The rate of oral antibiotic prescriptions dispensed in US outpatient pharmacies fell by 13% from 2011 to 2019, with the biggest declines observed in children, researchers reported last week in the American Journal of Epidemiology.

Using the IQVIA Xponent database and US Census bureau population estimates, researchers from the Centers for Disease Control and Prevention found that a total of 2.4 billion oral antibiotic prescriptions were dispensed from 2011 to 2019, with adults aged 65 and older, women, and the South region consistently accounting for the highest prescription rates. Penicillins, macrolides, and cephalosporins were the antibiotic classes with the highest prescription rates.

The prescription rate fell from 877 prescriptions per 1,000 persons in 2011 to 765 prescriptions/1,000 persons in 2018 and 2019 (–13%). The greatest overall decreases in prescribing rates were among children younger than 20 years (–25%), followed by adults aged 20 to 64 years (–10%), and the smallest decrease was among adults aged 65 and older (–1%).

Shifting trends in antibiotic classes

Among antibiotic classes, the largest annual decrease (measured as average annual percent change [AAPC]) across all age-groups for the entire study period was for macrolides (AAPC, aged 20 years and younger, –8%; aged 2o to 64 years, –3.8%; aged 65 and older, –5.1%). 

From 2016 to 2019, the largest annual decrease occurred in fluoroquinolones across all age-groups (AAPC, aged 20 years and younger, –14.8%; aged 20 to 64 years, –12.7%;  aged 65 and older, –11.2%). Among adults, during the study period, prescribing rates increased for beta-lactams (AAPC, aged 20 to 64 years, 6.4%; aged 65 and older, 5.6%), while cephalosporin use increased among adults 65 and older (AAPC, 2.4%).

The study authors say the small decline in antibiotic prescribing among older adults highlights the need to further evaluate prescribing practices in this population.

"Monitoring antibiotic prescribing trends nationally and by patient characteristics and antibiotic class is important for tracking progress toward goals to reduce unnecessary prescribing, optimize the treatment of infections, and mitigate antimicrobial resistance," they wrote.

Results from an online survey in Denmark describe fatigue and post-exertional malaise as prominent features 2 to 18 months after COVID-19 infections for both mild and severe cases. The study appeared today JAMA Network Open. 

The study was based on responses from 50,115 individuals (median age 57), of whom 25,249 (50.4%) were test positive and 24,866 (49.6%) were test negative at the time of study enrollment. The participants completed repeated, self-reported online questionnaires that collected information on fatigue.

"The index test date for the majority of test-positive and test-negative participants took place during the Omicron-dominant period," the authors said. 

When compared to COVID test-negative participants, test-positive participants had a significant 3% increase in scores for fatigue compared with test-negative participants (score ratio [SR] 1.0; 95% confidence interval [CI], 1.03 to 1.04). The test-positive participants also had higher odds of self-reported postexertional malaise (odds ratio, 2.04; 95% CI, 1.81 to 2.30).

Hospitalization linked to more fatigue 

Participants who were hospitalized with COVID-19 had increased fatigue scores by 23% (SR, 1.23; 95% CI, 1.20 to 1.26) compared with test-negative participants. 

Of the possible predisposing factors explored, acute SARS-CoV-2 hospitalization had the greatest impact on fatigue scores

"Of the possible predisposing factors explored, acute SARS-CoV-2 hospitalization had the greatest impact on fatigue scores," the authors concluded. Contrary to other findings, the authors said their study did not show a link between preexisting psychiatric conditions and long COVID fatigue.

"We observed a greater risk of PCC [post–COVID-19 condition] fatigue symptoms among individuals who tested positive during the Alpha wave, when most were not yet vaccinated," the authors concluded. "Persons who had received no or only 1 vaccine dose before testing had higher SRs across several follow-up points, compared with persons who had received 2 or 3 doses."

The effectiveness of the long-acting monoclonal antibody nirsevimab (Beyfortus) against primary care visits for lower respiratory tract infections (LRTIs) caused by the respiratory syncytial virus (RSV) was 76% in 160 infants younger than 10 months old from November 2023 to February 2024, researchers in Murcia and Valencia, Spain, reported late last week in Pediatrics.

In September 2023, the Spanish national immunization program targeted three groups at high risk for severe RSV based on their birth date and underlying conditions: those born during the vaccination campaign (seasonal group), those younger than 6 months at the start of the campaign (catch-up group), and those aged 6 to 24 months with high-risk conditions at the campaign start.

RSV is the main cause of LRTIs in children younger than 5 years, the authors noted. 

Role of catch-up vaccination

Investigators with the MEDiterranean Infectious diseases PRIMary care (MEDIPRIM) network of primary care centers used a test-negative study design to estimate the effectiveness of nirsevimab against medically attended RSV-LRTIs among all infants born after April 1, 2023. In total, 141 babies (88%) received the drug, 29 of them at birth and 112 through the catch-up program.

This study underscores the effectiveness of nirsevimab in preventing medically attended LRTI in infants in outpatient settings and emphasizes the importance of a catch-up immunization program to reduce the disease burden in primary care.

Forty-four infants overall (27.5%) tested positive for RSV, and 116 served as controls. Three-quarters (75%) of infected infants had been vaccinated against RSV, as were 93% of controls. Seven children were hospitalized, three of whom were 3 months or older. Of those children, three tested positive for RSV and were younger than 3 months old; two of the three had been vaccinated, as was one control. 

The estimated effectiveness of the RSV vaccine was 75.8% (95% credible interval [CI], 40.4% to 92.7%) overall and 80.2% (95% CI, 44.3% to 95.4%) in infants in the catch-up group.

"This study underscores the effectiveness of nirsevimab in preventing medically attended LRTI in infants in outpatient settings and emphasizes the importance of a catch-up immunization program to reduce the disease burden in primary care," the researchers wrote.