Delayed/back up antibiotic prescriptions: what do the public think?

Delayed and Non-Antibiotic Therapy for Urinary Tract Infections: A Literature Review

Urinary tract infections are among the most common infections encountered in the clinic and remain a top indication for women to receive antibiotics. Delayed antibiotic prescribing and non-antibiotic symptomatic therapies are treatment paradigms common to other uncomplicated infectious diseases, such as upper respiratory infections. We aimed to review the literature on delayed antibiotics and non-antibiotic treatments as alternatives to immediate antibiotic prescriptions for uncomplicated cystitis. A literature search was performed in PubMed, Google Scholar, and Web of Science to identify relevant clinical trials and reference lists of included articles were examined to find additional studies. All published trials where same day treatment with antibiotics was compared to scenarios where antibiotics were intentionally delayed or withheld or where antibiotics were compared to non-antimicrobial agents or placebo were analyzed. A total of 13 articles were included. Trials were grouped into categories based on their comparator groups: placebo (n = 5), delayed antibiotic therapy (n = 3), and symptomatic treatment (n = 5). Antibiotic delay and ibuprofen, while less effective than antibiotics in early microbiologic and clinical cure, may still be considered plausible alternatives to immediate antibiotic treatment in non-pregnant women with cystitis. Day 7 and later symptomatic resolution ranges from 26-75% with delayed or placebo therapy and 70-83% with nonsteroidal anti-inflammatory drugs. Symptom improvement, however, may be delayed compared to immediate antibiotics. These approaches have shown to decrease antibiotic use in primary care settings with low rates of pyelonephritis. Methodology included in these studies may be considered in stewardship interventions for outpatient clinics.

Implementing antibiotic stewardship in high-prescribing English general practices: a mixed-methods study

BACKGROUND

Trials have identified antimicrobial stewardship (AMS) strategies that effectively reduce antibiotic use in primary care. However, many are not commonly used in England. The authors co-developed an implementation intervention to improve use of three AMS strategies: enhanced communication strategies, delayed prescriptions, and point-of-care C-reactive protein tests (POC-CRPTs).

AIM

To investigate the use of the intervention in high-prescribing practices and its effect on antibiotic prescribing.

DESIGN AND SETTING

Nine high-prescribing practices had access to the intervention for 12 months from November 2019. This was primarily delivered remotely via a website with practices required to identify an 'antibiotic champion'.

METHOD

Routinely collected prescribing data were compared between the intervention and the control practices. Intervention use was assessed through monitoring. Surveys and interviews were conducted with professionals to capture experiences of using the intervention.

RESULTS

There was no evidence that the intervention affected prescribing. Engagement with intervention materials differed substantially between practices and depended on individual champions' preconceptions of strategies and the opportunity to conduct implementation tasks. Champions in five practices initiated changes to encourage use of at least one AMS strategy, mostly POC-CRPTs; one practice chose all three. POC-CRPTs was used more when allocated to one person.

CONCLUSION

Clinicians need detailed information on exactly how to adopt AMS strategies. Remote, one-sided provision of AMS strategies is unlikely to change prescribing; initial clinician engagement and understanding needs to be monitored to avoid misunderstanding and suboptimal use.

What the public in England know about antibiotic use and resistance in 2020: a face-to-face questionnaire survey

OBJECTIVES

To describe public attitudes and knowledge around antibiotic activity, resistance and use.

DESIGN

Face-to-face household 18 question survey using computer-assisted data collection undertaken by Ipsos Market and Opinion Research International.

SETTING

Randomly selected households across England, January-February 2020.

PARTICIPANTS

2022 adults (aged 15+,) including 521 black, Asian and minority ethnic (BAME) participants, and 406 aged 15-25 years olds.

MAIN OUTCOME MEASURES

Responses to questions about antibiotic activity, resistance and expectations for antibiotics and trust in healthcare professionals. Analyses were weighted to obtain estimates representative of the population with multivariable analysis undertaken for questions with five or more significant univariate variables.

RESULTS

84% stated they would be pleased if their general practitioner (GP) said they did not need antibiotics. Trust in GPs to make antibiotic decisions remains high (89%) and has increased for nurses (76%) and pharmacists (71%). Only 21% would challenge an antibiotic decision; this was significantly greater in BAME participants (OR 2.5; 95% CI 1.89 to 3.35). 70% reported receiving advice when prescribed antibiotics. Belief in benefits of antibiotics for ear infections was very high (68%). Similar to 2017, 81% agreed that antibiotics work for bacterial, 28% cold and influenza viruses. 84% agreed antibiotic resistant bacteria (ARB) are increasing, only 50% agreed healthy people can carry ARB and 39% agreed there was nothing they personally could do about ARB. Social grade DE and BAME participants, and those with less education had significantly less understanding about antibiotics and resistance.

CONCLUSIONS

As trust in healthcare practitioners is high, we need to continue antibiotic education and other interventions at GP surgeries and community pharmacies but highlight that most ear infections are not benefitted by antibiotics. Targeted interventions are needed for socioeconomic DE, BAME groups and previous antibiotic users. We need to explore if increasing perceived personal responsibility for preventing ARB reduces antibiotic use.

Public preferences for delayed or immediate antibiotic prescriptions in UK primary care: A choice experiment

BACKGROUND

Delayed (or "backup") antibiotic prescription, where the patient is given a prescription but advised to delay initiating antibiotics, has been shown to be effective in reducing antibiotic use in primary care. However, this strategy is not widely used in the United Kingdom. This study aimed to identify factors influencing preferences among the UK public for delayed prescription, and understand their relative importance, to help increase appropriate use of this prescribing option.

METHODS AND FINDINGS

We conducted an online choice experiment in 2 UK general population samples: adults and parents of children under 18 years. Respondents were presented with 12 scenarios in which they, or their child, might need antibiotics for a respiratory tract infection (RTI) and asked to choose either an immediate or a delayed prescription. Scenarios were described by 7 attributes. Data were collected between November 2018 and February 2019. Respondent preferences were modelled using mixed-effects logistic regression. The survey was completed by 802 adults and 801 parents (75% of those who opened the survey). The samples reflected the UK population in age, sex, ethnicity, and country of residence. The most important determinant of respondent choice was symptom severity, especially for cough-related symptoms. In the adult sample, the probability of choosing delayed prescription was 0.53 (95% confidence interval (CI) 0.50 to 0.56, p < 0.001) for a chesty cough and runny nose compared to 0.30 (0.28 to 0.33, p < 0.001) for a chesty cough with fever, 0.47 (0.44 to 0.50, p < 0.001) for sore throat with swollen glands, and 0.37 (0.34 to 0.39, p < 0.001) for sore throat, swollen glands, and fever. Respondents were less likely to choose delayed prescription with increasing duration of illness (odds ratio (OR) 0.94 (0.92 to 0.96, p < 0.001)). Probabilities of choosing delayed prescription were similar for parents considering treatment for a child (44% of choices versus 42% for adults, p = 0.04). However, parents differed from the adult sample in showing a more marked reduction in choice of the delayed prescription with increasing duration of illness (OR 0.83 (0.80 to 0.87) versus 0.94 (0.92 to 0.96) for adults, p for heterogeneity p < 0.001) and a smaller effect of disruption of usual activities (OR 0.96 (0.95 to 0.97) versus 0.93 (0.92 to 0.94) for adults, p for heterogeneity p < 0.001). Females were more likely to choose a delayed prescription than males for minor symptoms, particularly minor cough (probability 0.62 (0.58 to 0.66, p < 0.001) for females and 0.45 (0.41 to 0.48, p < 0.001) for males). Older people, those with a good understanding of antibiotics, and those who had not used antibiotics recently showed similar patterns of preferences. Study limitations include its hypothetical nature, which may not reflect real-life behaviour; the absence of a "no prescription" option; and the possibility that study respondents may not represent the views of population groups who are typically underrepresented in online surveys.

CONCLUSIONS

This study found that delayed prescription appears to be an acceptable approach to reducing antibiotic consumption. Certain groups appear to be more amenable to delayed prescription, suggesting particular opportunities for increased use of this strategy. Prescribing choices for sore throat may need additional explanation to ensure patient acceptance, and parents in particular may benefit from reassurance about the usual duration of these illnesses.

Alternative approaches to managing respiratory tract infections: a survey of public perceptions

BACKGROUND

Respiratory tract infections (RTIs) are a common reason for people to consult in primary care, and contribute to antibiotic overuse and antimicrobial resistance (AMR). Alternative approaches to supporting patients with RTIs may help, but it is important to understand public perceptions about these approaches before they are widely implemented.

AIM

To describe public perceptions regarding finger-prick testing, back-up antibiotic prescriptions (BUPs), and alternatives to traditional consultations for RTIs, and identify factors associated with favouring these approaches.

DESIGN & SETTING

Online national survey (HealthWise Wales) with linked primary care health record data.

METHOD

Survey item response distributions were described. Associations between responses about consultation alternatives, BUP, and finger-prick point-of-care testing (POCT), and potential explanatory variables, were explored using logistic regression.

RESULTS

A total of 8752 participants completed the survey between 2016 and 2018. The survey found 76.7% (n = 3807/4,966) and 71.2% (n = 3529/4,953) of responders with valid responses were in favour of being able to consult with a pharmacist or nurse in their GP surgery, or with a community pharmacist, respectively. It also showed 92.8% (n = 8034/8659) of responders indicated they would be happy to have a finger-prick test to guide antibiotic prescribing, and 31.8% (n = 2746/8646) indicated they would like to be given a BUP if their clinician thought immediate antibiotics were not required. In addition, 47.4% (n = 2342/4944) and 42.3% (n = 2095/4949) were in favour of having video and email consultations, respectively. Characteristics associated with different response options were identified.

CONCLUSION

Consulting with pharmacists, using electronic communication tools, and finger-prick testing are widely acceptable approaches. BUP was described as acceptable less often, and is likely to require greater information and support when used.

Adherence and the Moral Construction of the Self: A Narrative Analysis of Anticoagulant Medication

In this article, we examine illness narratives to illuminate the discursive work that patients undertake to construct themselves as "good" and adherent. Biographical narrative interviews were undertaken with 17 patients receiving anticoagulation for stroke prevention in atrial fibrillation, from five English hospitals (May 2016-June 2017). Through pluralistic narrative analysis, we highlight the discursive tensions narrators face when sharing accounts of their medicine-taking. They undertake challenging linguistic and performative work to reconcile apparently paradoxical positions. We show how the adherent patient is co-constructed through dialogue at the intersection of discourses including authority of doctors, personal responsibility for health, scarcity of resources, and deservingness. We conclude that the notion of medication adherence places a hidden moral and discursive burden of treatment on patients which they must negotiate when invited into conversations about their medications. This discursive work reveals, constitutes, and upholds medicine-taking as a profoundly moral practice.

Implementation of a Delayed Prescribing Model to Reduce Antibiotic Prescribing for Suspected Upper Respiratory Tract Infections in a Hospital Outpatient Department, Ghana

Background: High levels of antimicrobial resistance (AMR) in Ghana require the exploration of new approaches to optimise antimicrobial prescribing. This study aims to establish the feasibility of implementation of different delayed/back-up prescribing models on antimicrobial prescribing for upper respiratory tract infections (URTIs). Methods: This study was part of a quality improvement project at LEKMA Hospital, Ghana, (Dec 2019-Feb 2020). Patients meeting inclusion criteria were assigned to one of four groups (Group 0: No prescription given; Group 1; Patient received post-dated antibiotic prescription; Group 2: Offer of a rapid reassessment of patient by a nurse practitioner after 3 days; and Group 3: Post-dated prescription forwarded to hospital pharmacy). Patients were contacted 10 days afterwards to ascertain wellbeing and actions taken, and patients were asked rate the service on a Likert scale. Post-study informal discussions were conducted with hospital staff. Results: In total, 142 patients met inclusion criteria. Groups 0, 1, 2 and 3 had 61, 16, 44 and 21 patients, respectively. Common diagnosis was sore throat (73%). Only one patient took antibiotics after 3 days. Nearly all (141/142) patients were successfully contacted on day 10, and of these, 102 (72%) rated their experiences as good or very good. Informal discussions with staff revealed improved knowledge of AMR. Conclusions: Delayed/back-up prescribing can reduce antibiotic consumption amongst outpatient department patients with suspected URTIs. Delayed/back-up prescribing can be implemented safely in low and middle-income countries (LMICs).

[Prescribing of antibiotics for respiratory tract infections in German outpatient pediatric care : Results of a survey of pediatricians and general practitioners]

BACKGROUND

Pediatric outpatients with respiratory tract infections (RTIs) comprise an important target population for antibiotic stewardship (ABS) intervention.

OBJECTIVES

The aim of this qualitative study was to determine which clinical and contextual factors have a significant impact on antibiotic therapy (ABT) in pediatric patients with RTIs.

MATERIALS AND METHODS

An online survey was developed and carried out in Germany in cooperation with the Federal Association of Pediatricians and the German Society for Pediatric Infectious Diseases. Pediatricians and general practitioners were invited to participate.

RESULTS

The survey yielded 555 complete response data sets. Diagnostic uncertainty, time constraints for repeated consultations, and fear of complications were identified by 50% of both medical specialties as contextual factors fostering ABT. The risk of serious complications (e.g., mastoiditis) was overestimated by the majority of participants. More than 40% of respondents lacked knowledge concerning official guidelines, and RTIs with fever lasting longer than three days appeared to be an important criterion for ABT for 30-40%. Fewer than 60% of physicians were using a point-of-care device to determine C‑reactive protein.

CONCLUSION

Although most participants acknowledged the growing prevalence of antibiotic-resistant pathogens as an important problem, this survey identifies targets for ABS in pediatric outpatients with RTIs. Ongoing education and training (e.g., better communication strategies in response to parental concerns) should become mandatory for those who prescribe ABT for children with RTIs.

Antibiotic prescribing for respiratory tract complaints in Malta: a 1 year repeated cross-sectional surveillance study

OBJECTIVES

To determine the 1 year antibiotic prescribing patterns by GPs for acute respiratory tract complaints (aRTCs) in Malta.

METHODS

In this repeated cross-sectional surveillance study, GPs collected data for patients seen for aRTCs during a designated 1 week period each month, between May 2015 and April 2016. GPs received three text reminders during surveillance weeks and were contacted by phone at most four times during the year. GPs also received 3 monthly individual- and aggregate-level feedback reports on their antibiotic prescribing patterns. Descriptive statistics were used to examine patient, consultation and clinical characteristics, and to describe GPs' prescribing patterns.

RESULTS

Participating GPs (n = 33) registered 4641 patients with an aRTC, of whom 2122 (45.7%) received an antibiotic prescription. The majority (99.6%) of antibiotics prescribed were broad-spectrum and the most commonly prescribed antibiotics were macrolides (35.5%), followed by penicillins with a β-lactamase inhibitor (33.2%) and second-generation cephalosporins (14.2%). Specifically, co-amoxiclav (33.2%), clarithromycin (19.6%), azithromycin (15.1%) and cefuroxime axetil (10.9%) represented 78.8% of all antibiotics prescribed. Patients with tonsillar exudate (99.1%), purulent sputum (84%), otorrhoea (78%), tender cervical nodes (74.4%) and fever (73.1%) received most antibiotics. The diagnoses that received the highest proportion of antibiotic treatment were tonsillitis (96.3%), otitis media (92.5%) and bronchitis (87.5%). Wide variation in the choice of antibiotic class by diagnosis was observed.

CONCLUSIONS

GP antibiotic prescribing in Malta is high. The abundant use of broad-spectrum antibiotics, particularly macrolides, is of particular concern and indicates that antibiotics are being used inappropriately. Efforts must be made to improve GP awareness of appropriate antibiotic prescribing.

Is sharing the TARGET respiratory tract infection leaflet feasible in routine general practice to improve patient education and appropriate antibiotic use? A mixed methods study in England with patients and healthcare professionals

BACKGROUND

Patient education on treatment choices for common respiratory tract infections (RTIs) is important to encourage appropriate antibiotic use. Evidence shows that use of leaflets about RTIs can help reduce antibiotic prescribing. TARGET leaflets facilitate patient-clinician communication in consultations.

AIM

To explore patient, healthcare professional (HCP) and general practice (GP) staff views on the current Treating Your Infection (TYI)-RTI leaflet and proposed new 'antibiotic effect' column aimed at sharing information on the limited effect antibiotics have on the duration of RTIs.

METHODS

Service evaluation underpinned by Com-B behavioural framework, using patient and HCP questionnaires, and GP staff interviews/focus groups.

RESULTS

Patients completed 83 questionnaires in GP waiting rooms. A lack of patient understanding about usual illness duration influenced their use of antibiotics for some RTIs. Patients provided positive feedback about the leaflet, reporting it increased their capability to self-care, re-consult when necessary and increase understanding of illness duration. Patients indicated they would value information on the difference antibiotics can make to illness duration. In total, 43 HCP questionnaires were completed and 16 GP staff participated in interviews/focus groups. Emerging themes included: barriers and facilitators to leaflet use; modifications; and future dissemination of the leaflet. GP staff stated that the 'antibiotic effect' column should not be included in the leaflet.

CONCLUSION

Patient education around usual illness duration, side effects of antibiotics and back-up prescriptions gives patients a greater control of their infection management. As GP staff opposed the extra information about benefits of antibiotics on illness duration, this will not be added.

Public understanding and use of antibiotics in England: findings from a household survey in 2017

OBJECTIVES

To describe public understanding and use of antibiotics.

DESIGN

Ipsos MORI Capibus survey of randomly-selected households.

SETTING

England, January-April 2017.

PARTICIPANTS

2283 adults (≥15 years) including 777 parents of children <5 years old.

DATA COLLECTION AND ANALYSIS

The main survey was undertaken in January 2017 (n=1691); data from an additional sample of parents were collected in April 2017 (n=592). Analyses were weighted to obtain estimates representative of the population.

MAIN OUTCOME MEASURES

Responses to questions about antibiotics (awareness and perceptions), recent illness (expectations and experience), delayed and leftover antibiotics, and child illness stratified by demographic and socioeconomic characteristics.

RESULTS

Most respondents (83% (1404/1691)) recognised that antibiotics kill bacteria/treat bacterial infections, but a sizeable minority (35% (592/1691)) thought that antibiotics kill viruses/treat viral infections. Overall levels of understanding have not changed substantially since similar surveys in 2003 and 2008/2009. One sixth of respondents who were prescribed antibiotics reported having leftovers (14% (64/498)) and 33% (22/64) kept these for possible future use. 1.3% of all respondents (23/1691) reported taking left-over antibiotics in the past year and 1.6% (26/1691) reported taking antibiotics obtained without a prescription. Higher social grade and educational qualifications were strongly positively associated with antibiotic knowledge; youngest (15-24 years), oldest (65 +years) and black, Asian and minority ethnic adults were less knowledgeable. Among 1319 respondents who had an infection or antibiotics within the past year, 43% (568/1319) said that they had not received any advice or information about antibiotics.

CONCLUSIONS

Despite many campaigns, public understanding of antibiotics in England continues to combine correct basic knowledge held by most people with less prevalent but persistent and potentially harmful misunderstandings. These could be addressed through active provision of advice and information during primary and secondary care consultations and more effective public health interventions.

C-Reactive Protein Testing to Guide Antibiotic Prescribing for COPD Exacerbations

BACKGROUND

Point-of-care testing of C-reactive protein (CRP) may be a way to reduce unnecessary use of antibiotics without harming patients who have acute exacerbations of chronic obstructive pulmonary disease (COPD).

METHODS

We performed a multicenter, open-label, randomized, controlled trial involving patients with a diagnosis of COPD in their primary care clinical record who consulted a clinician at 1 of 86 general medical practices in England and Wales for an acute exacerbation of COPD. The patients were assigned to receive usual care guided by CRP point-of-care testing (CRP-guided group) or usual care alone (usual-care group). The primary outcomes were patient-reported use of antibiotics for acute exacerbations of COPD within 4 weeks after randomization (to show superiority) and COPD-related health status at 2 weeks after randomization, as measured by the Clinical COPD Questionnaire, a 10-item scale with scores ranging from 0 (very good COPD health status) to 6 (extremely poor COPD health status) (to show noninferiority).

RESULTS

A total of 653 patients underwent randomization. Fewer patients in the CRP-guided group reported antibiotic use than in the usual-care group (57.0% vs. 77.4%; adjusted odds ratio, 0.31; 95% confidence interval [CI], 0.20 to 0.47). The adjusted mean difference in the total score on the Clinical COPD Questionnaire at 2 weeks was -0.19 points (two-sided 90% CI, -0.33 to -0.05) in favor of the CRP-guided group. The antibiotic prescribing decisions made by clinicians at the initial consultation were ascertained for all but 1 patient, and antibiotic prescriptions issued over the first 4 weeks of follow-up were ascertained for 96.9% of the patients. A lower percentage of patients in the CRP-guided group than in the usual-care group received an antibiotic prescription at the initial consultation (47.7% vs. 69.7%, for a difference of 22.0 percentage points; adjusted odds ratio, 0.31; 95% CI, 0.21 to 0.45) and during the first 4 weeks of follow-up (59.1% vs. 79.7%, for a difference of 20.6 percentage points; adjusted odds ratio, 0.30; 95% CI, 0.20 to 0.46). Two patients in the usual-care group died within 4 weeks after randomization from causes considered by the investigators to be unrelated to trial participation.

CONCLUSIONS

CRP-guided prescribing of antibiotics for exacerbations of COPD in primary care clinics resulted in a lower percentage of patients who reported antibiotic use and who received antibiotic prescriptions from clinicians, with no evidence of harm. (Funded by the National Institute for Health Research Health Technology Assessment Program; PACE Current Controlled Trials number, ISRCTN24346473.).

How to avoid the inappropriate use of antibiotics in upper respiratory tract infections? A position statement from an expert panel

INTRODUCTION

Bacterial resistance burden has increased in the past years, mainly due to inappropriate antibiotic use. Recently it has become an urgent public health concern due to its impact on the prolongation of hospitalization, an increase of total cost of treatment and mortality associated with infectious disease. Almost half of the antimicrobial prescriptions in outpatient care visits are prescribed for acute upper respiratory infections, especially rhinosinusitis, otitis media, and pharyngotonsillitis. In this context, otorhinolaryngologists play an important role in orienting patients and non-specialists in the utilization of antibiotics rationally and properly in these infections.

OBJECTIVES

To review the most recent recommendations and guidelines for the use of antibiotics in acute otitis media, acute rhinosinusitis, and pharyngotonsillitis, adapted to our national reality.

METHODS

A literature review on PubMed database including the medical management in acute otitis media, acute rhinosinusitis, and pharyngotonsillitis, followed by a discussion with a panel of specialists.

RESULTS

Antibiotics must be judiciously prescribed in uncomplicated acute upper respiratory tract infections. The severity of clinical presentation and the potential risks for evolution to suppurative and non-suppurative complications must be taken into 'consideration'.

CONCLUSIONS

Periodic revisions on guidelines and recommendations for treatment of the main acute infections are necessary to orient rationale and appropriate use of antibiotics. Continuous medical education and changes in physicians' and patients' behavior are required to modify the paradigm that all upper respiratory infection needs antibiotic therapy, minimizing the consequences of its inadequate and inappropriate use.

Using theory to explore facilitators and barriers to delayed prescribing in Australia: a qualitative study using the Theoretical Domains Framework and the Behaviour Change Wheel

BACKGROUND

Delayed antibiotic prescribing reduces antibiotic use for acute respiratory infections in trials in general practice, but the uptake in clinical practice is low. The aim of the study was to identify facilitators and barriers to general practitioners' (GPs') use of delayed prescribing and to gain pharmacists' and the public's views about delayed prescribing in Australia.

METHODS

This study used the Theoretical Domains Framework and the Behaviour Change Wheel to explore facilitators and barriers to delayed prescribing in Australia. Forty-three semi-structured, face-to-face interviews with general practitioners, pharmacists and patients were conducted. Responses were coded into domains of the Theoretical Domains Framework, and specific criteria from the Behaviour Change Wheel were used to identify which domains were relevant to increasing the use of delayed prescribing by GPs.

RESULTS

The interviews revealed nine key domains that influence GPs' use of delayed prescribing: knowledge; cognitive and interpersonal skills; memory, attention and decision-making processes; optimism; beliefs about consequences; intentions; goals; emotion; and social influences: GPs knew about delayed prescribing; however, they did not use it consistently, preferring to bring patients back for review and only using it with patients in a highly selective way. Pharmacists would support GPs and the public in delayed prescribing but would fill the prescription if people insisted. The public said they would delay taking their antibiotics if asked by their GP and given the right information on managing symptoms and when to take antibiotics.

CONCLUSIONS

Using a theory-driven approach, we identified nine key domains that influence GPs' willingness to provide a delayed prescription to patients with an acute respiratory infection presenting to general practice. These data can be used to develop a structured intervention to change this behaviour and thus reduce antibiotic use for acute respiratory infections in general practice.