Antibiotics linked to less effective childhood vaccines


A study published yesterday (April 27) in Pediatrics finds that children who received a course of antibiotics during the first two years of life had diminished immune responses to four common vaccines. Researchers say Scientific news that the results are a cautionary tale about the overuse of antibiotics.

Babies are usually immunized against various diseases during the first six months of life and receive boosters during their second year. From 2000 to 2016, the study authors took blood samples from 560 children aged 6 to 24 months during routine visits to their pediatrician, measuring antibody levels after the children received polio, diphtheria-tetanus-pertussis, Haemophilus influenzae type b and pneumococcal vaccines.

Of these children, 342 had collectively been prescribed nearly 1,700 courses of antibiotics. The other 218 children had not received antibiotics. The team analyzed whether antibody levels induced by the four vaccines reached the threshold of what is considered protective and found that at 9 and 12 months, children who received a course of antibiotics were significantly more likely to have lower antibody levels than those who did not. Immune response was weaker in children who had multiple courses of antibiotics than in those who had one course, with each antibiotic dose associated with 5-11% lower antibody levels after initial vaccinations and 12 to 21% lower antibodies after booster injections. .

The study did not assess actual rates of disease in children, and some studies noted that antibody levels are sometimes imperfect predictors of immune protection against disease.

“If anyone needed another reason why overprescribing antibiotics is not a good thing, this article offers that reason,” said immunologist Bali Pulendran of Stanford University School of Medicine, who did not participate in the study. Science News.

The association varied by type and duration of antibiotic treatment. Broad-spectrum drugs, which target a wide range of bacteria, were associated with lower than protective levels of antibodies, unlike more targeted antibiotics. Ten-day courses, but not five-day courses, were associated with vaccine-induced reduced antibody levels.

Antibiotics are known to affect the gut microbiome, which in turn influences a wide range of bodily systems, including the immune system. The study authors suggest that antibiotics could negatively affect children’s gut health by decreasing the diversity of bacteria in the gut, which in turn could decrease vaccine effectiveness. Scientific news reports that this new study adds to existing evidence that gut health can affect response to vaccination.

See “Gut Microbes Boost Flu Vaccine Success: Clinical Trial”

According to Scientific News, Study co-author Michael Pichichero, a pediatric infectious disease specialist at the Rochester General Hospital Research Institute in New York, and his colleagues are starting a study with a new group of children to see what kinds of changes occur in the intestinal bacteria. The researchers plan to collect stool samples as well as blood draws and records of antibiotic use. They would like to follow children after age 5, beyond when children receive another round of boosters, to find out if antibiotics also interfere with this next opportunity to develop antibodies.

“Antibiotics are miracle drugs”, says Pichichero Scientific news. “This study in no way implies that children who need an antibiotic should not take it.”


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