Close to half of all infants have an episode of acute otitis media by age 1 year, but incidence appears to have dropped in the pneumococcal conjugate vaccine era, a recent study found.
“We clearly showed that frequent viral infections, bacterial colonization, and lack of breastfeeding are major acute otitis media (AOM) risk factors,” reported Dr. Tasnee Chonmaitree and her associates at the University of Texas Medical Branch in Galveston (Pediatrics 2016 March 28 doi: 10.1542/peds.2015-3555). “It is likely that medical interventions in the past few decades, such as the use of pneumococcal and influenza virus vaccines, higher breastfeeding rates and decreased smoking, helped reduce AOM incidence.”
Between October 2008 and March 2014, researchers began tracking 367 infants from birth until they experienced their first case of AOM (and then on to age 6 months) or until they reached age 12 months; 85% completed the study. Preterm infants and those with anatomic defects or major medical problems were not included. The researchers collected nasopharyngeal specimens once during each of the first 6 months, once in the child’s 9th month, and during any viral upper respiratory infections to conduct bacterial cultures and viral polymerase chain reactions for 13 respiratory viruses.
During the course of the study, 305 children experienced a total of 887 upper respiratory infections, and 143 children experienced a total of 180 AOM episodes. Upper respiratory infections occurred at a rate of 3.2 episodes per child per year, and lower respiratory infections occurred at a rate of 0.24 episodes per child per year. Clinical sinusitis complications followed 4.6% of the upper respiratory infections, and lower respiratory infections followed 7.6%.
The rate of AOM was 0.67 episodes per child per year. Although only 6% of the infants had experienced AOM by age 3 months, that rose to nearly a quarter (23%) of the children at age 6 months and nearly half (46%) at age 12 months. Still, it remained below the rates of 18% by 3 months and 30%-39% by 6 months that had been reported in the late 1980s and 1990s.
Children who had AOM experienced 4.7 upper respiratory infections per year, compared with 2.3 episodes per year in children without AOM (P less than .002). They also had significantly greater pathogenic bacterial colonization overall and for Haemophilus influenzae and Moraxella catarrhalis, in their monthly nasopharyngeal specimens, although Streptococcus pneumoniae rates were not significantly greater.
“Interestingly, we found that not only viruses increased upper respiratory infection risk; M. catarrhalis and S. pneumoniae also increased upper respiratory infection risk,” the authors wrote “On the other hand, we found better protection for S. pneumoniae (infants born after 2010) associated with decreased upper respiratory infection risk.”
Upper respiratory infections were 74% more likely among children attending day care, and 7% more likely among children with at least one sibling at home. These infections were 37% less likely in children exclusively breastfed at least 6 months, 16% less likely in children born after February 2010, and 4% less likely for each month of any breastfeeding.
Similarly, AOM episodes were 60% less likely in children exclusively breastfed at least 3 months, and 15% less likely for each month children were breastfed.
The research was funded by the National Institutes of Health. The authors reported no disclosures.