Impact of vaccination on antibiotic usage: a systematic review and meta-analysis

The role of vaccines in reducing antimicrobial resistance: A review of potential impact of vaccines on AMR and insights across 16 vaccines and pathogens

In 2019, an estimated 4.95 million deaths were linked to antimicrobial resistance (AMR). Vaccines can prevent many of these deaths by averting both drug-sensitive and resistant infections, reducing antibiotic usage, and lowering the likelihood of developing resistance genes. However, their role in mitigating AMR is currently underutilized. This article builds upon previous research that utilizes Vaccine Value Profiles-tools that assess the health, socioeconomic, and societal impact of pathogens-to inform vaccine development. We analyze the effects of 16 pathogens, covered by Vaccine Value Profiles, on AMR, and explore how vaccines could reduce AMR. The article also provides insights into vaccine development and usage. Vaccines are crucial in lessening the impact of infectious diseases and curbing the development of AMR. To fully realize their potential, vaccines must be more prominently featured in the overall strategy to combat AMR. This requires ongoing investment in research and development of new vaccines and the implementation of additional prevention and control measures to address this global threat effectively.

The Effect of COVID-19 Vaccination on Outpatient Antibiotic Prescribing in Older Adults: A Self-Controlled Risk-Interval Study

BACKGROUND

Coronavirus disease 2019 (COVID-19) vaccination has been associated with reduced outpatient antibiotic prescribing among older adults with laboratory-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We assessed the impact of COVID-19 vaccination on outpatient antibiotic prescribing in the broader population of older adults, regardless of SARS-CoV-2 infection status.

METHODS

We included adults aged ≥65 years who received their first, second, and/or third COVID-19 vaccine dose from December 2020 to December 2022. We used a self-controlled risk-interval design and included cases who received an antibiotic prescription 2-6 weeks before vaccination (pre-vaccination or control interval) or after vaccination (post-vaccination or risk interval). We used conditional logistic regression to estimate the odds of being prescribed (1) any antibiotic, (2) a typical "respiratory" infection antibiotic, or (3) a typical "urinary tract" infection antibiotic (negative control) in the post-vaccination interval versus the pre-vaccination interval. We accounted for temporal changes in antibiotic prescribing using background monthly antibiotic prescribing counts.

RESULTS

469 923 vaccine doses met inclusion criteria. The odds of receiving any antibiotic or a respiratory antibiotic prescription were lower in the post-vaccination versus pre-vaccination interval (aOR, .973; 95% CI, .968-.978; aOR, .961; 95% CI, .953-.968, respectively). There was no association between vaccination and urinary antibiotic prescriptions (aOR, .996; 95% CI, .987-1.006). Periods with high (>10%) versus low (<5%) SARS-CoV-2 test positivity demonstrated greater reductions in antibiotic prescribing (aOR, .875; 95% CI, .845-.905; aOR, .996; 95% CI, .989-1.003, respectively).

CONCLUSIONS

COVID-19 vaccination was associated with reduced outpatient antibiotic prescribing in older adults, especially during periods of high SARS-CoV-2 circulation.

In silico exploration of phenolics as modulators of penicillin binding protein (PBP) 2× of Streptococcus pneumoniae

Infections caused by multidrug-resistant Streptococcus pneumoniae remain the leading cause of pneumonia-related deaths in children < 5 years globally, and mutations in penicillin-binding protein (PBP) 2 × have been identified as the major cause of resistance in the organism to beta-lactams. Thus, the development of new modulators with enhanced binding of PBP2x is highly encouraged. In this study, phenolics, due to their reported antibacterial activities, were screened against the active site of PBP2x using structure-based pharmacophore and molecular docking techniques, and the ability of the top-hit phenolics to inhibit the active and allosteric sites of PBP2x was refined through 120 ns molecular dynamic simulation. Except for gallocatechin gallate and lysidicichin, respectively, at the active and allosteric sites of PBP2x, the top-hit phenolics had higher negative binding free energy (ΔGbind) than amoxicillin [active site (- 19.23 kcal/mol), allosteric site (- 33.75 kcal/mol)]. Although silicristin had the best broad-spectrum effects at the active (- 38.41 kcal/mol) and allosteric (- 50.54 kcal/mol) sites of PBP2x, the high thermodynamic entropy (4.90 Å) of the resulting complex might suggest the need for its possible structural refinement for enhanced potency. Interestingly, silicristin had a predicted synthetic feasibility score of < 5 and quantum calculations using the DFT B3LYP/6-31G+ (dp) revealed that silicristin is less stable and more reactive than amoxicillin. These findings point to the possible benefits of the top-hit phenolics, and most especially silicristin, in the direct and synergistic treatment of infections caused by S. pneumoniae. Accordingly, silicristin is currently the subject of further confirmatory in vitro research.

The burden of recurrent respiratory tract infections in adult population: a population-based study in primary care

BACKGROUND

Viral infections are the main original cause of recurrent respiratory tract infections (RRTIs), but their complications and recurrences are due to bacteria as well. While some operational definitions and epidemiology of RRTIs are reported in paediatrics, no similar definitions have been proposed for adults.

AIM

To assess the epidemiology and characteristics of RRTIs in the adult population.

DESIGN AND SETTING

Cohort study in the primary care setting.

METHODS

Using the Health Search Database, we selected a cohort of patients aged 18 years or older between 2002 and 2022. Yearly, we counted upper and lower respiratory tract infections (RTIs) per patient. We investigated 2 cut-offs defining RRTIs, nominally 3+ RRTIs/patient/year or greater than the mean value of RTIs/patient/year. The associations between these two event definitions and the correlates defining the patients' vulnerability were assessed by estimating a logistic regression model.

RESULTS

Over the study years, the mean number of RTIs/patient/year ranged from 0.07-0.16 or 1.10-1.13 events, when the denominator was formed by the overall population or those diagnosed with RTIs, respectively. When the analysis was focussed on 2022, we obtained 0.2% (1.3% among those with RTIs) or 13% (11.3% among those with RTIs) cases of RRTIs, using a cut-off of 3+ or >=0.16 events (mean value/patient), respectively. Consistent associations were found for these two operational definitions and the investigated clinical correlates.

CONCLUSION

We provided evidence on the epidemiology and concurrent/predisposing factors of RRTIs in adults. These data should support health authorities and general practitioners for the application of the most appropriate preventive and/or treatment strategies.

Identifying and addressing barriers and opportunities for bovine respiratory disease complex vaccination: a consensus paper on practical recommendations for best practise vaccination

Many questions are raised, and challenges faced in the new era of (intranasal) bovine respiratory disease complex vaccination. An increase in vaccination rate is expected, due to its positive impact on cattle health, reduction of antimicrobial use and economic factors. However, engagement of farmers and veterinarians with regard to vaccination is often affected by limitations, resulting in the development of barriers to vaccination, but also opportunities to overcome these. The objective of the report is to provide practical recommendations and a consensus on best practises for BRDC vaccination, addressing barriers faced by veterinarians and farmers. The report combines an evidence review with expert opinions and includes discussions on different vaccination approaches, such as intranasal and systemic protocols. As result of the discussions, several barriers to BRDC vaccination were identified, including a lack of knowledge or visibility of the disease's impact, the preference for blanket antibiotic use over vaccination, resistance to change, the need for visible success, uncertainty about the best time to vaccinate, and concerns about adverse reactions and vaccine efficacy in the presence of maternal antibodies. While these barriers seem substantial, they provide opportunities for the veterinary sector. Indeed, veterinarians are encouraged to use the argumentation presented, along with local case studies and diagnostic testing to highlight the impact of disease, while conducting calf health audits, ensuring expectations are managed to achieve visible success. Overall, this consensus paper aims to provide practical recommendations and support for veterinarians and farmers to overcome barriers and increase BRDC vaccination rates in cattle.

Drivers of Geographic Patterns in Outpatient Antibiotic Prescribing in the United States

In a retrospective, ecological analysis of US medical claims, visit rates explained more of the geographic variation in outpatient antibiotic prescribing rates than per-visit prescribing. Efforts to reduce antibiotic use may benefit from addressing the factors that drive higher rates of outpatient visits, in addition to continued focus on stewardship.

Assessing prescription of antibiotics after vaccination against pneumococcal pneumonia; using prescription sequence symmetry analysis

OBJECTIVES

Prescription sequence symmetry analysis (PSSA) is used to detect adverse event signals using administrative claims databases. In this study, we investigated whether PSSA can be applied to gauge the effects of PCV13 vaccination on antibiotic prescription rates in elderly patients.

METHODS

We studied prescription records of patients aged 65 or older between 1 January 2014 and 31 December 2020, from the Helsana Swiss claims database. PSSA was performed to explore the relationship between 13-valent pneumococcal conjugate vaccine (PCV13) and six antibiotics recommended by the Swiss Society of Infectious Diseases for community-acquired pneumonia treatment (amoxicillin-clavulanate, azithromycin, clarithromycin, doxycycline, levofloxacin, and moxifloxacin), three additional antibiotics (amoxicillin, ciprofloxacin, and fosfomycin), and ten control drugs.

RESULTS

Amoxicillin-clavulanate, clarithromycin, and levofloxacin were more likely to be prescribed before than after vaccination, for all time windows between 25 and 104 weeks. Adjusted sequence ratio (ASR) values ranged from 0.599 to 0.614, 0.508 to 0.568, and 0.514 to 0.752, respectively. Lower prescription rates after vaccination were also observed for azithromycin (all time windows between 38 and 104 weeks, ASR 0.705-0.739) and moxifloxacin (all time windows between 52 and 104 weeks, ASR 0.658-0.772). PCV13 did not have statistically significant associations with doxycycline, amoxicillin, ciprofloxacin, fosfomycin, or any of the ten controls.

DISCUSSION

The lower prescription rate of antibiotics for community-acquired pneumonia after vaccination could be attributed to a protective effect of PCV13. This novel application of PSSA can be used to compare the real-world impact of other vaccines on drug consumption.

Determinants of private-sector antibiotic consumption in India: findings from a quasi-experimental fixed-effects regression analysis using cross-sectional time-series data, 2011-2019

The consumption of antibiotics varies between and within countries. However, our understanding of the key drivers of antibiotic consumption is largely limited to observational studies. Using Indian data that showed substantial differences between states and changes over years, we conducted a quasi-experimental fixed-effects regression study to examine the determinants of private-sector antibiotic consumption. Antibiotic consumption decreased by 10.2 antibiotic doses per 1000 persons per year for every ₹1000 (US$12.9) increase in per-capita gross domestic product. Antibiotic consumption decreased by 46.4 doses per 1000 population per year for every 1% increase in girls' enrollment rate in tertiary education. The biggest determinant of private sector antibiotic use was government spending on health-antibiotic use decreased by 461.4 doses per 1000 population per year for every US$12.9 increase in per-capita government health spending. Economic progress, social progress, and increased public investment in health can reduce private-sector antibiotic use.

Predictors of vaccination card retention in Tamale Metropolis, Ghana

BACKGROUND

The home-based vaccination card is an important health record for determining vaccination status of children during surveys, particularly in low- and middle-income countries. However, there are limited evidence on the factors that influence its retention in Ghana. We assessed the predictors of vaccination card retention in Tamale Metropolis, Ghana.

METHODS

We conducted a cross-sectional study from 21st December 2022 to 10th January 2023 among children aged 0-59 months in the Tamale Metropolis. Multi-stage sampling was used to select caregivers of children aged 0-59 months for enrolment in the study. Data were collected using validated questionnaire through face-to-face interviews of caregivers. A vaccination card was retained if it was presented for physical inspection by research assistants. The factors that influence vaccination card retention were determined in a multivariate logistic regression analysis at p<0.05.

RESULTS

A total of 1,532 eligible children were enrolled in this study. Vaccination card retention was 91.5%. Negative predictors of card retention included: being resident in the Nyohini (AOR = 0.28; 95% CI = 0.15-0.50) and Tamale Central (AOR = 0.51; 95% CI = 0.29-0.90) sub-Metro areas and being caregivers of children aged 24-59 months (AOR = 0.39; 95% CI = 0.22-0.68). On the other hand, paying for the vaccination card (AOR = 5.14; 95% CI = 2.95-8.95) was a positive predictor of vaccination card retention.

CONCLUSION

In this study, vaccination card retention among children aged 0-59 months was higher than national estimates. Vaccination card retention was mainly influenced by sub-Metro area, age of child and mode of acquisition of the card such as out-of-pocket payment. There is need to design and deliver tailored messages including the importance of vaccination card retention to caregivers of children based on geographic context. Additionally, the policy on sale of vaccination cards should be revised to allow for cost sharing to enhance its retention.

Innovative Biomedical and Technological Strategies for the Control of Bacterial Growth and Infections

Antibiotics comprise one of the most successful groups of pharmaceutical products. Still, they have been associated with developing bacterial resistance, which has become one of the most severe problems threatening human health today. This context has prompted the development of new antibiotics or co-treatments using innovative tools to reverse the resistance context, combat infections, and offer promising antibacterial therapy. For the development of new alternatives, strategies, and/or antibiotics for controlling bacterial growth, it is necessary to know the target bacteria, their classification, morphological characteristics, the antibiotics currently used for therapies, and their respective mechanisms of action. In this regard, genomics, through the sequencing of bacterial genomes, has generated information on diverse genetic resources, aiding in the discovery of new molecules or antibiotic compounds. Nanotechnology has been applied to propose new antimicrobials, revitalize existing drug options, and use strategic encapsulating agents with their biochemical characteristics, making them more effective against various bacteria. Advanced knowledge in bacterial sequencing contributes to the construction of databases, resulting in advances in bioinformatics and the development of new antimicrobials. Moreover, it enables in silico antimicrobial susceptibility testing without the need to cultivate the pathogen, reducing costs and time. This review presents new antibiotics and biomedical and technological innovations studied in recent years to develop or improve natural or synthetic antimicrobial agents to reduce bacterial growth, promote well-being, and benefit users.

Association between seasonal influenza vaccination and antimicrobial use in Japan from the 2015-16 to 2020-21 seasons: from the VENUS study

BACKGROUND

Seasonal influenza vaccination might be considered an antimicrobial resistance (AMR) countermeasure because it can reduce unnecessary antimicrobial use for acute respiratory infection by mitigating the burden of such diseases.

OBJECTIVES

To examine the association between seasonal influenza vaccination and antimicrobial use (AMU) in Japan at the community level and to examine the impact of influenza vaccination on the frequency of unnecessary antimicrobial prescription for upper respiratory infection.

METHODS

For patients who visited any healthcare facility in one of the 23 wards of Tokyo, Japan, due to upper respiratory infection and who were aged 65 years or older, we extracted data from the Vaccine Effectiveness, Networking, and Universal Safety (VENUS) study database, which includes all claims data and vaccination records from the 2015-16 to 2020-21 seasons. We used the average treatment effect (ATE) with 1:1 propensity score matching to examine the association of vaccination status with frequency of antibiotic prescription, frequency of healthcare facility consultation, risk of admission and risk of death in the follow-up period of the same season (from 1 January to 31 March).

RESULTS

In total, 244 642 people were enrolled. Matched data included 101 734 people in each of the unvaccinated and vaccinated groups. The ATE of vaccination was -0.004 (95% CI -0.006 to -0.002) for the frequency of antibiotic prescription, -0.005 (-0.007 to -0.004) for the frequency of healthcare facility consultation, -0.001 (-0.002 to -0.001) for the risk of admission and 0.00 (0.00 to 0.00) for the risk of death.

CONCLUSIONS

Our results suggest that seasonal influenza vaccination is associated with lower frequencies of unnecessary antibiotic prescription and of healthcare facility consultation.

Dynamics of Pediatric Antibiotic Use Differ between High- and Low-Prescribing Clinics after Pneumococcal Conjugate Vaccines

OBJECTIVE

To compare dispensed oral antibiotic prescription rates (DAPRs) after implementation of pneumococcal conjugate vaccine (PCV) in high antibiotic-prescribing clinics (HPC) with low antibiotic-prescribing clinics (LPC) in 2 distinct ethnic groups of children (Jewish and Bedouin children) <5 years of age.

METHODS

Clinics with ≥50 insured children, active both pre-PCV (2005-2009) and post-PCV (2010-2018) implementation, were included. HPC and LPC were defined by DAPRs above or below the median in each age and ethnic group. Monthly dispensed antibiotic prescription rate (DAPR) trends (adjusted for age and ethnicity) were calculated using interrupted time series. Mean yearly incidence rate-ratios (late PCV13 vs pre-PCV) were calculated.

RESULTS

Bedouin HPC had the highest pre-PCV overall-DAPR per 1000 child-years ± SD (2520.4 ± 121.2), followed by Jewish HPC (1885.5 ± 47.6), Bedouin LPC (1314.8 ± 81.6), and Jewish LPC (996.0 ± 19.6). Shortly after PCV implementation, all DAPRs and amoxicillin/amoxicillin-clavulanate DAPRs declined in all groups except Jewish LPC, stabilizing within 4-5 years post-PCV. The rates and magnitudes of declines were directly proportional to the pre-PCV DAPR magnitudes, achieving near-complete closure of the pre-PCV DAPR gaps between the 4 groups (rates during late-PCV13 ranging from 1649.4 ± 23.5 [Bedouin HPC] to 1200.3 ± 72.4 [Jewish LPC]).

CONCLUSIONS

PCVs are a powerful tool in reducing outpatient antibiotic consumption among young children, especially in HPC, resulting in partial closure of DAPR gap between HPC and LPC. The higher impact on HPC suggests that PCV-associated declines of respiratory disease may strongly contribute to a judicious antibiotic approach in clinics with high antibiotic consumption.

Empowering Low- and Middle-Income Countries to Combat AMR by Minimal Use of Antibiotics: A Way Forward

Antibiotic overuse poses a critical global health concern, especially in low- and middle-income countries (LMICs) where access to quality healthcare and effective regulatory frameworks often fall short. This issue necessitates a thorough examination of the factors contributing to antibiotic overuse in LMICs, including weak healthcare infrastructure, limited access to quality services, and deficiencies in diagnostic capabilities. To address these challenges, regulatory frameworks should be implemented to restrict non-prescription sales, and accessible point-of-care diagnostic tools must be emphasized. Furthermore, the establishment of effective stewardship programs, the expanded use of vaccines, and the promotion of health systems, hygiene, and sanitation are all crucial components in combating antibiotic overuse. A comprehensive approach that involves collaboration among healthcare professionals, policymakers, researchers, and educators is essential for success. Improving healthcare infrastructure, enhancing access to quality services, and strengthening diagnostic capabilities are paramount. Equally important are education and awareness initiatives to promote responsible antibiotic use, the implementation of regulatory measures, the wider utilization of vaccines, and international cooperation to tackle the challenges of antibiotic overuse in LMICs.

The Role of Adult Vaccines as Part of Antimicrobial Stewardship: A Scoping Review

BACKGROUND

Antimicrobial resistance (AMR) is a significant global health concern, causing an estimated 700,000 deaths annually. Although immunisation has been shown to significantly reduce AMR, the role of vaccines as part of antimicrobial stewardship (AMS) practices is often overlooked.

OBJECTIVE

To identify and examine the available literature on the role of vaccines as part of AMS practices.

METHOD

A scoping review was conducted in the following databases: MEDLINE, Embase, Scopus, CINAHL, CCRCT, IPA, and WoS, along with grey literature sources. The review was conducted using the JBI Methodology for Scoping Reviews and reported in line with the PRISMA-SCr checklist.

RESULTS

Among the 1711 records identified, 34 met the inclusion criteria; 8 discussed only the concept, while 26 discussed both the concept and the vaccine implementation method in AMS practices. There were eight recommended and/or utilised types of AMS activities identified involving vaccines, under four key themes of vaccine-related AMS strategies: Education, Screening, Vaccination, and Monitoring. Influenza and pneumococcal vaccines had the most evidence for inclusion.

CONCLUSION

Overall, the evidence supports the role of vaccines as part of AMS practices and the value of their inclusion in creating improved and comprehensive AMS strategies to further combat the development of AMR.

The effect of a comprehensive typhoid conjugate vaccine campaign on antimicrobial prescribing in children in Harare, Zimbabwe: a mixed methods study

BACKGROUND

Vaccines prevent infections and could subsequently reduce antimicrobial use. A 1-week mass vaccination campaign was done with Typbar-TCV (Bharat Biotech, Hyderabad, India) between Feb 25 and March 4, 2019. We investigated whether this typhoid conjugate vaccine campaign could affect antimicrobial prescribing in children presenting to primary care in Harare, Zimbabwe.

METHODS

In this mixed methods study, data for acute paediatric outpatient consultations between Jan 1, 2018, and March 31, 2020, were collected from five clinics in Harare. Interrupted time series analysis was done to compare prescription data before and after the campaign. To contextualise findings, qualitative data were collected between April 20, 2021, and July 20, 2022, comprising ethnographic research (ie, workshops, surveys, observations, and interviews) in 14 clinics. Ethnographic data were used for thematic analysis. The primary outcome was monthly antimicrobial prescriptions in children aged 6 months to 15 years, normalised by the number of trauma events in all age groups.

FINDINGS

In the data collection period, 27 107 paediatric consultations were recorded. 17 951 (66·2%) of 27 107 children were prescribed antimicrobials. Despite the perceived reduction in typhoid cases and a decreasing trend in the prescription of antimicrobials commonly used to treat typhoid (ie, ciprofloxacin and azithromycin), mass vaccination with Typbar-TCV did not affect the total rate of antimicrobials (adjusted rate ratio, 1·20, 95% CI 0·70-2·05, p=0·51) or the rate of typhoid antimicrobials prescribed (0·93, 0·44-1·96, p=0·85). Unsafe water sources and insufficient diagnostic services were reported to contribute to the continued disease burden and antimicrobial prescription.

INTERPRETATION

Non-specific febrile illness caused by confirmed or suspected typhoid is a common cause of antimicrobial use in endemic areas. Although effective in preventing typhoid fever, we were unable to identify any effect of Typbar-TCV on antimicrobial prescribing. Ethnographic research showed the effect of contextual factors on antimicrobial prescribing, including concerns regarding safe water access, appropriate sewage disposal, health-care and diagnostic availability. To realise effects beyond disease burden reduction, holistic approaches addressing these concerns are needed so that the value of vaccines mitigating the effects of antimicrobial use as a driver of antimicrobial resistance is fully achieved.

FUNDING

Wellcome Trust.

TRANSLATION

For the Shona translation of the abstract see Supplementary Materials section.

Coronavirus Disease 2019 Vaccination Is Associated With Reduced Outpatient Antibiotic Prescribing in Older Adults With Confirmed Severe Acute Respiratory Syndrome Coronavirus 2: A Population-Wide Cohort Study

BACKGROUND

Antibiotics are frequently prescribed unnecessarily in outpatients with coronavirus disease 2019 (COVID-19). We sought to evaluate factors associated with antibiotic prescribing in outpatients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

METHODS

We performed a population-wide cohort study of outpatients aged ≥66 years with polymerase chain reaction-confirmed SARS-CoV-2 from 1 January 2020 to 31 December 2021 in Ontario, Canada. We determined rates of antibiotic prescribing within 1 week before (prediagnosis) and 1 week after (postdiagnosis) reporting of the positive SARS-CoV-2 result, compared to a self-controlled period (baseline). We evaluated predictors of prescribing, including a primary-series COVID-19 vaccination, in univariate and multivariable analyses.

RESULTS

We identified 13 529 eligible nursing home residents and 50 885 eligible community-dwelling adults with SARS-CoV-2 infection. Of the nursing home and community residents, 3020 (22%) and 6372 (13%), respectively, received at least 1 antibiotic prescription within 1 week of a SARS-CoV-2 positive result. Antibiotic prescribing in nursing home and community residents occurred, respectively, at 15.0 and 10.5 prescriptions per 1000 person-days prediagnosis and 20.9 and 9.8 per 1000 person-days postdiagnosis, higher than the baseline rates of 4.3 and 2.5 prescriptions per 1000 person-days. COVID-19 vaccination was associated with reduced prescribing in nursing home and community residents, with adjusted postdiagnosis incidence rate ratios (95% confidence interval) of 0.7 (0.4-1) and 0.3 (0.3-0.4), respectively.

CONCLUSIONS

Antibiotic prescribing was high and with little or no decline following SARS-CoV-2 diagnosis but was reduced in COVID-19-vaccinated individuals, highlighting the importance of vaccination and antibiotic stewardship in older adults with COVID-19.

The impact of influenza and pneumococcal vaccination on antibiotic use: an updated systematic review and meta-analysis

BACKGROUND

Vaccination can prevent bacterial and viral infections that could otherwise increase the chances of receiving (unnecessary) antibiotic treatment(s). As a result, vaccination may provide an important public health intervention to control antimicrobial resistance (AMR).

OBJECTIVES

Perform a systematic literature review to better understand the impact of influenza, pneumococcal and COVID-19 vaccination on antibiotic use, and to identify differences in effect between world regions and study designs.

METHODS

We performed a systematic literature review and meta-analysis which updated previous literature reviews with new data from 1 October 2018 to 1 December 2021. The study focuses on randomised controlled trials (RCTs) and observational studies. Results from the meta-analysis of RCTs were stratified by WHO region and age group. Vote counting based on the direction of effect was applied to synthesize the results of the observational studies.

RESULTS

Most studies are performed in the WHO European Region and the Region of the Americas in high-income countries. RCTs show that the effect of influenza vaccination on the number of antibiotic prescriptions or days of antibiotic use (Ratio of Means (RoM) 0.71, 95% CI 0.62-0.83) is stronger compared to the effect of pneumococcal vaccination (RoM 0.92, 95% CI 0.85-1.00). These studies also confirm a reduction in the proportion of people receiving antibiotics after influenza vaccination (Risk Ratio (RR) 0.63, 95% CI 0.51-0.79). The effect of influenza vaccination in the European and American regions ranged from RoM 0.63 and 0.87 to RR 0.70 and 0.66, respectively. The evidence from observational studies supports these findings but presents a less consistent picture. No COVID-19 studies were identified.

CONCLUSION

We find that both RCTs and observational studies show that influenza vaccination significantly reduces antibiotic use, while the effect of pneumococcal vaccination is less pronounced. We were unable to study the effect of COVID-19 vaccination and no clear regional patterns were found due to the high heterogeneity between studies. Overall, our data supports the use of influenza vaccination as an important public health intervention to reduce antibiotic use and possibly control AMR.

How can we tackle the overuse of antibiotics in low- and middle-income countries?

INTRODUCTION

Antibiotic overuse is a pressing global health concern, particularly in low- and middle-income countries (LMICs) where there is limited access to quality healthcare and insufficient regulation of antibiotic dispensation. This perspective piece highlights the challenges of antibiotic overuse in LMICs and provides insights into potential solutions to address this issue.

AREAS COVERED

This perspective explores key factors contributing to antibiotic overuse in LMICs, encompassing weak healthcare infrastructure, limited access to quality services, and deficiencies in diagnostic capabilities. It discusses regulatory frameworks to curb non-prescription sales, the role of accessible point-of-care diagnostic tools, challenges in implementing effective stewardship programs, the expanded use of vaccines, and the importance of health systems, hygiene, and sanitation.

EXPERT OPINION

In this article, we emphasize the need for a comprehensive approach involving collaboration among healthcare professionals, policymakers, researchers, and educators. We underscore the importance of improving healthcare infrastructure, enhancing access to quality services, and strengthening diagnostic capabilities. The article also highlights the significance of education and awareness in promoting responsible antibiotic use, the role of regulatory measures, the expanded utilization of vaccines, and the need for international collaboration to address the challenges of antibiotic overuse in LMICs.

Global and regional burden of attributable and associated bacterial antimicrobial resistance avertable by vaccination: modelling study

INTRODUCTION

Antimicrobial resistance (AMR) is a global health threat with 1.27 million and 4.95 million deaths attributable to and associated with bacterial AMR, respectively, in 2019. Our aim is to estimate the vaccine avertable bacterial AMR burden based on existing and future vaccines at the regional and global levels by pathogen and infectious syndromes.

METHODS

We developed a static proportional impact model to estimate the vaccination impact on 15 bacterial pathogens in terms of reduction in age-specific AMR burden estimates for 2019 from the Global Research on Antimicrobial Resistance project in direct proportion to efficacy, coverage, target population for protection, and duration of protection of existing and future vaccines.

RESULTS

The AMR burden avertable by vaccination in 2019 was highest for the WHO Africa and South-East Asia regions, for lower respiratory infections, tuberculosis, and bloodstream infections by infectious syndromes, and for Mycobacterium tuberculosis and Streptococcus pneumoniae by pathogen. In the baseline scenario for vaccination of primary age groups against 15 pathogens, we estimated vaccine-avertable AMR burden of 0.51 (95% UI 0.49-0.54) million deaths and 28 (27-29) million disability-adjusted life-years (DALYs) associated with bacterial AMR, and 0.15 (0.14-0.17) million deaths and 7.6 (7.1-8.0) million DALYs attributable to AMR globally in 2019. In the high-potential scenario for vaccination of additional age groups against seven pathogens, we estimated vaccine-avertable AMR burden of an additional 1.2 (1.18-1.23) million deaths and 37 (36-39) million DALYs associated with AMR, and 0.33 (0.32-0.34) million deaths and 10 (9.8-11) million DALYs attributable to AMR globally in 2019.

CONCLUSION

Increased coverage of existing vaccines and development of new vaccines are effective means to reduce AMR, and this evidence should inform the full value of vaccine assessments.

Cost-effectiveness of the adjuvanted quadrivalent influenza vaccine in the elderly Belgian population

BACKGROUND

Between 2015 and 2019, when 62% of Belgian adults aged ≥ 65 years were vaccinated with standard quadrivalent influenza vaccines, influenza caused an average of 3,905 hospitalizations and 347 premature deaths per year in older adults. The objective of the present analysis was to estimate the cost-effectiveness of the adjuvanted quadrivalent influenza vaccine (aQIV) compared to the standard (SD-QIV) and high-dose (HD-QIV) vaccines in elderly Belgians.

RESEARCH DESIGN AND METHODS

The analysis was based on a static cost-effectiveness model that captured the evolution of patients infected with influenza and was customized with available national data.

RESULTS

Vaccinating adults aged ≥ 65 years with aQIV instead of SD-QIV would decrease the number of hospitalizations by 530 and the number of deaths by 66 in the 2023-2024 influenza season. aQIV was cost-effective compared to SD-QIV with an incremental cost of €15,227/quality-adjusted life year (QALY). aQIV is cost-saving when compared to HD-QIV in the subgroup of institutionalized elderly adults who were granted reimbursement for this vaccine.

CONCLUSION

In a health care system striving to improve the prevention of infectious diseases, a cost-effective vaccine such as aQIV is a key asset to reduce the number of influenza-related hospitalizations and premature deaths in older adults.

PLAIN LANGUAGE SUMMARY

A flu vaccine containing a unique immune boosting additive reduces medical spending by reducing flu hospitalizations and early deaths in the elderly.

Cross-sectional health centre and community-based evaluation of the impact of pneumococcal and malaria vaccination on antibiotic prescription and usage, febrile illness and antimicrobial resistance in young children in Malawi: the IVAR study protocol

INTRODUCTION

Vaccination is a potentially critical component of efforts to arrest development and dissemination of antimicrobial resistance (AMR), though little is known about vaccination impact within low-income and middle-income countries. This study will evaluate the impact of vaccination on reducing carriage prevalence of resistant Streptococcus pneumoniae and extended spectrum beta-lactamase-producing Escherichia coli and Klebsiella species. We will leverage two large ongoing cluster-randomised vaccine evaluations in Malawi assessing; first, adding a booster dose to the 13-valent pneumococcal conjugate vaccine (PCV13) schedule, and second, introduction of the RTS,S/AS01 malaria vaccine.

METHODS AND ANALYSIS

Six cross-sectional surveys will be implemented within primary healthcare centres (n=3000 users of outpatient facilities per survey) and their local communities (n=700 healthy children per survey): three surveys in Blantyre district (PCV13 component) and three surveys in Mangochi district (RTS,S/AS01 component). We will evaluate antibiotic prescription practices and AMR carriage in children ≤3 years. For the PCV13 component, surveys will be conducted 9, 18 and 33 months following a 3+0 to 2+1 schedule change. For the RTS,S/AS01 component, surveys will be conducted 32, 44 and 56 months post-RTS,S/AS01 introduction. Six health centres in each study component will be randomly selected for study inclusion. Between intervention arms, the primary outcome will be the difference in penicillin non-susceptibility prevalence among S. pneumoniae nasopharyngeal carriage isolates in healthy children. The study is powered to detect an absolute change of 13 percentage points (ie, 35% vs 22% penicillin non-susceptibility).

ETHICS AND DISSEMINATION

This study has been approved by the Kamuzu University of Health Sciences (Ref: P01-21-3249), University College London (Ref: 18331/002) and University of Liverpool (Ref: 9908) Research Ethics Committees. Parental/caregiver verbal or written informed consent will be obtained prior to inclusion or recruitment in the health centre-based and community-based activities, respectively. Results will be disseminated via the Malawi Ministry of Health, WHO, peer-reviewed publications and conference presentations.

Using Typhoid Conjugate Vaccines to Prevent Disease, Promote Health Equity, and Counter Drug-Resistant Typhoid Fever

Typhoid fever is a serious disease that disproportionately impacts children in low-resource settings in sub-Saharan Africa, South and Southeast Asia, and the Western Pacific. The prevalence of antimicrobial-resistant strains of S. Typhi continue to increase worldwide. Two safe, effective, and cost-effective typhoid conjugate vaccines (TCVs) are World Health Organization-prequalified for the prevention of typhoid fever in children as young as 6 months. Typhoid conjugate vaccines have proven effectiveness in preventing drug-resistant S. Typhi and have been deployed successfully in outbreak response and routine immunization scenarios. Broad and equitable distribution of TCVs is essential to combat the spread and potentially devastating consequences of typhoid fever. It is vital to empower decision-makers in typhoid-endemic countries to introduce TCVs and for leaders to embrace this critical tool to prevent typhoid fever, slow the spread of drug-resistant S. Typhi strains, promote health equity, and save lives.

Impact of PCV10 on pediatric pneumococcal disease burden in Brazil: time for new recommendations?

OBJECTIVE

To describe the impact of the 10-valent pneumococcal conjugate vaccine on the pediatric burden of pneumococcal infections, carriage, serotype replacement, and antimicrobial resistance in Brazil since its introduction in 2010.

DATA SOURCE

A narrative review of English, Spanish, and Portuguese articles published in online databases and in Brazilian epidemiological surveillance databases was performed. The following keywords were used: Streptococcus pneumoniae, pneumococcal disease, conjugate vaccine, PCV10, antimicrobial resistance, and meningitis.

SUMMARY OF THE FINDINGS

Declines in hospitalization rates of all-cause pneumonia occurred in the target age groups and some age groups not targeted by vaccination early after the use of PCV10. Large descriptive studies of laboratory-confirmed pneumococcal meningitis and hospital-based historical series of hospitalized children with IPD have evidenced a significant impact on disease burden, in-hospital fatality rates, and admission to the intensive care unit before and after the inclusion of the vaccine. Impact data on otitis media is limited and inconsistent; the main benefit remains the prevention of complicated diseases. During the late post-vaccine years, a significant and progressive increase in high-level penicillin non-susceptibility pneumococci has been described. Since 2014 serotype 19A has been the leading serotype in all ages and was responsible for 28.2%-44.6% of all IPD in children under 5 yrs.

CONCLUSIONS

PCV10 has performed a significant impact on IPD in Brazil since 2010, however, progress has been continuously hampered by replacement. Broader spectrum PCVs could provide expanded direct and indirect protection against ST19A and other additional serotypes of increasing importance if administered to children in the Brazilian National Immunization Program.

Vaccines for a sustainable planet

The health of the planet is one objective of the United Nations' Sustainable Development Goals. Vaccines can affect not only human health but also planet health by reducing poverty, preserving microbial diversity, reducing antimicrobial resistance, and preventing an increase in pandemics that is fueled partly by climate change.

Pseudomonas aeruginosa PAO1 outer membrane vesicles-diphtheria toxoid conjugate as a vaccine candidate in a murine burn model

Pseudomonas aeruginosa is an opportunistic pathogen considered a common cause of nosocomial infection with high morbidity and mortality in burn patients. Immunoprophylaxis techniques may lower the mortality rate of patients with burn wounds infected by P. aeruginosa; consequently, this may be an efficient strategy to manage infections caused by this bacterium. Several pathogenic Gram-negative bacteria like P. aeruginosa release outer membrane vesicles (OMVs), and structurally OMV consists of several antigenic components capable of generating a wide range of immune responses. Here, we evaluated the immunogenicity and efficacy of P. aeruginosa PA-OMVs (PA-OMVs) conjugated with the diphtheria toxoid (DT) formulated with alum adjuvant (PA-OMVs-DT + adj) in a mice model of burn wound infection. ELISA results showed that in the group of mice immunized with PA-OMVs-DT + adj conjugated, there was a significant increase in specific antibodies titer compared to non-conjugated PA-OMVs or control groups. In addition, the vaccination of mice with PA-OMVs-DT + adj conjugated generated greater protective effectiveness, as seen by lower bacterial loads, and eightfold decreased inflammatory cell infiltration with less tissue damage in the mice burn model compared to the control group. The opsonophagocytic killing results confirmed that humoral immune response might be critical for PA-OMVs mediated protection. These findings suggest that PA-OMV-DT conjugated might be used as a new vaccine against P. aeruginosa in burn wound infection.

Economic evaluation of antimicrobial use practices in animal agriculture: a case of poultry farming

Background

The growing evidence of the contribution of antimicrobial use (AMU) in animal agriculture to the public health threat of antimicrobial resistance has highlighted to policymakers the importance of the need for prudent AMU in animal production. Livestock farming is an economic process, where farmers are using inputs such as antimicrobials to minimize their losses.

Objectives

Using a large and unique dataset combining time-series data on economic performance and health records in conventional broiler production in France, we identify how improved healthcare management and disease prevention impact economic performance, AMU reduction and health outcomes.

Methods

We analyse the main characteristics of the economic performance of farms measured by the profit per m², by performing advanced regression models investigating the relative importance of medication and veterinary procedures.

Results

In our study, 50% of the treatments (expressed as number of new treatments) are attributable to only 30% of all flocks. There is an inverted U-shaped relationship between AMU and economic performance. This finding implies that the marginal profit of antimicrobials is decreasing, meaning that using antimicrobials is only profitable up to a certain threshold. Results also show that the profit increases as the number of preventive treatments increase.

Conclusions

Our findings suggest that policies encouraging farmers to work upstream from the occurrence of disease have the potential to perform better than regulations, as they would maintain a profitable activity while diminishing AMU. Encouraging adequate infection control practices by subsidizing or providing other incentives would benefit farmers and society.

The approach of World Health Organization to articulate the role and assure impact of vaccines against antimicrobial resistance

Antimicrobial resistance (AMR) is a growing global problem and there were an estimated 4.95 million deaths associated with bacterial AMR worldwide in 2019. Vaccines can impact AMR by preventing infections and reducing the need for antibiotics which will inadvertently slow the emergence of AMR. Effective infection prevention and control (IPC) has been identified as the cornerstone action to combat AMR by the World Health Assembly and the Global Action plan on AMR. Similarly, the Immunization Agenda 2030 highlights vaccines as critical tools to combat AMR. This article summarizes the strategy of the World Health Organization to understand, articulate and communicate the important role of vaccines in countering AMR. The work is organized around developing a strategy, understanding the pipeline of vaccines in development, articulating the value of vaccines against AMR, and assuring sustainable impact of vaccines at a country level to combat AMR.

Evaluating the impact of Respiratory Syncytial Virus immunisation strategies on antibiotic use and drug resistant bacterial infections in England

Background: Vaccines against viruses have been proposed as a novel means to reduce antibiotic use, which would, in turn, decrease selection for antibiotic resistant bacteria. However, the impact of this intervention is poorly quantified, and likely depends on setting-specific epidemiology. Therefore, with increasing confidence in a new vaccine against respiratory syncytial virus (RSV), it is important to quantify the impact of these vaccines on antibiotic prescribing and any downstream reduction in drug resistant bacterial infections. Methods: Here we integrate results from a dynamic transmission model of RSV and a statistical attribution framework to capture the impact of RSV vaccines on the reduction in antibiotic prescribing due to averted primary care visits in England. Results: Under base case assumptions, we find that the most impactful RSV vaccine strategy targets children aged 5–14 years, resulting in an annual reduction of 10.9 (8.0–14.2) antibiotic courses per 10,000 person years across the entire population, equivalent to reducing annual all-cause primary care prescribing by 0.23%. Our results suggest that this reduction in antibiotic use would gain 130 disability-adjusted life years and avert £51,000 associated with drug resistant bacterial infections. Seasonally administering monoclonal antibodies (mAbs) to high-risk infants under 6 months is the most efficient strategy, reducing per person year antibiotic prescribing by 2.6 (1.9–3.3) antibiotic courses per 1,000 mAb courses. Conclusions: Under optimistic conditions, the cost-effectiveness of RSV vaccine strategies in England would likely not be altered by integrating the benefits of preventing drug resistant infections in addition to RSV disease prevention.

Assessment of the inclusion of vaccination as an intervention to reduce antimicrobial resistance in AMR national action plans: a global review

BACKGROUND

Vaccination can reduce antibiotic use by decreasing bacterial and viral infections and vaccines are highlighted in the WHO Global Action Plan on Antimicrobial Resistance (AMR) as an infection prevention measure to reduce AMR. Our study aimed to analyze whether WHO Member States have developed AMR national action plans that are aligned with the Global Action Plan regarding objectives on vaccination.

METHODS

We reviewed 77 out of 90 AMR national action plans available in the WHO library that were written after publication of the Global Action Plan in 2015. Each plan was analyzed using content analysis, with a focus on vaccination and key components as defined by WHO (I. Strategic plan (e.g. goals and objectives), II. Operational plan, III. Monitoring and Evaluation plan).

RESULTS

Vaccination was included in 67 of 77 AMR plans (87%) across all WHO Regions (Africa: n = 13/13, the Eastern Mediterranean: n = 15/16, Europe: n = 10/14, the Americas: n = 8/8, South-East Asia: n = 8/11, and the Western Pacific: n = 13/15). Pneumococcal and influenza vaccination were most frequently highlighted (n = 12 and n = 11). We found indications that vaccination objectives are more often included in AMR plans from higher income countries, while lower income countries more often include specific vaccines. The key WHO components of national action plans were frequently not covered (I. 47% included, II. 57%, III. 40%). In total, 33 countries (43%) included indicators (e.g. strategic objectives) to capture the role of vaccines against AMR.

CONCLUSIONS

While vaccination to reduce AMR is seen as an important global public health issue by WHO, there appears to be a gap in its adoption in national AMR plans. Country income levels seem to influence the progress, implementation and focus of national action plans, guided by a lack of funding and prioritization in developing countries. To better align the global response to AMR, our review suggests there is a need to update national action plans to include objectives on vaccination with more focus on specific vaccines that impact antibiotic use.

Antimicrobial Activity of Ceftaroline and Comparator Agents Against Ceftriaxone-Nonsusceptible Streptococcus pneumoniae from the United States (2008-2020)

We evaluated the activity of ceftaroline against clinical isolates of ceftriaxone-nonsusceptible Streptococcus pneumoniae from United States medical centers. Streptococcus pneumoniae isolates (n = 21,750) were consecutively collected from 201 medical centers in 2008-2020 and tested for susceptibility by broth microdilution method. Among these isolates, 1,419 (6.5%) were ceftriaxone-nonsusceptible (ceftriaxone minimum inhibitory concentration [MIC], ≥2 mg/L). Other resistant subgroups analyzed included multidrug-resistant (MDR; nonsusceptibility to ≥3 classes of agents; n = 4,454) and extensively drug-resistant (XDR; nonsusceptibility to ≥5 classes; n = 1,708) isolates. Ceftriaxone susceptibility increased from 89.0% (2008-2011) to 98.1% (2018-2020). Ceftaroline was active against 99.9% of ceftriaxone-nonsusceptible isolates (MIC_50/90, 0.25/0.25 mg/L) and retained potent activity against MDR (n = 4,454; MIC_50/90, 0.12/0.25 mg/L; >99.9% susceptible) and XDR (n = 1,708; MIC_50/90, 0.25/0.25 mg/L; 100.0% susceptible) isolates. Only one isolate had a ceftaroline MIC ≥0.5 mg/L. In summary, ceftaroline demonstrated potent and consistent activity over time (2008-2020) against a large collection of S. pneumoniae from U.S. medical centers, including ceftriaxone-nonsusceptible, MDR, and XDR isolates.

Effectiveness of Influenza Vaccination in Reducing Subsequent Antibiotic Prescribing in Young Children Attending Australian General Practices-A Case-Control Study

BACKGROUND

Vaccination against influenza may reduce antibiotic use, but data are limited and imprecise.

METHODS

We conducted a case-control study using deidentified data from a large national primary care database to evaluate antibiotic prescribing changes following influenza vaccination in children 1-4 years old attending primary care in the Australian 2018 and 2019 influenza seasons. Cases were prescribed β-lactam or macrolide antibiotics during the influenza season and controls were not. Influenza vaccination was documented in the medical records. Adjusted odds ratios for antibiotic prescribing according to influenza vaccination status were estimated using generalized estimating equations, controlling for age, asthma diagnosis, other vaccinations, practice visit frequency, and attendance week.

RESULTS

In 2018, 11 282 cases and 32 020 controls were eligible, and in 2019, 12 705 cases and 36 858 controls. Antibiotic prescriptions were less likely in vaccinated participants in 2018 (aOR, 0.65; 95% CI, 0.62-0.69) and 2019 (aOR, 0.78; 95% CI, 0.73-0.82) and did not vary by age, the number of GP visits, or prior prescribing of antibiotics. In the subgroup of children vaccinated in the preceding season, influenza vaccination was not associated with a reduction in antibiotic use (2018-aOR, 1.12; 95% CI, 0.90-1.39; 2019-aOR, 1.30; 95% CI, 1.16-1.46). From our estimates, potentially 100 000 antibiotic prescriptions could be avoided annually in Australia if all children in this age range were vaccinated.

CONCLUSIONS

Influenza vaccination may substantially reduce antibiotic prescribing among young children. This effect should be considered in the overall assessment of the costs and benefits of childhood influenza vaccination programs.

Antibiotic use attributable to specific aetiologies of diarrhoea in children under 2 years of age in low-resource settings: a secondary analysis of the MAL-ED birth cohort

OBJECTIVE

To quantify the frequency of antibiotic treatments attributable to specific enteric pathogens due to the treatment of diarrhoea among children in the first 2 years of life in low-resource settings.

DESIGN

Secondary analysis of a longitudinal birth cohort study, Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED).

SETTING

This study was conducted at eight sites in Bangladesh, Brazil, India, Nepal, Peru, Pakistan, South Africa and Tanzania.

PARTICIPANTS

We analysed 9392 reported diarrhoea episodes, including 6677 with molecular diagnostic test results, as well as 31 408 non-diarrhoeal stools from 1715 children aged 0-2 years with 2 years of complete follow-up data.

PRIMARY AND SECONDARY OUTCOME MEASURES

We estimated incidence rates and the proportions of antibiotic use for diarrhoea and for all indications attributable to the top 10 aetiologies of diarrhoea. We estimated associations between specific aetiologies and antibiotic treatment, and assessed whether clinical characteristics of the diarrhoea episodes mediated these relationships.

RESULTS

Shigella and rotavirus were the leading causes of antibiotic treatment, responsible for 11.7% and 8.6% of diarrhoea treatments and 14.8 and 10.9 courses per 100 child-years, respectively. Shigella and rotavirus-attributable diarrhoea episodes were 46% (RR: 1.46; 95% CI: 1.33 to 1.60), and 19% (RR: 1.19; 95% CI: 1.09 to 1.31) more likely to be treated with antibiotics, respectively, compared with other aetiologies. Considering antibiotic uses for all indications, these two pathogens accounted for 5.6% of all antibiotic courses, 19.3% of all fluoroquinolone courses and 9.5% of all macrolide courses. Among indicated treatments for dysentery, Shigella and Campylobacter jenjui/Campylobacter coli were responsible for 27.5% and 8.5% of treated episodes, respectively.

CONCLUSIONS

The evidence that Shigella and rotavirus were disproportionately responsible for antibiotic use due to their high burden and severity further strengthens the value of interventions targeted to these pathogens. Interventions against Campylobacter could further prevent a large burden of indicated antibiotic treatment for dysentery, which could not be averted by antibiotic stewardship interventions.

Progress Report: Antimicrobial Drug Discovery in the Resistance Era

Antibiotic resistance continues to be a most serious threat to public health. This situation demands that the scientific community increase their efforts for the discovery of alternative strategies to circumvent the problems associated with conventional small molecule therapeutics. The Global Antimicrobial Resistance and Use Surveillance System (GLASS) Report (published in June 2021) discloses the rapidly increasing number of bacterial infections that are mainly caused by antimicrobial-resistant bacteria. These concerns have initiated various government agencies and other organizations to educate the public regarding the appropriate use of antibiotics. This review discusses a brief highlight on the timeline of antimicrobial drug discovery with a special emphasis on the historical development of antimicrobial resistance. In addition, new antimicrobial targets and approaches, recent developments in drug screening, design, and delivery were covered. This review also discusses the emergence and roles of various antibiotic adjuvants and combination therapies while shedding light on current challenges and future perspectives. Overall, the emergence of resistant microbial strains has challenged drug discovery but their efforts to develop alternative technologies such as nanomaterials seem to be promising for the future.

Measuring the Link Between Vaccines and Antimicrobial Resistance in Low Resource Settings – Limitations and Opportunities in Direct and Indirect Assessments and Implications for Impact Studies

The importance of vaccines in combatting antimicrobial resistance (AMR) is commonly accepted. Although scientific reasoning supports the putative connection between vaccines and reduction of AMR, reliably measuring the magnitude and effect of vaccines on antimicrobial resistance is inherently challenging, especially in low resource settings. We review the intrinsic challenges in estimating the effect of vaccines on AMR and discuss the limitations and opportunities in current methods from the host, pathogen, and environment perspectives. We highlight advantages and pitfalls in different epidemiological study designs with a specific focus on impact studies in low resource settings and suggest how these perspectives could be considered in future research.

Factors Associated with Antimicrobial Stewardship Practices on California Dairies: One Year Post Senate Bill 27

BACKGROUND

The current study is aimed at identifying the factors associated with antimicrobial drug (AMD) use and stewardship practices on conventional California (CA) dairies a year after CA Senate Bill 27.

METHODS

Responses from 113 out of 1282 dairies mailed a questionnaire in 2019 were analyzed to estimate the associations between management practices and six outcomes including producer familiarity with medically important antimicrobial drugs (MIADs), restricted use of MIADs previously available over the counter (OTC), use of alternatives to AMD, changes in on-farm management practices, changes in AMD costs, and animal health status in dairies.

RESULTS

Producers who reported having a veterinarian-client-patient relationship (VCPR) and tracking AMD withdrawal intervals had greater odds of being familiar with the MIADs. Producers who began or increased the use of preventive alternatives to AMD in 2019 had higher odds (OR = 3.23, p = 0.04) of decreased use of MIADs previously available OTC compared to those who did not. Changes in management practices to prevent disease outbreak and the use of diagnostics to guide treatment were associated with producer-reported improved animal health. In addition, our study identified record keeping (associated with familiarity with MIADs), use of alternatives to AMD (associated with management changes to prevent diseases and decreased AMD costs), and use of diagnostics in treatment decisions (associated with reported better animal health) as factors associated with AMD stewardship.

CONCLUSIONS

Our survey findings can be incorporated in outreach education materials to promote antimicrobial stewardship practices in dairies.

Systematic review of the efficacy, effectiveness and impact of high-valency pneumococcal conjugate vaccines on otitis media

Otitis media (OM) is a common disease of childhood and available pneumococcal conjugate vaccines (PCVs), with different compositions, could have different impact on OM reduction. This systematic literature review evaluated available data describing the efficacy, effectiveness, and impact of 10-valent pneumococcal Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) and 13-valent PCV (PCV13) on OM outcomes. Statistically significant reductions in all-cause and complicated OM, tympanostomy tube placement and OM-related hospitalizations were consistently observed after the introduction of PHiD-CV and PCV13. Impact studies with data in children <2 years of age using PCV13 report 47–51% and PHiD-CV 34–43% reduction of all-cause OM (primary care, outpatient, ambulatory, emergency department visits) compared to periods before PCV introduction. When the impact of both vaccines is assessed in comparable settings, some studies suggest PHiD-CV may offer better protection against some OM outcomes. Well-designed, head-to-head comparisons are needed to better understand the differences and guide vaccination policies.

What is the context?

Pneumococcal vaccines are highly effective in preventing pneumonia and meningitis in children. The two main pneumococcal vaccines are PHiD-CV (Synflorix, GSK) and PCV13 (Prevenar 13, Pfizer). Both vaccines have been shown to provide protection against otitis media despite differing in their composition.

However, it is currently unknown if both vaccines confer similar level of protection against otitis media.

What is new?

We conducted a literature review to evaluate the effects of PHiD-CV and PCV13 on otitis media.

From 33 articles, we found that:

‡Both vaccines were effective in reducing doctor visits for otitis media as well as the number of severe cases and cases requiring hospitalization.

‡Four studies suggested a higher level of protection provided by PHiD-CV compared to PCV13, although more data is needed to confirm this finding.

What is the impact?

Available information shows that PHiD-CV and PCV13 are effective in preventing a proportion of otitis media during childhood.

Given the remaining substantial burden associated with the disease and the related significant usage of antibiotics, the development of improved vaccines with higher impact on otitis media would be welcome.

Trends, Variation, and Factors Influencing Antibiotic Prescribing: A Longitudinal Study in Primary Care Using a Multilevel Modelling Approach

Antimicrobial resistance has become one of the greatest threats to global health. Over 80% of antibiotics are prescribed in primary care, with many prescriptions considered to be issued inappropriately. The aim of this study was to examine the association between prescribing rates and demographic, practice, geographic, and socioeconomic characteristics using a multilevel modelling approach. Antibiotic prescribing data by 320 GP surgeries in Northern Ireland were obtained from Business Services Organisation for the years 2014–2020. A linear mixed-effects model was used to identify factors influencing antibiotic prescribing rates. Overall, the number of antibacterial prescriptions decreased by 26.2%, from 1,564,707 items in 2014 to 1,155,323 items in 2020. Lower levels of antibiotic prescribing were associated with urban practices (p < 0.001) and practices in less deprived areas (p = 0.005). The overall decrease in antibacterial drug prescriptions over time was larger in less deprived areas (p = 0.03). Higher prescribing rates were linked to GP practices located in areas with a higher percentage of the population aged ≥65 (p < 0.001) and <15 years (p < 0.001). There were also significant regional differences in antibiotic prescribing. We advocate that any future antibiotic prescribing targets should account for local factors.

Subtractive genomic approach toward introduction of novel immunogenic targets against Clostridioides difficile: Thinking out of the box

Clostridioides difficile is one of the major causatives of nosocomial infections worldwide. Antibiotic-associated diarrhea, pseudomembranous colitis, and toxic megacolon are the most common forms of C. difficile infection (CDI). Considering the high antibiotic resistance of C. difficile isolates and the low efficacy of immunization with toxin-related vaccines, we suggested that surface-exposed and secreted proteins could be considered as potential immunogenic targets against CDI. Various immuninformatics databases were used to predict antigenicity, allergenicity, B-cell epitopes, MHC-II binding sites, conserved domains, prevalence and conservation of proteins among the most common sequence types, molecular docking, and immunosimulation of immunogenic targets. Finally, 16 proteins belonging to three functional groups were identified, including proteins involved in the cell wall and peptidoglycan layer (nine proteins), flagellar assembly (five proteins), spore germination (one protein), and a protein with unknown function. Molecular docking results showed that among all the mentioned proteins, WP_009892971.1 (Acd) and WP_009890599.1 (a C40 family peptidase) had the strongest interactions with human Toll-like receptor 2 (TLR-2) and TLR-4. This study proposes a combination of C. difficile toxoid (Tcd) and surface-exposed proteins such as Acd as a promising vaccine formulation for protection against circulating clinical strains of C. difficile.

Influenza Vaccines: Successes and Continuing Challenges

Influenza vaccines have been available for over 80 years. They have contributed to significant reductions in influenza morbidity and mortality. However, there have been limitations in their effectiveness, in part due to the continuous antigenic evolution of seasonal influenza viruses, but also due to the predominant use of embryonated chicken eggs for their production. The latter furthermore limits their worldwide production timelines and scale. Therefore today, alternative approaches for their design and production are increasingly pursued, with already licensed quadrivalent seasonal influenza vaccines produced in cell cultures, including based on a baculovirus expression system. Next-generation influenza vaccines aim at inducing broader and longer-lasting immune responses to overcome seasonal influenza virus antigenic drift and to timely address the emergence of a new pandemic influenza virus. Tailored approaches target mechanisms to improve vaccine-induced immune responses in individuals with a weakened immune system, in particular older adults.

Survey among Italian experts on existing vaccines' role in limiting antibiotic resistance

Antimicrobial resistance (AMR) is a major public health problem threatening to reverse the progress made against infectious diseases. The rapid increase of AMR exposes Italian hospitals at increased risk of untreatable infections. Vaccinations can potentially limit AMR by reducing the number of infected cases in need of antibiotics. We conducted a survey among Italian vaccine experts to record their opinion regarding the role of vaccinations against antibiotic resistance (ABR). Among 80 invited experts, 51 answered all questions. Most respondents were experts in hygiene and preventive medicine (56.9%) and aged >50 years (72.6%). ABR was a priority concern in the daily professional activity of 82.4% of respondents. Overall, 47.1% of respondents believed that all vaccinations included in the vaccination calendar played a role against ABR: 92.2% for pertussis vaccination followed by 88.2%, 74.5%, and 70.6% for meningococcus, measles, and varicella vaccinations, respectively. Almost all respondents agreed that the role of vaccinations against ABR should be clearly expressed in the national vaccination guidelines (96.1%) and Scientific Societies should take an explicit position on the issue (92.2%). These results show that Italian experts have recognized the vaccinations’ potential role in limiting ABR and guidelines from the appropriate scientific and governmental authorities are needed.

Trend of antibiotic consumption and its association with influenza-like illnesses in France between 2004 and 2018

BACKGROUND

Antibiotic consumption has been reported to be driven by the treatment of respiratory tract infections. Our objectives were to describe the trend of antibiotic consumption in France compared with that of other European countries; to describe the evolution of each antibiotic class in France; and to explore the relationship between antibiotic consumption and incidence of influenza-like illnesses.

METHODS

In this observational study, antibiotic consumption was reported as defined daily doses per 1000 inhabitants per day in the community and hospital sectors in descriptive and graphical formats, using data from the European Surveillance of Antimicrobial Consumption Network database. The total consumption and the consumption of different classes of antibiotics in France according to time and influenza-like illnesses were studied using multiple linear regression models.

RESULTS

The total consumption of antibiotics in France was constant over the 15 years. It was driven by the community sector (92.8%) and was higher than the consumption of other European Union countries (P-value < 0.001). The beta-lactam penicillins were the most consumed antibiotic class and the only class that increased with time. The multiple linear regression models showed a positive correlation between antibiotic consumption in the community sector and incidence of influenza-like illnesses [B = 0.170, 95% CI (0.088-0.252)]. Similar significant results were shown between other antibiotic classes used in the management of influenza-like illnesses (other beta-lactams, and macrolides, lincosamides and streptogramins) and influenza-like illnesses.

CONCLUSION

Our results suggest that antibiotics used in the management of respiratory tract infections might be involved in the irrational use of antibiotics.

Antimicrobial resistance in paediatric Streptococcus pneumoniae isolates amid global implementation of pneumococcal conjugate vaccines: a systematic review and meta-regression analysis

BACKGROUND

Pneumococcal diseases are a leading cause of morbidity and mortality among children globally, and the burden of these diseases might be worsened by antimicrobial resistance. To understand the effect of pneumococcal conjugate vaccine (PCV) deployment on antimicrobial resistance in pneumococci, we assessed the susceptibility of paediatric pneumococcal isolates to various antimicrobial drugs before and after PCV implementation.

METHODS

We did a systematic review of studies reporting antimicrobial susceptibility profiles of paediatric pneumococcal isolates between 2000 and 2020 using PubMed and the Antimicrobial Testing Leadership and Surveillance database (ATLAS; Pfizer). Population-based studies of invasive pneumococcal disease or nasopharyngeal colonisation were eligible for inclusion. As primary outcome measures, we extracted the proportions of isolates that were non-susceptible or resistant to penicillin, macrolides, sulfamethoxazole-trimethoprim, third-generation cephalosporins, and tetracycline from each study. Where available, we also extracted data on pneumococcal serotypes. We estimated changes in the proportion of isolates with reduced susceptibility or resistance to each antibiotic class using random-effects meta-regression models, adjusting for study-level and region-level heterogeneity, as well as secular trends, invasive or colonising isolate source, and countries' per-capita gross domestic product.

FINDINGS

From 4910 studies screened for inclusion, we extracted data from 559 studies on 312 783 paediatric isolates. Susceptibility of isolates varied substantially across regions both before and after implementation of any PCV product. On average across all regions, we estimated significant absolute reductions in the proportions of pneumococci showing non-susceptibility to penicillin (11·5%, 95% CI 8·6-14·4), sulfamethoxazole-trimethoprim (9·7%, 4·3-15·2), and third-generation cephalosporins (7·5%, 3·1-11·9), over the 10 years after implementation of any PCV product, and absolute reductions in the proportions of pneumococci resistant to penicillin (7·3%, 5·3-9·4), sulfamethoxazole-trimethoprim (16·0%, 11·0-21·2), third-generation cephalosporins (4·5%, 0·3-8·7), macrolides (3·6%, 0·7-6·6) and tetracycline (2·0%, 0·3-3·7). We did not find evidence of changes in the proportion of isolates non-susceptible to macrolides or tetracycline after PCV implementation. Observed changes in penicillin non-susceptibility were driven, in part, by replacement of vaccine-targeted serotypes with non-vaccine serotypes that were less likely to be non-susceptible.

INTERPRETATION

Implementation of PCVs has reduced the proportion of circulating pneumococci resistant to first-line antibiotic treatments for pneumonia. This effect merits consideration in assessments of vaccine impact and investments in coverage improvements.

FUNDING

Bill & Melinda Gates Foundation.

Leveraging Vaccines to Reduce Antibiotic Use and Prevent Antimicrobial Resistance: A World Health Organization Action Framework

This Action Framework identifies priority actions to prevent antimicrobial-resistant (AMR) through expanding the use of licensed vaccines, developing new vaccines that contribute to the prevention and control of AMR, and expanding knowledge about the impact of vaccines on AMR.

Modeling the effect of vaccination on selection for antibiotic resistance in Streptococcus pneumonia e

Vaccines against bacterial pathogens can protect recipients from becoming infected with potentially antibiotic-resistant pathogens. However, by altering the selective balance between antibiotic-sensitive and antibiotic-resistant bacterial strains, vaccines may also suppress-or spread-antibiotic resistance among unvaccinated individuals. Predicting the outcome of vaccination requires knowing what drives selection for drug-resistant bacterial pathogens and what maintains the circulation of both antibiotic-sensitive and antibiotic-resistant strains of bacteria. To address this question, we used mathematical modeling and data from 2007 on penicillin consumption and penicillin nonsusceptibility in Streptococcus pneumoniae (pneumococcus) invasive isolates from 27 European countries. We show that the frequency of penicillin resistance in S. pneumoniae can be explained by between-host diversity in antibiotic use, heritable diversity in pneumococcal carriage duration, or frequency-dependent selection brought about by within-host competition between antibiotic-resistant and antibiotic-sensitive S. pneumoniae strains. We used our calibrated models to predict the impact of non-serotype-specific pneumococcal vaccination upon the prevalence of S. pneumoniae carriage, incidence of disease, and frequency of S. pneumoniae antibiotic resistance. We found that the relative strength and directionality of competition between drug-resistant and drug-sensitive pneumococcal strains was the most important determinant of whether vaccination would promote, inhibit, or have little effect upon the evolution of antibiotic resistance. Last, we show that country-specific differences in pathogen transmission substantially altered the predicted impact of vaccination, highlighting that policies for managing antibiotic resistance with vaccines must be tailored to a specific pathogen and setting.

Fostering healthy aging: The interdependency of infections, immunity and frailty

Untangling the interdependency of infections, immunity and frailty may help to clarify their roles in the maintenance of health in aging individuals, and the recent COVID-19 pandemic has further highlighted such priority. In this scoping review we aimed to systematically collect the evidence on 1) the impact of common infections such as influenza, pneumonia and varicella zoster on frailty development, and 2) the role played by frailty in the response to immunization of older adults. Findings are discussed under a unifying framework to identify knowledge gaps and outline their clinical and public health implications to foster a healthier aging. Twenty-nine studies (113,863 participants) selected to answer the first question provided a moderately strong evidence of an association between infections and physical as well as cognitive decline - two essential dimensions of frailty. Thirteen studies (34,520 participants) investigating the second aim, showed that frailty was associated with an impaired immune response in older ages, likely due to immunosenescence. However, the paucity of studies, the absence of tools to predict vaccine efficacy, and the lack of studies investigating the efficacy of newer vaccines in presence of frailty, strongly limit the formulation of more personalized immunization strategies for older adults. The current evidence suggests that infections and frailty repeatedly cross each other pathophysiological paths and accelerate the aging process in a vicious circle. Such evidence opens to several considerations. First, the prevention of both conditions pass through a life course approach, which includes several individual and societal aspects. Second, the maintenance of a well-functioning immune system may be accomplished by preventing frailty, and vice versa. Third, increasing the adherence to immunization may delay the onset of frailty and maintain the immune system homeostasis, beyond preventing infections.