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Weekly Digest: Generic market entry has limited effects on antibiotic use in the US; Mass and systematic antibiotic administration may increase antibiotic resistance in LMIC; COVID-19 app may have reduced COVID-19 cases; Will SARS-CoV-2 become just another seasonal coronavirus?

Generic market entry has limited and inconsistent effects on antibiotic use in the United States. In a study led by CDDEP and Oslo University researchers,  changes in monthly antibiotic prescriptions were assessed for 13 antibiotics with at least one generic entry in the US market between 2000 and 2012.  Using interrupted time series analysis and data from the IQVIA Xponent database, researchers showed that prescription levels increased (5 to 406%) for five antibiotics (aztreonam, cefpodoxime, ciprofloxacin, levofloxacin, ofloxacin), and decreased for one antibiotic (cefdinir), immediately after and in the two years following generic entry.  Acknowledging the multitude of factors that could affect antibiotic use, such as generic entry of similar drugs, the introduction of vaccines, and changes in treatment recommendations, the researchers concluded that generic entry has limited and inconsistent effects on antibiotic use in the United States. [Nature Communications]

Mass and systematic antibiotic administration may increase antibiotic resistance in low- and middle-income countries. Efforts to control infectious diseases spread among communities in low- and middle-income countries (LMIC) by mass and systematic antibiotic administration (MDA/SDA) may come with the price of increasing antibiotic resistance. As MDA/SDA interventions target vulnerable groups of the population overrepresented in LMIC, some populations may be targeted by more than one intervention. A systematic review from researchers at the Pasteur Institute and Paris-Saclay University reviewed 63 articles, 40% of which evaluated antibiotic resistance, and found that MDA/SDA interventions lead to greater AR prevalence, especially those involving co-trimoxazole and azithromycin. The findings from this review underscore the great need for guidelines for AR evaluation in the context of MDA/SDA interventions. [International Journal of Antimicrobial Agents]

Evidence suggests United Kingdom’s NHS COVID-19 app may have reduced COVID-19 cases. To reduce COVID-19 transmission, the National Health Service launched a smartphone app for England and Wales to notify and instruct users to quarantine if they had contact with another user later confirmed to have COVID-19 exposure. Among 21 million users, 560,000 tested positive for COVID-19 over the study period. Analyzing data from September 24, 2020, to December 31, 2020, researchers found an association between increased use of the app and reduced COVID-19 cases. Modeling and statistical analyses of app use estimated that for every percentage point increase in app users, cases were reduced by 0.8% and 2.3%, with most of the cases averted in November and December 2020. [Nature]

Disparities in COVID-19 vaccination in the US. The US Centers for Disease Control and Prevention analyzed rural versus urban disparities in COVID-19 vaccination coverage for adults who received the first dose of the Pfizer/BioNTech or Moderna or the single dose of the Johnson & Johnson vaccine between December 14, 2020, and April 10, 2021. The analysis covered 49 states (Hawaii was not included) and Washington, DC. Overall, as expected, coverage was lower in rural than urban counties (38.9% versus 45.7%). For women in rural counties, coverage was 41.7% versus 48.4% in urban areas, while coverage for men in rural areas was 35.3% compared to 41.9% in urban counties. Vaccination coverage by race and ethnicity was not estimated due to data missingness. [MMWR]

Allocating to older age groups and proportional to country population the most effective and equitable COVID-19 vaccine strategy. Researchers at Imperial College London used an age-structured deterministic SEIR compartmental model to identify vaccine allocation strategies within- and between countries to avert the most deaths and life years lost according to different supply scenarios. For limited doses within a country ( doses for <20% of the population), targeting the elderly is the optimal strategy for all income settings. With a larger supply and with other prevention measures maintained, targeting key transmitters is the optimal strategy. With increasing supplies, vaccines that reduce transmission potential have a more significant impact than those that prevent severe disease. Results suggest that given a 2 billion global dose supply, allocating to countries proportional to population size and age groups maximizes deaths averted and aligns with ethical principles in vaccine distribution. [Vaccine]

Antimicrobial stewardship programs impact antimicrobial use in US Hospitals. Researchers in the United States conducted a hospital prevalence survey of healthcare-associated infections and antibiotic use in 2015 to assess any changes since the previous survey in 2011. Of the 12,299 randomly selected patients, an estimated 49.5% received antimicrobials between May and September 2015. Overall antimicrobial use prevalence did not significantly change between 2011 and 2015 for the 148 hospitals included in both surveys. However, there was a decrease in the percentage of neonatal critical care patients on antimicrobials, a decrease in the use of fluoroquinolone, and an increase in 3rd- or 4th-generation cephalosporin and carbapenem, suggesting impacts of antimicrobial stewardship programs in select patient groups or antimicrobials [Clinical Infectious Diseases].

Organic meat has fewer multi-drug resistant bacteria. Researchers at Johns Hopkins University analyzed antimicrobial susceptibility testing (AST) surveillance data for samples of common consumer meat products tested between 2012 and 2017 from 19 states across the US and found that 3.6% (1,422 of 39,348 samples) had at least one multi-drug resistant bacterium (MDRB). The National Antimicrobial Resistance Surveillance Monitoring System collected AST data on four bacteria – Salmonella, Campylobacter, Escherichia coli, and Enterococcus – and included AST results from chicken breast, ground turkey, ground beef, and pork chops. Organically produced and processed meat was significantly less likely to have an MDRB than meat processed conventionally. [EHP]

Antibiotic prescribing was higher in rural areas in Kentucky, US, between 2012 and 2017. There is substantial geographic variation in antibiotic use across the United States, with particularly high rates of antibiotic use in southern states. In 2017, Kentucky had the second-highest rate (1,281 prescriptions per 1,000 children per year) of outpatient antibiotic prescriptions for children. Using Medicaid prescription claims data from 2012 to 2017, researchers found higher antibiotic prescription rates in rural areas, particularly among children who were female, less than two years old, and white. General practitioners and nurse practitioners prescribed most antibiotic prescriptions for children. While the study could not determine the extent of inappropriate prescribing, the large volume of antibiotic prescriptions in rural areas highlights the need for outpatient antimicrobial stewardship initiatives in these areas. [The Journal of Rural Health]

Will SARS-CoV-2 become just another seasonal coronavirus?  In the context of the COVID-19 pandemic and the road to achieving avirulence, researchers at the University of Utah developed a mathematical model where infections can be “high-shedding” or “low-shedding,” to test three potential factors that would reduce disease severity: 1) persistence of mild cases with less virus shedding 2) lower susceptibility to severe infection in children which in turn would be considered sources of mild, low shedding infections, and 3) partial immunity in the population at large because of the current level of exposure. They predicted that these factors together could act to reduce the cases of severe infections significantly and that the initial outbreak could progress to an endemic state characterized by mild infections like the seasonal coronaviruses. [Viruses]

Online communication training of pediatric clinicians may increase rates of HPV vaccination. Researchers in the US conducted a cluster-randomized clinical trial including 48 pediatric practices across 19 states to assess the effect of communication training for clinicians on missed opportunities for HPV vaccination rates, with the primary outcomes being missed opportunities for HPV vaccination overall, HPV vaccine initiation, and subsequent doses at well-child care (WCC) and acute or chronic visits. The study included 29 206 and 33 914 adolescents who visited intervention and control practices, respectively. The findings indicated that online effective communication training of clinicians reduced missed opportunities for HPV vaccination, especially by improving receipt of the first HPV vaccine dose. [JAMA Pediatrics]

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