Ocular Antibiotic Use in Young Danish Children From 2016 to 2024

1. Introduction

Ocular antibiotics are commonly prescribed to treat eye infections. Among young children, around half of acute conjunctivitis cases are bacterial, but distinguishing between viral and bacterial conjunctivitis can be challenging [1]. Most cases resolve spontaneously without treatment, although antibiotic treatment can modestly reduce symptom duration [1, 2]. Prescriptions may also be motivated by parental pressure and day care policies requiring treatment for re‐entry, raising concerns about inappropriate use and antibiotic resistance [3]. To address such issues, Choosing Wisely programmes have been launched in over 30 countries. In Denmark, Choosing Wisely was established in 2020 as a collaboration between healthcare professionals and patient organisations [4]. The Danish initiative emphasizes consensus‐based development of ‘do‐not’ recommendations and local implementation. One of Choosing Wisely Denmark's key aims is to reduce unnecessary healthcare interventions, including antibiotic overuse. In support of a forthcoming Choosing Wisely recommendation in the autumn of 2025, this study analyses trends in ocular antibiotic use in Danish children from 2016 to 2024, extending previous work [5].

2. Methods

We conducted a nationwide descriptive drug utilization study using individual‐level data on all redeemed prescriptions for ocular antibiotics in children under 6 years old, from 1 January 2016 to 31 December 2024.

2.1. Data Sources

Prescription data were obtained from the Danish National Prescription Registry, which contains individual‐level information on all prescriptions dispensed at community pharmacies in Denmark since 1995. All ocular antibiotics require a prescription. We included the Anatomical Therapeutic Chemical (ATC) groups S01AA (general antibiotics) and S01AE (fluoroquinolones). Sulfonamides (S01AB) were not marketed during the study period.

2.2. Statistical Analyses

Four different analyses were performed. First, the annual prevalence was calculated as the total number of children redeeming at least one prescription for any ocular antibiotic each year divided by the total population of children that year, reported per 1000 individuals and stratified by sex, age group (0–1 and 2–5 years) and antibiotic type (chloramphenicol [S01AA01], fusidic acid [S01AA13], tobramycin [S01AA12], ciprofloxacin [S01AE03], and others [all remaining codes under S01AA and S01AE]).

Second, annual and monthly incidence rates (IR) of antibiotic use were calculated as the number of treatment episodes per 1000 children, stratified by sex, age, residential region and municipality. Clusters of prescriptions separated by less than 14 days were considered part of the same treatment episode.

Third, the number of antibiotic treatment episodes per child in 2024 was assessed by estimating the proportion of children who received 1, 2 or 3+ treatment episodes using a 365‐day look‐back period from each child's birthday in 2024. These results were stratified by 1‐year age bins.

Fourth, we investigated the type of prescriber responsible for each prescription.

Analyses were conducted using Stata version 18 (StataCorp, College Station, TX).

The study was conducted in accordance with the Basic & Clinical Pharmacology & Toxicology policy for experimental and clinical studies [6].

3. Results

From 2016 to 2024, 616 393 prescriptions for ocular antibiotics were issued to 343 096 children aged 0–5 years. In 2016, the prevalence was 322 per 1000 children aged 0–1 years and 128 per 1000 children aged 2–5 years (Figure 1a). Prevalence decreased sharply in 2020, coinciding with the onset of the COVID‐19 pandemic, before gradually increasing in subsequent years, with a decrease again in 2024. By 2024, the prevalence was 172 per 1000 children aged 0–1 years and 70 per 1000 children aged 2–5 years, corresponding to prevalence ratios of 0.53 (95% confidence interval 0.53 to 0.54) and 0.55 (0.54 to 0.56) compared to the 2016 level.

FIGURE 1.

Prevalence and incidence rates of ocular antibiotic use among Danish children from 2016 to 2024. (A) Annual prevalence of children aged 0–1 and 2–5 years redeeming at least one prescription for ocular antibiotics per 1000 children. (B) Monthly incidence rates of ocular antibiotic treatment episodes per 1000 children. (C) Proportional use of the most commonly prescribed antibiotics from 2016 to 2024.

Incidence trends mirrored prevalence, with a marked decline during the pandemic and a large rebound, particularly in 0‐ to 1‐year‐olds (Figure 1b). Peaks in the winter months were evident, and incidence was consistently higher among children aged 0–1 years. General practitioners issued 86% of treatment episodes.

The distribution of antibiotic types shifted over the study period (Figure 1c). Fusidic acid fell from 64% in 2016 to 34% by 2024. In contrast, chloramphenicol rose from 24% of prescriptions in 2016 to 74% in 2024. Tobramycin declined from 9.5% to 0%. Ciprofloxacin remained stable at around 5%.

In 2024, boys had higher IRs compared to girls across all age groups, although differences were attenuated with increasing child age (Figure 2a). The highest rate was observed in children aged 11–15 months with an IR of 310–351 per 1000 for boys and 260–297 per 1000 for girls. The IR decreased with age, reaching 53 per 1000 for boys and 48 per 1000 for girls by age 5. The number of antibiotic treatment episodes per child in 2024 also varied by age (Figure 2b). In the second year of life, 24% of children received at least one treatment episode, with 19% receiving only one, 3.8% receiving two and 0.9% having three or more treatment episodes. The fewest episodes were observed in 5‐year‐olds.

FIGURE 2.

Stratified incidence rates and treatment episodes of ocular antibiotics in 2024. (a) Incidence rates of ocular antibiotic treatment episodes per 1000 children by sex and age in 1‐month bins. (b) Proportion of children receiving 1, 2 or 3+ antibiotic treatment episodes in 2024, stratified by 1‐year age bins.

Regional variation was substantial. In 2024, the South, Zealand and North Regions had the highest IRs (137, 124 and 122 per 1000 children, respectively), while the Capital Region had the lowest (105 per 1000), corresponding to an incidence rate ratio of 1.30. Municipal rates ranged from below 80 to approximately 200 per 1000 (Figure 3).

FIGURE 3.

Municipal incidence rates of ocular antibiotics in 2024. Incidence rates of ocular antibiotic treatment episodes per 1000 children by Danish municipalities in 2024.

4. Discussion

4.1. Summary of Findings

This study provides contemporary data on trends in ocular antibiotic use among Danish children aged 0–5 years. We observed a significant decline in both prevalence and incidence rates of ocular antibiotic use during the COVID‐19 pandemic, followed by a rebound in 2023 and a decrease in 2024. Chloramphenicol replaced fusidic acid as the most prescribed antibiotic, while the use of tobramycin ceased. Antibiotic use was highest among children aged 0–1 years and varied considerably across regions.

4.2. Discussion of Results

Our results show a marked decrease in ocular antibiotic use in 2020–2021, coinciding with COVID‐19 restrictions. After restrictions were lifted, prevalence and incidence rose sharply, likely reflecting a rebound in infections as exposure to pathogens resumed [7]. A similar pattern was observed in England [8]. In contrast, a Spanish study found stable use in the period and no seasonal variation [9]. Our finding of winter peaks in incidence suggests a seasonal component, potentially linked to higher pathogen transmission during colder months [10]. Despite the rebound, prevalence and incidence rates in 2024 remained below 2016 levels, continuing a declining trend observed since 2000 [5].

Chloramphenicol replaced fusidic acid as the most prescribed antibiotic during the study period. This is due to changes in clinical guidelines, recommending chloramphenicol because of an increased concern about fusidic acid resistance [11]. Tobramycin was removed from the Danish market in 2022, explaining its disappearance [12].

Compared to other Scandinavian countries, Denmark has historically had a higher prevalence of ocular antibiotic use than Norway [5], although the gap has narrowed in recent years [13]. In contrast, Sweden has consistently had a markedly lower prevalence, with 2024 levels (42 per 1000 children), corresponding to about one‐third of the Danish level, possibly reflecting better adherence to clinical guidelines or more conservative prescribing practices [14].

Within Denmark, we found substantial regional and municipal variation, likely reflecting differences in clinical practice, healthcare access or regional guidelines. Socioeconomic factors might also play a role, as municipalities with higher incidence tend to have lower socioeconomic status [15]. Similar patterns have been reported in New Zealand, where higher antibiotic use was observed in more socioeconomically deprived populations [16]. Regional efforts to promote appropriate antibiotic use, such as educational campaigns, have shown success in reducing prescriptions and could be expanded [17]. Initiatives such as Choosing Wisely Denmark may further support this by developing a specific ‘do‐not’ recommendation and raising awareness among clinicians and the public.

Incidence rates were consistently higher among 0‐ to 1‐year‐olds, aligning with the age at which Danish children typically begin day care, likely increasing their exposure to pathogens. This is supported by our finding that the highest proportion of children receiving at least one treatment episode was among children in their second year of life. Day care policies requiring treatment of eye infections before re‐entry may further drive antibiotic prescriptions in this age group [3], despite national guidelines recommending antibiotics only for severe symptoms of bacterial conjunctivitis.

Boys had higher incidence rates across all age groups in early childhood. This pattern is consistent with previous studies on systemic antibiotics [18] and may reflect a higher susceptibility to most respiratory tract infections in boys, which has been attributed to both immunological, anatomical and behavioural differences [19].

Parental expectations and limited knowledge about antibiotics likely also contribute to overuse [3]. In the Capital Region, 74% of general practitioners reported direct parental requests for antibiotics, and 88% experienced indirect pressure [17]. Addressing these factors through education and awareness initiatives could help reduce unnecessary antibiotic use.

4.3. Strengths and Limitations

The strengths of this study include the use of nationwide registry data, which ensures comprehensive coverage and eliminates selection bias. Additionally, the data capture all prescriptions filled at community pharmacies, regardless of the prescriber. Limitations include the lack of knowledge on adherence and the absence of clinical information that enables evaluation of prescribing appropriateness.

5. Conclusion

This study highlights important trends in ocular antibiotic use among young Danish children from 2016 to 2024, supporting a Choosing Wisely Denmark recommendation. A steady decline in use from 2016 to 2019 was followed by a temporary reduction during the COVID‐19 pandemic and a subsequent rebound, ending in a marked decline in 2024. We observed significant geographic variation, possibly linked to socioeconomic factors. These findings underscore the need for continued efforts to promote appropriate use. Addressing parental expectations, standardizing national guidelines, and reducing regional disparities could help optimize prescribing practices and limit unnecessary antibiotic use, thereby contributing to antimicrobial stewardship.

Ethics Statement

According to Danish law, studies based solely on register data do not require ethical approval.

Conflicts of Interest

The authors declare no conflicts of interest.

Sonne H., Pottegård A., Sommerlund K., Raft C., and Kildegaard H., “Ocular Antibiotic Use in Young Danish Children From 2016 to 2024,” Basic & Clinical Pharmacology & Toxicology 137, no. 4 (2025): e70108, 10.1111/bcpt.70108.

Data Availability Statement

Individual‐level data cannot be shared by the authors owing to Danish data protection regulations. De‐identified data can be made available for authorized researchers after application to Forskerservice at the Danish Health Data Authority.