Investigators from Rochester General Hospital Research Institute and Rochester Institute of Technology, both in Rochester, NY, conducted a retrospective cohort study to assess the association between vaccine-induced antibody levels and antibiotic use in young children. Data for the current analysis were obtained originally during a study on respiratory infections in children. Participants were patients, 6-24 months old during the period 2006–2016, seen at a pediatric practice in suburban Rochester, NY. For that study, antibody levels to antigens in diphtheria-tetanus-acellular pertussis (DTaP), Haemophilus influenza type b (Hib), inactivated polio virus (IPV), and pneumococcal conjugate vaccine (PCV, including serotypes 6B, 14, and 23 F) were obtained at 9,12, 15, 18, and 24 months of age. Use of antibiotics in study children was documented through medical record review and contact with parents. For the current study, children who completed study visits through 24 months of age and had at least 1 blood sample for vaccine-induced antibody levels obtained were included. Those with 1 or more antibiotic prescription during the study period were assigned to the antibiotic cohort, and those with no prescriptions to the no antibiotic cohort. Using established criteria for defining protective vaccine-induced antibody levels, the percentage of levels below protective levels between 9 and 24 months were compared by Mann-Whitney tests; analyses for each vaccine antigen, all vaccine-induced antibodies combined at different ages, and when levels were obtained within 30 days of exposure to specific antibiotics, were conducted. To evaluate the cumulative effect of antibiotics on vaccine antibody levels, multivariate linear regression was used to compare vaccine-induced antibody levels in children at 18-24 months of age with number of antibiotic prescriptions, after controlling for confounders.
A total of 11,888 vaccine antibody levels were obtained on 560 children, with 342 in the antibiotics cohort and 218 with no antibiotic prescriptions. The percentage of vaccine-induced antibody levels that were lower than the threshold protective level was significantly higher in those in the antibiotics cohort than in those in the no antibiotics cohort for 3 DTaP antigens (diphtheria toxoid, tetanus toxoid and pertussis toxoid) and PCV serotype 23F. There was also a significantly higher percentage of all-vaccine antibody levels below threshold protective levels among children in the antibiotic cohort at 9 and 12 months of age. Recent (<30 days) exposure to each of the following antibiotics: ceftriaxone, cefdinir, and amoxicillin/clavulanate, was associated with a significantly higher percentage of vaccine-induced antibody levels below protective levels. Overall, each antibiotic prescription was associated with a reduction of vaccine-induced antibody levels at 18-24 months of age by 181% for DTaP (P <0.001), 21.3% for Hib (P = 0.02), 18.9% for IPV (P = 0.02), and 12.2% for PCV (P = 0.03).
The authors conclude that antibiotic use in children <2 years old was associated with lower vaccine-induced antibody levels to several...