Higher COVID-19 transmission tied to crowded households
COVID-19 transmission among households was three times more likely if the household had a high living density, according to a study yesterday in Clinical Infectious Diseases. Higher living density is defined as having more than three household members but fewer than six rooms.
The researchers looked at 100 COVID-19 index patients, all adults, and household contacts of all ages from April to October 2020 in North Carolina. Participants were enrolled in the study a median of 6 days after the index patient’s symptom onset or diagnosis. On days 7, 14, and 21 from symptom onset, the household submitted nasal swabs, and on day 28, they underwent a seroconversion test, although the researchers note that 38% of households did not have complete participation.
Overall secondary attack rate was 32% (95% confidence interval [CI], 22% to 44%). However, it was higher in households with high living density (51% vs 19%), indicating that those members were 3.3 times more likely to get COVID-19 (95% CI, 1.02 to 10.9). The researchers say this could be a factor in the disproportionate effect of COVID-19 among minorities. For instance, in their cohort, 42% of non-White index patients lived in a higher living density situation vs 12% of White index patients.
“Households with non-White index cases were more likely to experience incident transmission in the household, despite there being no difference in index case viral loads by race/ethnicity,” the researchers write. “Household crowding in the context of high-inoculum infections may amplify the spread of COVID-19, potentially contributing to disproportionate impact on communities of color.”
The researchers were unable to assess associations with age, mask-wearing, and symptoms during transmission, nor did they analyze index case viral loads.
Aug 12 Clin Infect Dis study
Significant decline noted in outpatient antibiotic use in British Columbia
Outpatient antibiotic use in British Columbia has declined by more than 23% over the last two decades, driven by significant decreases in pediatric use, Canadian researchers reported yesterday in JAC-Antimicrobial Resistance.
The retrospective cohort study looked at all antibiotic prescriptions extracted from BC PharmaNet, a centralized database linked to all pharmacies in the province, from 2000 to 2018. The study period included 5 years prior to the 2005 launch of the Community Antimicrobial Stewardship (CAS) program, a province-wide effort to educate the public about judicious antibiotic use and encourage stewardship. Researchers examined overall oral antibiotic use, antibiotic use by class and age, and trends over time to evaluate the impact of the program.
More than 51 million outpatient antibiotics were dispensed over the study period, at an overall average rate of 609 prescriptions per 1,000 population. Outpatient prescribing declined by 23.1%, from 652 to 503 prescriptions per 1,000 population. Declining use was observed for penicillins (–27%), macrolides (–43%), sulphonamides and trimethoprim (–58%), quinolones (–22%), and other beta-lactams (–12%). The sharpest declines were seen among pediatric patients, with a negative association between increasing age and decreasing magnitude of antibiotic reduction. Upper respiratory tract infections were the most prescribed indication in 2018.
The analysis found that antibiotic prescribing for common infections declined by 4% (rate ratio [RR], 0.96; 95% confidence interval [CI], 0.96 to 0.97) from 2005 to 2013 (era 1) compared with the pre-stewardship period. From 2014 to 2018 (era 2), when a focus on judicious prescribing for urinary tract infections was added to the CAS, prescribing declined by 24% (RR, 0.76; 95% CI, 0.76 to 0.76) compared with the pre-stewardship period. Antibiotic prescribing for children 0 to 2 years of age declined by 54% (RR, 0.46; 95% CI, 0.46 to 0.46) in era 2, while prescribing in patients over 80 increased by 12% (RR, 1.12; 95% CI, 1.11 to 1.12).
“Although this study cannot attribute causation, a substantial decline in antibiotic use was observed in our 19 year study period, with temporal correlations between targeted stewardship eras and related optimizations in antibiotic use,” the study authors wrote. “Despite this progress, prescribing in our eldest cohorts is increasing, and optimizing prescribing to our most vulnerable population remains a provincial target.”
Aug 12 JAC-Antimicrob Resist study
Study shows zanamivir might be most effective antiviral for influenza
For healthy adults and children, zanamivir may be the most effective antiviral used to shorten the duration of influenza symptoms, according to a new study in JAMA Network Open.
The study reviewed 26 trials that looked at antiviral drugs at high or low doses. The trials included 11,897 participants with a median age of 32.5, and 52.9% of them were men. Primary outcomes were the time to alleviation of influenza symptoms (TTAS), complications of influenza, and adverse events (total adverse events, nausea, and vomiting).
The studies measured how well flu was treated with neuraminidase inhibitors (oseltamivir, peramivir, zanamivir, or laninamivir) or an endonuclease inhibitor (baloxavir), compared with a placebo.
High-quality evidence showed zanamivir, commonly known by the brand name Relenza, as associated with the shortest TTAS (hazard ratio, 0.67; 95% CI, 0.58-0.77), while baloxavir was associated with the lowest risk of influenza-related complications (risk ratio [RR], 0.51; 95% CI, 0.32-0.80.). But the evidence for baloxavir was of moderate quality. Baloxavir had the lowest risk of total adverse events.
“To our knowledge, this is the first study to simultaneously compare the efficacy of baloxavir and 3 neuraminidase inhibitors, the 4 drugs most commonly used for patients with influenza in current clinical practice,” the authors said. “Network meta-analysis studies such as this may have utility in informing treatment guidelines for viral conditions, like influenza, when few direct comparisons between individual therapies are available.”
Aug 13 JAMA Netw Open study
Three African nations report more vaccine-derived polio cases
Three African countries reported more polio cases this week, all involving circulating vaccine-derived poliovirus type 2, the Global Polio Eradication Initiative (GPEI) said in its latest weekly update.
Ethiopia reported 1 case, which involves a patient from Oromiya state in the central part of the country, bringing its total for the year to 7. Mali reported 2 cases, one in Mopti and the other in Sikasso, which are included in its 2020 total—now at 50.
Also, Nigeria reported 3 new cases in different states: Kebbi, Nasarawa, and Rivers. The country now has 68 cases this year.
Aug 12 GPEI weekly update