Impact of the COVID-19 related border restrictions on influenza and other common respiratory viral infections in New Zealand.

BACKGROUND: New Zealand's (NZ) complete absence of community transmission of influenza and respiratory syncytial virus (RSV) after May 2020, likely due to COVID-19 elimination measures, provided a rare opportunity to assess the impact of border restrictions on common respiratory viral infections over the ensuing 2 years. METHODS: We collected the data from multiple surveillance systems, including hospital-based severe acute respiratory infection surveillance, SHIVERS-II, -III and -IV community cohorts for acute respiratory infection (ARI) surveillance, HealthStat sentinel general practice (GP) based influenza-like illness surveillance and SHIVERS-V sentinel GP-based ARI surveillance, SHIVERS-V traveller ARI surveillance and laboratory-based surveillance. We described the data on influenza, RSV and other respiratory viral infections in NZ before, during and after various stages of the COVID related border restrictions. RESULTS: We observed that border closure to most people, and mandatory government-managed isolation and quarantine on arrival for those allowed to enter, appeared to be effective in keeping influenza and RSV infections out of the NZ community. Border restrictions did not affect community transmission of other respiratory viruses such as rhinovirus and parainfluenza virus type-1. Partial border relaxations through quarantine-free travel with Australia and other countries were quickly followed by importation of RSV in 2021 and influenza in 2022. CONCLUSION: Our findings inform future pandemic preparedness and strategies to model and manage the impact of influenza and other respiratory viral threats.

Effect of directive laboratory comments on prescribing response to positive throat swab cultures.

BACKGROUND: In patients without ethnicity risk factors for acute rheumatic fever (ARF), our local guidelines recommend limiting antibiotic use following a positive throat swab culture (TSC). If symptoms are severe, a 5-7 day course is recommended. Despite this, most local patients with a positive TSC for group A Streptococcus (GAS) or Streptococcus dysgalactiae subsp. equisimilis (SDSE) were being prescribed 10 days of antibiotics. In response, we added comments to positive TSC reports recommending shorter treatment durations in those without ARF risk factors. No other antimicrobial stewardship initiatives were implemented. OBJECTIVES: To assess the effect of these comments on antibiotic course duration after positive TSC. METHODS: All community TSC results from 1 October 2021 to 31 March 2023 (1 year pre- to 6 months post-change) were matched to antibiotic dispensing data. Patients who had been empirically dispensed an antibiotic prior to the culture report were excluded. The outcome of interest was the antibiotic duration dispensed in the 5 day period after the TSC report. RESULTS: Following introduction of the comments, median course duration reduced from 10 (IQR 5-10) to 7 days (IQR 0-10; P < 0.01) and from 7 (IQR 0-10) to 0 days (IQR 0-5; P < 0.01) following GAS- and SDSE-positive TSC, respectively, in those without ARF risk factors. The percentage of people receiving 10 days of antibiotics decreased from 63.0% to 37.0% (P < 0.01) and 41.2% to 14.6% (P < 0.01) for GAS and SDSE, respectively. CONCLUSIONS: The introduction of comments providing direct prescribing advice to requestors appears to have been highly effective at improving guideline-compliant prescribing following positive TSC report.

Post-report antibiotic initiation following community non-sterile-site microbiology results: an opportunity for labs to lead stewardship?

OBJECTIVES: Positive culture results from non-sterile sites (NSSs) are poorly predictive of clinical infection. Despite this, these results are often interpreted as an indication for antibiotics, even in patients with limited signs of infection. We sought to quantify the influence of NSS culture results on post-report antibiotic initiation (PRAI) in patients who had not been started on antibiotics pre-report. METHODS: All community wound/skin swab and sputum cultures were matched to antibiotic dispensing records from February 2017 to July 2022. Prescribing behaviour was assessed pre- and post-report. Sampling without treatment pre-report was termed 'test-and-wait' (TaW). Following TaW, PRAI was identified if antibiotics were started within 5 days post-report. RESULTS: There were 65 480 wound/skin swabs and 8126 sputum samples, with TaW occurring in 21 740 (35.1%) and 4185 (54.4%), respectively. Following a TaW approach PRAI occurred in 43.3% when an organism was reported, versus 10.8% (P < 0.01) for a 'no growth' report for wound/skin swabs. For the same comparison with sputum, PRAI occurred in 47.9% versus 10.8% (P < 0.01). On multivariate analysis reporting an organism remained strongly associated with PRAI. CONCLUSIONS: Reporting an organism in those not already on antibiotics was strongly associated with PRAI. We hypothesize that for many patients TaW suggests limited evidence of infection (i.e. insufficient to justify antibiotic treatment at time of sampling), meaning positive NSS results may be driving a considerable volume of potentially unnecessary antibiotic use. Further study on this topic is required, but strategies to reduce PRAI may offer laboratories an opportunity to meaningfully impact antimicrobial stewardship efforts.