Between 1992 and 1994, the incidence of pneumococcus in Finland increased by 2 fold among children under two years old, and 3 times among children under 16 years old. The authors attribute this to the disappearance of Hib.
During five years after the start of Hib vaccination, the incidence of pneumococcal bacteremia in Philadelphia doubled (from 38 to 73 cases per year). The incidence of hemophilic bacteremia has decreased from 34 to 9 cases per year, and the incidence of meningococcal bacteremia has not changed (3 cases per year).
The incidence of pneumococcal meningitis increased by 50% (from 5.2 to 7.6 cases per year). The incidence of H. influenzae meningitis has decreased from 18 to 5.6 cases per year, and the incidence of meningococcal meningitis has not changed (3 cases per year).
In vitro, pneumococcus has a bactericidal effect on the H. influenzae bacteria. Pneumococcus secretes hydrogen peroxide, which kills the H. influenzae. Pneumococcus also has an inhibitory effect on the meningococcus, which also dies when exposed to hydrogen peroxide, although this requires a higher concentration.
The production of hydrogen peroxide by pneumococcus correlates with the concentration of oxygen in the environment. Other bacteria that secrete hydrogen peroxide are lactobacilli and oral streptococci.
The bacteria that hydrogen peroxide kills or inhibits are Staphylococcus aureus, Gonococcus (a bacterium that causes gonorrhea) and diphtheria.
In those who got pneumococcal vaccines, there are fewer pneumococcal bacteria of non-vaccine serotypes in the upper respiratory tract, but more H. influenzae and staphylococcus, as well as much more anaerobic bacteria. Some of these bacteria are known to increase the risk of otitis media. Temporary bacterial imbalance also increases the risk of otitis media.
Those taking antibiotics had 4 times fewer corynebacteria and Dolosigranulum, but 6.3 times more staphylococcus.
Colonization with pneumococcus negatively correlates with colonization with H. influenzae, and with Staphylococcus aureus colonization.
The authors conclude that elimination of pneumococcus and Haemophilus influenzae due to vaccination may increase the risk of otitis media due to colonization with Staphylococcus aureus, that the effects of this public health intervention can be difficult to predict, and that caution should be exercised in developing strategies to control colonization of the upper respiratory tract.
Pneumococcus colonization among vaccinated and unvaccinated people in Italy did not differ. The H. influenzae bacteria were more often found among vaccinated ones.Effect of 10-valent pneumococcal conjugate vaccine on nasopharyngeal carriage of Streptococcus pneumoniae and Haemophilus influenzae among children in São Paulo, Brazil. 2016, Brandileone, Vaccine
After the start of vaccination, the colonization of vaccine serotypes decreased significantly, but it increased for non-vaccine ones. H. influenzae bacteria were found in vaccinated people 2-5 times more often than in unvaccinated ones. (Sao Paulo, Brazil)Changes in frequency and pathogens causing acute otitis media in 1995-2003. 2004, Casey, Pediatr Infect Dis J
Between 1995 and 2003, the incidence of AOM did not change, but the incidence of protracted AOM decreased from 16% to 12%. Pneumococcus in cases of AOM was replaced by H. influenzae, which after the onset of pneumococcal vaccination became the main causative agent of the disease. (Rochester, New York)Predominance of nontypeable Haemophilus influenzae in children with otitis media following introduction of a 3+0 pneumococcal conjugate vaccine schedule. 2011, Wiertsema, Vaccine
Pneumococcus and H. influenzae are responsible for 80% of cases of AOM. M. catarrhalis is responsible for 3-20% of cases. After the start of vaccination against pneumococcus, most cases of AOM are caused by nonencapsulated serotypes of H. influenzae.Effect of pneumococcal conjugate vaccine on nasopharyngeal bacterial colonization during acute otitis media. 2006, Revai, Pediatrics
The previous study is widely cited, and it is not necessary to even mention that statistical significance was absent. It is also not necessary to mention other studies where the incidence of otitis media in vaccinated individuals has been increased.
In addition, it is reported that the colonization of pneumococcus during otitis media has not changed, since vaccine serotypes have been replaced by non-vaccine ones.
The bacterium M. catarrhalis was found more often in the middle ear in vaccinated children, compared with unvaccinated ones.
Of the three types of bacteria (pneumococcus, hemophilic bacillus and M. catarrhalis), an average of 1.37 bacterial species were found in unvaccinated, 1.48 in partially vaccinated, and 1.67 in vaccinated.