Hajj and Umrah are one of the largest recurring religious mass gatherings across the globe drawing pilgrims from more than 185 countries. The living circumstances and activities of the pilgrims may create an environment for the occurrence and spread of communicable diseases. Each year, the Health authority of the Kingdom of Saudi Arabia, in coordination with international health authorities, updates health requirements for pilgrims. The Hajj for 2017 took place from August 24 to September 5, 2017. Here, we review the expected obligations for immunizations for the 2018 Hajj and Umrah.

RESULTS

The Hajj and Umrah vaccine requirements include mandatory vaccinations against yellow fever, quadrivalent meningococcal polysaccharide (every 3 years) or conjugated (every 5 years) vaccines and poliomyelitis vaccine. Influenza vaccine utilizing the 2016 (Southern Hemisphere vaccine to all pilgrims) was recommended but was not obligatory for pilgrims. Ciprofloxacin is required for individuals >12 years excluding pregnant women as chemoprophylaxis to be given at the port of entry for Pilgrims coming from the meningitis belt. With the ongoing outbreaks of measles in Europe, it is recommended that all pilgrims have an updated immunization against vaccine-preventable diseases (diphtheria, tetanus, pertussis, polio, measles and mumps).

CONCLUSION

The mandatory vaccines remain the same with continued vigilance for the development of any new or emerging infectious diseases. Continuing surveillance for Zika virus, cholera and MERS-CoV are ongoing.

The Point-of-Care Laboratory in Clinical Microbiology

Point-of-care (POC) laboratories that deliver rapid diagnoses of infectious diseases were invented to balance the centralization of core laboratories. POC laboratories operate 24 h a day and 7 days a week to provide diagnoses within 2 h, largely based on immunochromatography and real-time PCR tests. In our experience, these tests are conveniently combined into syndrome-based kits that facilitate sampling, including self-sampling and test operations, as POC laboratories can be operated by trained operators who are not necessarily biologists. POC laboratories are a way of easily providing clinical microbiology testing for populations distant from laboratories in developing and developed countries and on ships. Modern Internet connections enable support from core laboratories. The cost-effectiveness of POC laboratories has been established for the rapid diagnosis of tuberculosis and sexually transmitted infections in both developed and developing countries.

Hajj-associated viral respiratory infections: A systematic review

Respiratory tract infections (RTI) are the most common infections transmitted between Hajj pilgrims. The aim of this systematic review was to determine the prevalence of virus carriage potentially responsible for RTI among pilgrims before and after participating in the Hajj. A systematic search for relevant literature was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. 31 studies were identified. Severe Acute Respiratory Syndrome coronavirus and Middle East Respiratory Syndrome coronavirus (MERS) were never isolated in Hajj pilgrims. The viruses most commonly isolated from symptomatic patients during the Hajj by PCR were rhinovirus (5.9-48.8% prevalence), followed by influenza virus (4.5-13.9%) and non-MERS coronaviruses (2.7-13.2%) with most infections due to coronavirus 229E; other viruses were less frequently isolated. Several viruses including influenza A, rhinovirus, and non-MERS coronaviruses had low carriage rates among arriving pilgrims and a statistically significant increase in their carriage rate was observed, following participation in the Hajj. Further research is needed to assess the role of viruses in the pathogenesis of respiratory symptoms and their potential role in the severity of the symptoms.

Performance of rapid influenza diagnostic tests (QuickVue) for influenza A and B Infection in India

BACKGROUND

Rapid point-of-care (POC) tests provide an economical alternative for rapid diagnosis and treatment of influenza, especially in public health emergency situations.

OBJECTIVES

To test the performance of a rapid influenza diagnostic test, QuickVue (Quidel) as a POC test against a real-time polymerase chain reaction (RT-PCR) assay for detection of influenza A and B in a developing country setting.

STUDY DESIGN

In a prospective observational design, 600 patients with influenza-like illness (ILI) or with severe acute respiratory illness (SARI) who were referred to the Influenza Clinic of a tertiary care hospital in Srinagar, India from September 2012 to April 2013, were enrolled for diagnostic testing for influenza using QuickVue or RT-PCR. All influenza A-positive patients by RT-PCR were further subtyped using primers and probes for A/H1pdm09 and A/H3.

RESULTS

Of the 600 patients, 186 tested positive for influenza A or B by RT-PCR (90 A/H1N1pdm09, 7 A/H3 and 89 influenza B), whereas only 43 tested positive for influenza (influenza A=22 and influenza B=21) by QuickVue. Thus, the sensitivity of the QuickVue was only 23% (95% confidence interval, CI: 17.3-29.8) and specificity was 100% (95% CI: 99.1-100) with a positive predictive value (PPV) of 100% (95% CI 91.8-100) and a negative predictive value (NPV) of 74.3% (95% CI: 70.5-77.9) as compared to RT-PCR.

CONCLUSIONS

The high specificity of QuickVue suggest that this POC test can be a useful tool for patient management or triaging during a public health crisis but a low sensitivity suggests that a negative test result need to be further tested using RT-PCR.

Clinical diagnosis of pandemic A(H1N1) 2009 influenza in children with negative rapid influenza diagnostic test by lymphopenia and lower C-reactive protein levels

Background

The sensitivity of rapid influenza diagnostic test (RIDT) of children with influenza-like illness (ILI) remains low.

Objective

We compare the parameters between pandemic A(H1N1) 2009 influenza with negative RIDT and ILI not H1N1 for improving the low sensitivity of RIDT for children with ILI.

Methods

In a cohort of consecutive laboratory-confirmed H1N1 influenza, we identified 150 H1N1 children with positive RIDT, 152 H1N1 children with negative RIDT, and 75 children with ILI not H1N1. Viral load in throat, complete blood count (CBC), and C-reactive protein (CRP) levels between H1N1 children with negative RIDT and children with ILI not H1N1 were assessed.

Results

The diagnostic sensitivity of the RIDT was 45·5%. An analysis of CBC and CRP levels indicated that H1N1 children with negative RIDT had lower total leukocyte, neutrophil, lymphocyte, and basophil counts, and serum CRP levels (P < 0·01). Lymphocyte counts less than 1500 cells/mm³ and CRP levels <15 mg/l, determined by a receiver operating characteristic curve, showed a diagnostic sensitivity of 52·5% and 80·7%, respectively. Combining the lymphocyte counts and CRP levels provided a diagnostic sensitivity of 91·5%. Moreover, H1N1 children with negative RIDT had a lower viral load than those with positive RIDT (3·33 versus 4·48 log₁₀ copies/ml, P < 0·001); the viral load was negatively correlated to the lymphocyte count (P < 0·001).

Conclusions

A combination of a low lymphocyte count and a low CRP level could, in the early disease phase, provide a useful screening for H1N1 children with false-negative RIDT, potentially facilitating differential diagnoses.

Prevention of influenza at Hajj: applications for mass gatherings

Outbreaks of infectious diseases that spread via respiratory route, e.g. influenza, are common amongst Hajj congregation in Mecca, Saudi Arabia. The Saudi Arabian authority successfully organized the Hajj 2009 amidst fear of pandemic influenza. While severe influenza A(H1N1)pdm09 was rare, the true burden of pandemic influenza at Hajj that year remains speculative. In this article we review the latest evidence on influenza control and discuss our experience of influenza and its prevention at Hajj and possible application to other mass gatherings. Depending on study design the attack rate of seasonal influenza at Hajj has ranged from 6% in polymerase chain reaction or culture confirmed studies to 38% in serological surveillance. No significant effect of influenza vaccine or the use of personal protective measures against influenza has been established from observational studies, although the uptake of the vaccine and adherence to face masks and hand hygiene has been low. In all, there is a relatively poor evidence base for control of influenza. Until better evidence is obtained, vaccination coupled with rapid antiviral treatment of symptomatic individuals remains the mainstay of prevention at Hajj and other mass gatherings. Hajj pilgrimage provides a unique opportunity to test the effectiveness of various preventive measures that require a large sample size, such as testing the efficacy of plain surgical masks against laboratory-confirmed influenza. After successful completion of a pilot trial conducted among Australian pilgrims at the 2011 Hajj, a large multinational cluster randomized controlled trial is being planned. This will require effective international collaboration.

Point-of-care tests for infection control: should rapid testing be in the laboratory or at the front line?

BACKGROUND

A point-of-care test (POCT) offers a rapid result to manage a patient immediately. The presumed simplicity of such tests belies observed variation between personnel in performing and interpreting results when not appropriately trained. The number of point-of-care devices being developed for the diagnosis of infectious diseases is increasing; by understanding the limitations associated with their use, such tests for infection control purposes may be possible.

AIM

To review the expanding repertoire of POCTs for the diagnosis of infectious diseases and to assess their utility as tools to aid in the reduction of hospital-acquired infection and outbreak management.

METHODS

A systematic review using PubMed and Scopus of published literature on the subject of POCTs for the diagnosis of infectious diseases.

FINDINGS

Although the number of publications describing POCTs is increasing, there remains a paucity of literature describing their use in a clinical setting. Of the literature reviewed, POCTs for the diagnosis of respiratory syncytial virus and norovirus have the greatest utility in an infection control setting, although the data suggest that sensitivity and training issues might be a problem. The future generation of POCT devices is likely to be molecular-based, improving sensitivity but at a significant cost to the user.

CONCLUSIONS

POCTs have a role in infection control but currently the lack of good, consistent clinical data surrounding their use outside of the laboratory is a limiting factor in their implementation.

Diagnosis of 2009 pandemic influenza A (pH1N1) and seasonal influenza using rapid influenza antigen tests, San Antonio, Texas, April-June 2009

Clinicians frequently use influenza rapid antigen tests for diagnostic testing. We tested nasal wash samples from 1 April to 7 June 2009 from 1538 patients using the QuickVue Influenza A+B (Quidel) rapid influenza antigen test and compared the results with real-time reverse transcription polymerase chain reaction (rRT-PCR) assay (gold standard). The prevalence of 2009 pandemic influenza A (pH1N1) was 1.98%, seasonal influenza type A .87%, and seasonal influenza type B 2.07%. The sensitivity and specificity of the rapid test for pH1N1 was 20% (95% CI, 8-39) and 99% (95% CI, 98-99), for seasonal influenza type A 15% (95% CI, 2-45) and 99% (95% CI, 98-99), and for influenza type B was 31% (95% CI, 9-61) and 99% (95% CI, 98-99.7). Rapid influenza antigen tests were of limited use at a time when the prevalence of pH1N1 and seasonal influenza in the United States was low. Clinicians should instead rely on clinical impression and laboratory diagnosis by rRT-PCR.

Sensitivity and specificity of rapid influenza testing of children in a community setting

Please cite this paper as: Stebbins et al. (2011) Sensitivity and specificity of rapid influenza testing of children in a community setting. Influenza and Other Respiratory Viruses 5(2), 104–109.

Introduction  Rapid influenza testing (RFT) allows for a rapid point‐of‐care diagnosis of influenza. The Quidel QuickVue^® Influenza A+B test (QuickVue) has a reported manufacturer’s sensitivity and specificity of 73% and 96%, respectively, with nasal swabs. However, investigators have shown sensitivities ranging from 22% to 77% in community settings.

Methods  The QuickVue rapid influenza test was evaluated in a population of elementary (K‐5) school children, using testing in the home, as part of the Pittsburgh Influenza Prevention Project during the 2007–2008 influenza season. The QuickVue test was performed with nasal swab in full accordance with package instructions and compared with the results of nasal swab semi‐quantitative RT‐PCR.

Results  Sensitivity of the QuickVue was found to be 27% in this sample. There was no statistically valid correlation between the semi‐quantitative PCR result and the QuickVue result.

Conclusions  This study is consistent with the low sensitivity of the QuickVue test also reported by others. Viral load, technique, and the use of nasal swabs were examined as contributing factors but were not found to be explanations for this result. Community testing includes patients who are on the lower spectrum of illness which would not be the case in hospital or clinic samples. This suggests that RFT is less sensitive for patients at the lower spectrum of illness, with less severe disease.

Failure of routine diagnostic methods to detect influenza in hospitalized older adults

OBJECTIVE

To define the utility of using routine diagnostic methods to detect influenza in older, hospitalized adults.

DESIGN

Descriptive study.

SETTING

One academic hospital and 1 community hospital during the 2006-2007 and 2007-2008 influenza seasons. Participants. Hospitalized adults 50 years of age or older.

METHODS

Adults who were 50 years of age or older and hospitalized with symptoms of respiratory illness were enrolled and tested for influenza by use of reverse-transcriptase polymerase chain reaction (RT-PCR). Using RT-PCR as the gold standard, we assessed the performances of rapid antigen tests and conventional influenza culture and the diagnostic use of the clinical definition of influenza-like illness.

RESULTS

Influenza was detected by use of RT-PCR in 26 (11%) of 228 patients enrolled in our study. The sensitivity of the rapid antigen test performed at bedside by research staff members was 19.2% (95% confidence interval, 8.51%-37.9%); the sensitivity of conventional influenza culture was 34.6% (95% confidence interval, 19.4%-53.8%). The ability to detect influenza with both the rapid antigen test and culture was associated with patients with a higher viral load (P=.002 and P=.001, respectively). The ability to diagnose influenza by use of the clinical definition of influenza-like illness had a higher sensitivity (80.8%) but lacked specificity (40.6%).

CONCLUSION

Because rapid antigen testing and viral culture have poor sensitivity (19.2% and 34.6%, respectively), neither testing method is sufficient to use to determine what type of isolation procedures to implement in a hospital setting.

Evaluation of QuickVue influenza A+B rapid test for detection of pandemic influenza A/H1N1 2009

BACKGROUND

A novel influenza A/H1N1 emerged in early 2009 and by June 2009 was declared a pandemic by WHO. Rapid influenza antigen detection tests have been used to diagnose seasonal influenza but have not been adequately evaluated for the pandemic strain among all age groups. In the Philippines, pandemic influenza A/H1N1 2009 was first detected in May 2009 and by July 2009, 3207 cases and 6 deaths were reported.

OBJECTIVES

Using RT-PCR as the gold standard, clinical sensitivity/specificity of Quidel QuickVue (QV) influenza A+B was estimated across all age groups for pandemic influenza A/H1N1 using nasal swabs in a hospital setting. Effect of age, viral titers (Ct values), and timing of collection on QV sensitivity to detect pandemic influenza A/H1N1 2009 was also determined.

STUDY DESIGN

Febrile patients with influenza-like illness (n=360) at the V. Luna General Hospital, Manila from 1 June to 31 August 2009 were included. Nasal swabs were tested using QV and RT-PCR.

RESULTS

Of 360 nasal specimens 226 (63%) were positive for pandemic influenza A/H1N1. QV sensitivity was 63% (95% confidence interval (CI): 56-69%), specificity was 96% (95% CI: 91-99%), positive predictive value was 97% (CI: 93-99%), and negative predictive value was 57% (95% CI: 49-64%). Patient's age, fever severity, presenting symptoms or number of symptoms did not significantly affect QV sensitivity, however QV sensitivity was correlated with decreasing Ct values.

CONCLUSION

QuickVue demonstrated moderate sensitivity for pandemic influenza A/H1N1 infection. There was a significant inverse association between Ct values and QV sensitivity for pandemic influenza A/H1N1.

Rapid diagnostic testing for seasonal influenza: an evidence-based review and comparison with unaided clinical diagnosis

BACKGROUND

Worldwide, seasonal influenza imposes a considerable health and economic burden. Clinical diagnosis of influenza-like illness (ILI) is complicated by non-specific symptomatology. Rapid flu tests (RFTs) impact treatment decisions and may improve patient care; yet, recommendations for RFT use are broad, and the performance of unaided clinical diagnosis relative to RFTs is unclear.

OBJECTIVES

To determine age-stratified, overall sensitivities and specificities of the widely studied RFT, QuickVue® (Quidel Corporation, San Diego, CA), and clinical diagnosis of ILI by meta-analysis and to seek factors associated with poorer clinical diagnostic discrimination.

METHODS

A systematic literature review was conducted using article selection criteria identifying studies indexed in PubMed/MEDLINE, the Cochrane Library, and other pertinent sources of studies reporting sensitivity, specificity, and effects of RFTs and clinical diagnosis on decision-making for patients with ILI.

RESULTS

QuickVue's® diagnostic specificity exceeds that of unaided clinical diagnosis by 29-31%. False-positive results occur approximately 8.2 times more frequently by unaided clinical diagnosis than by the RFT alone. These findings were unaffected by seasonal variations in disease prevalence. RFTs reduce diagnostic testing, antibiotic use, and emergency department utilization while increasing antiviral prescription rates. No systematic relationship between the broadness of clinical diagnostic criteria for influenza and diagnostic performance was observed across studies included in this review.

CONCLUSIONS

Use of RFTs improves seasonal influenza diagnostic specificity above that based on unaided clinical diagnosis irrespective of the broadness of clinical diagnostic criteria, and affects clinical decision-making. These results provide an improved framework upon which to diagnose influenza, design future RFT studies, and modify existing recommendations for improved ILI patient management.

The prevalence of acute respiratory symptoms and role of protective measures among Malaysian hajj pilgrims

BACKGROUND

Respiratory symptoms including cough, runny nose, sore throat, and fever are the most common clinical manifestations faced by hajj pilgrims in Mecca. The aim of the study was to determine the prevalence of respiratory symptoms among Malaysian hajj pilgrims and the effect of a few protective measures taken by hajj pilgrims to reduce respiratory symptoms.

METHODS

A cross-sectional study was conducted by distributing survey forms to Malaysian hajj pilgrims at transit center before flying back to Malaysia. The recruitment of respondents to the survey was on a voluntary basis.

RESULTS

A total of 387 survey forms were available for analysis. The mean age was 50.4 +/- 11.0 years. The common respiratory symptoms among Malaysian hajj pilgrims were: cough 91.5%, runny nose 79.3%, fever 59.2%, and sore throat 57.1%. The prevalence of hajj pilgrims with triad of cough, subjective fever, and sore throat were 40.1%. The symptoms lasted less than 2 weeks in the majority of cases. Only 3.6% did not suffer from any of these symptoms. Seventy-two percent of hajj pilgrims received influenza vaccination before departure and 72.9% wore facemasks. Influenza vaccination was not associated with any of respiratory symptoms but it was significantly associated with longer duration of sore throat. Wearing masks was significantly associated with sore throat and longer duration of sore throat and fever.

CONCLUSIONS

The prevalence of respiratory symptoms was high among Malaysian hajj pilgrims and the current protective measures seemed inadequate to reduce it. Beside standardization of the term used in hajj studies, more collaborative effort should be taken to reduce respiratory symptoms. The hajj authority should prepare for the challenge of pandemic influenza by providing more healthcare facilities and implementation of more strict measures to reduce the transmission of pandemic influenza strain among hajj pilgrims.

Establishment of public health security in Saudi Arabia for the 2009 Hajj in response to pandemic influenza A H1N1

Mass gatherings of people challenge public health capacities at host locations and the visitors' places of origin. Hajj--the yearly pilgrimage by Muslims to Saudi Arabia--is one of the largest, most culturally and geographically diverse mass gatherings in the world. With the 2009 pandemic influenza A H1N1 and upcoming Hajj, the Saudi Arabian Ministry of Health (MoH) convened a preparedness consultation in June, 2009. Consultants from global public health agencies met in their official capacities with their Saudi Arabian counterparts. The MoH aimed to pool and share public health knowledge about mass gatherings, and review the country's preparedness plans, focusing on the prevention and control of pandemic influenza. This process resulted in several practical recommendations, many to be put into practice before the start of Hajj and the rest during Hajj. These preparedness plans should ensure the optimum provision of health services for pilgrims to Saudi Arabia, and minimum disease transmission on their return home. Review of the implementation of these recommendations and their effect will not only inform future mass gatherings in Saudi Arabia, but will also strengthen preparedness efforts in other settings.

The limitations of point of care testing for pandemic influenza: what clinicians and public health professionals need to know

As the world prepares for the next influenza pandemic, governments have made significant funding commitments to vaccine development and antiviral stockpiling. While these are essential components to pandemic response, rapid and accurate diagnostic testing remains an often neglected cornerstone of pandemic influenza preparedness. Clinicians and Public Health Practitioners need to understand the benefits and drawbacks of different influenza tests in both seasonal and pandemic settings. Culture has been the traditional gold standard for influenza diagnosis but requires from 1-10 days to generate a positive result, compared to nucleic acid detection methods such as real time reverse transcriptase polymerase chain reaction (RT-PCR). Although the currently available rapid antigen detection kits can generate results in less than 30 minutes, their sensitivity is suboptimal and they are not recommended for the detection of novel influenza viruses. Until point-of-care (POC) tests are improved, PILPN recommends that the best option for pandemic influenza preparation is the enhancement of nucleic acid-based testing capabilities across Canada.

Field performance of a rapid diagnostic test for influenza in an ambulatory setting

Provided test characteristics are adequate, point-of-care rapid antigen detection tests for influenza could improve the timeliness and appropriateness of clinical decisions. Our objective was to estimate the field sensitivity and specificity of the Quidel QuickVue Influenza A+B test in an ambulatory setting. The sensitivity and specificity of the Quidel QuickVue test was evaluated against reverse-transcriptase PCR (RT-PCR) on nasopharyngeal specimens collected over two consecutive influenza seasons from ambulatory patients consulting for influenza-like illness (ILI) within 7 days of ILI onset. A total of 491 patients with ILI (180 in 2006 to 2007 and 311 in 2007 to 2008) provided specimens that were tested both by PCR and by the Quidel QuickVue test. Among the 267 patients positive by PCR (55%), 52 were also positive by the QuickVue test, for an overall sensitivity of 19.5% (95% confidence interval [95% CI], 14.7% to 24.2%). Among the 221 PCR-negative patients, 2 were positive for influenza B virus by the rapid test (<1%), for an overall specificity of 99.1% (95% CI, 97.9 to 100%). The field sensitivity of the test varied little with the age or gender of the patient, immunization status, delay since the onset of symptoms, or influenza season. The sensitivity of the test was slightly but nonsignificantly higher for influenza B virus (23%) than for influenza A virus (18%). Despite its high specificity, the low sensitivity of the Quidel QuickVue Influenza A+B test is too poor to direct clinical decisions for ambulatory patients with ILI. Negative results cannot rule out the diagnosis of influenza, and in that context, this test is of questionable utility for routine application in the clinical setting.

Seasonal influenza in adults and children--diagnosis, treatment, chemoprophylaxis, and institutional outbreak management: clinical practice guidelines of the Infectious Diseases Society of America

Guidelines for the treatment of persons with influenza virus infection were prepared by an Expert Panel of the Infectious Diseases Society of America. The evidence-based guidelines encompass diagnostic issues, treatment and chemoprophylaxis with antiviral medications, and issues related to institutional outbreak management for seasonal (interpandemic) influenza. They are intended for use by physicians in all medical specialties with direct patient care, because influenza virus infection is common in communities during influenza season and may be encountered by practitioners caring for a wide variety of patients.

Early diagnosis of lower respiratory tract infections (point-of-care tests)

PURPOSE OF REVIEW

Respiratory tract infections are a common reason for prescribing antibiotics, although not all of these infections require such therapy. Rapid diagnosis of etiology using point-of-care tests is a potentially useful way of reducing prescriptions of both unnecessary and unnecessarily broad-spectrum antibiotics. This can also lead to the facilitation of appropriate infection control measures to prevent spread of respiratory viruses within institutions.

RECENT FINDINGS

Point-of-care tests are available for diagnosing influenza, respiratory syncytial virus, Streptococcus pneumoniae, and Legionella infections using easily obtainable specimens. Their main benefit is that results can be obtained in about 15 min with reasonable accuracy. In many situations, however, it is still important to confirm diagnosis with more accurate but slower tests such as bacterial cultures with antibacterial susceptibility testing or viral polymerase chain reaction testing.

SUMMARY

Although the sensitivities of many of the rapid diagnostic tests are moderate, when used at the time of initial consultation, they have the potential to reduce costs, length of stay, secondary spread of respiratory viruses, and inappropriate antibiotic prescribing.