The pneumococcal vaccine is routinely administered to babies in the United States starting at 2 months of age.
The rate of acute otitis media (AOM) in children in the United States has declined “threefold” in the past decade (when compared with infections in the 1980s) and the results of a recent study point to pneumococcal vaccines as the cause.
That’s the good news. The bad news is that the researchers also found that the types of bacteria that are causing the majority of ear infections today are not targeted by these vaccines. And, perhaps more alarming, these bacteria are not killed by amoxicillin, the first-line antibiotic recommended to treat the infections.
Michael Pichichero, MD, study author and director of the Rochester General Hospital Research Institute, Rochester, NY, remarked on these findings in the press release, stating, “The magnitude of the drop in the occurrence of ear infections was more than I expected. The second big finding is we've got this shift in the number 1 bacteria. If something is not done, I would expect ear infections to come back in frequency.”
The American Academy of Pediatrics reports that > 5 million ear infections occur in children in the United States each year. These infections result in > 10 million prescriptions for antibiotics and around 30 million medical care visits. The study authors note that Streptococcus pneumoniae is the most common cause of these infections.
For their study, Dr. Pichichero and his team looked at more than 600 children from 2006 to 2016. A total of “23% of the children experienced at least 1 ear infection, and 3.6% had at least 3 ear infections by 12 months of age. By the age of 3, about 60% of the children had 1 or more ear infections, and about 24% had 3 or more ear infections,” according to the press release.
These rates are still lower than was reported 30 years ago, and the researchers point to the introduction of the pneumococcal vaccine, which kills Streptococcus pneumoniae, as the cause. First introduced in 2000, and then “improved with a version that enhanced its effectiveness by protecting for additional strains of the bacteria,” in 2010, the pneumococcal vaccine is “routinely administered to babies in the United States as part of check-ups at 2, 4 and 6 months of age, with a booster given at 12 to 15 months,” according to Dr. Pichichero. (Only 1 dose is required for adults receiving the vaccine.)
Despite the positive effect of reducing ear infections caused by Streptococcus pneumoniae, the vaccines have opened the door for infections with other types of bacteria, namely, Haemophilus influenza and Moraxella catarrhalis. Because these bacteria are not killed by amoxicillin, Dr. Pichichero and his team began prescribing amoxicillin clavulanate, or cefdinir, if the child was allergic to amoxicillin.
Dr. Pichichero also notes that, “the rate of ear infections in children has also dropped because more strict criteria are now used to diagnose the condition.”
He remarked on this in the press release, stating, “Those are two really good things occurring, and the impact has been really significant in reducing the number of ear infections we're seeing. The germs causing ear infections are clever, and the antibiotics and vaccines we're giving are still not perfect, so ... clinical research is continuing so we will eventually conquer all ear infections in children."
Other effects, such as decreased incidence in meningitis and sepsis, as well as other infections caused by Streptococcus pneumoniae have also been noted as a result of pneumococcal vaccines.
Despite the positive effects seen from the vaccine, the risk factors for ear infections remain the same. According to the press release, these include: “day care; family history of ear infections; being a boy; being white; and getting a first ear infection before 6 months of age.”