Children who receive antibiotics at an early age have lower vaccine-induced antibody response to many childhood vaccines, suggests a new study published in the journal Pediatrics.¹

Researchers from the Rochester General Hospital Research Institute, Center for Infectious Diseases and Immunology in Rochester, New York retrospectively reviewed medical records of children aged 6-24 months, to examine them for antibiotic prescriptions and antibodies to diphtheria-tetanus-acellular pertussis (DTaP), inactivated polio (IPV), Haemophilus influenzae type b (Hib), and pneumococcal conjugate (PCV) vaccines. A total of 560 children were enrolled from 2006 to 2016; of these, 342 were prescribed 1678 antibiotic courses, while the remaining 218 did not receive antibiotics.

The study found that children who had been treated with antibiotics (mainly amoxicillin, amoxicillin-clavulanate, cefdinir, and ceftriaxone) showed lower levels of vaccine-induced antibody levels to vaccines; this negative association was particularly evident at 9 and 12 months of age.

The decline in antibodies was proportional to the number of antibiotics prescribed. Antibodies were below protective levels following treatment with broad-spectrum antibiotics and longer duration of therapy. Children who had been prescribed antibiotics more frequently also showed lower levels of antibodies.

After each course of antibiotics, the prebooster antibody levels to DTaP vaccine were reduced by 5.8%, Hib vaccine by 6.8%, IPV vaccine by 11.3% and PCV by 10.4%. Post boosters, the antibody levels to DTaP antigens decreased by 18.1%, Hib by 21.3%, IPV by 18.9% and PCV by 12.2%.

The probability of being prescribed antibiotics was higher in children in day care; nearly 43% of children who received antibiotics were in daycare compared to 20.6% who hadn’t received any antibiotics

This first-of-its-kind study has shown that the use of antibiotics in children younger than 2 years of age is associated with reduced effectiveness of common childhood vaccinations. It further provides evidence-based support for antibiotic stewardship by advocating judicious use of antibiotics in infants and toddlers.

Reference

1. Chapman TJ, et al. Antibiotic use and vaccine antibody levels. Pediatrics. 2022 Apr 27;e2021052061. doi: 10.1542/peds.2021-052061.