Study finds infants prescribed antibiotics less frequently following implementation of vaccination programs

August 24, 2017

Antibiotics were prescribed less frequently to infants in Denmark after the implementation of national vaccination programs, found a new study led by researchers from the UNC Gillings School of Global Public Health.

Widespread antibiotic use leads to antibiotic resistance, which makes unnecessary antibiotic use a serious threat to public health around the globe. Additionally, the development of “downstream” chronic diseases like asthma and allergies may be linked with early childhood antibiotic use.

Dr. Alan Kinlaw

Dr. Alan Kinlaw

According to the study’s lead author, Alan Kinlaw, PhD, recent graduate of the Gillings School’s Department of Epidemiology and current postdoctoral fellow at the UNC Sheps Center for Health Services Research, prior studies have shown that between 20 and 50 percent of children’s antibiotic prescriptions are written in response to nonbacterial upper respiratory tract infections. Antibiotics generally are ineffective against these kinds of infections, however, providing a perfect example of the kind of unnecessary antibiotic prescribing that needs to be limited.

Amid calls to decrease unnecessary antibiotic use, Kinlaw led a collaboration between the Gillings School, UNC’s School of Medicine and researchers at Aarhus University in Denmark to explore how antibiotic prescribing has changed over time for children born in Denmark. An article with their full findings, titled “Trends in Antibiotic Use by Birth Season and Birth Year,” was published online August 14 in Pediatrics.

“To characterize changes over time in antibiotic prescribing to infants, we analyzed Denmark’s national registry data on more than half a million children born from 2004-2012,” Kinlaw explained. “We had two novel findings. First, antibiotics were prescribed to infants less often after Denmark introduced nationwide pneumococcal vaccination programs in 2007 and 2010. Second, the season in which a child is born has important implications for their subsequent early-life exposure to antibiotics.”

The first finding underscored the importance of vaccines as part of broad antibiotic stewardship campaigns to drive down unnecessary prescribing. Overall, the authors found that the percentage of infants in Denmark who received at least one antibiotic in their first year of life decreased from 40.7 percent of infants born in 2004 to 34.6 percent of infants born in 2012.

The second finding confirmed the researchers’ suspicion that infants received antibiotics most frequently in the winter months, but also revealed that the older infants were when they faced their first winter, the greater their risk of receiving an antibiotic prescription.

“This study was made possible by a strong existing collaboration between several co-authors – most notably my dissertation advisor at UNC, Professor Til Stürmer, and my mentor at Aarhus University, Professor Henrik Toft Sørensen,” Kinlaw shared. “My hope is that our findings will inform future research, both into how vaccines can bolster antibiotic stewardship efforts, and into how some children may be inherently more susceptible to downstream effects of antibiotic exposure based on when they were born.”

Other co-authors from the Gillings School included Til Stürmer, MD, PhD, professor of epidemiology, Jennifer L. Lund, PhD, assistant professor of epidemiology, Julie L. Daniels, PhD, professor of epidemiology and maternal and child health, and Christina D. Mack, PhD, adjunct assistant professor of epidemiology.

Pediatrics also published a two-page commentary on this study written by two prominent leaders in the field.


Gillings School of Global Public Health contact: David Pesci, director of communications, (919) 962-2600 or

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