Table 1.
Global Changes in Pneumococcal Serotype Diversity Among Children Colonized and Infected With Streptococcus pneumoniae Before, During, and After the Introduction of the 7- and 13-Valent Pneumococcal Conjugate Vaccines
| Study, First Author (Year) | Country | Study Population | Age Group | Sample Size | Simpson's D (95% CI) |
|||
|---|---|---|---|---|---|---|---|---|
| Pre-PCV7 Period | Early PCV7 Period | Late PCV7 Period | Post–PCV13 Introduction | |||||
| Black et al (2007) [13] | United States | IPD | <5 y | 519 | 0.864 (.847–.881) | 0.947 (.935–.958) | NR | NR |
| Lacapa et al (2008) [14] | United States | IPD | <5 y | 59 | 0.928 (.919–.937) | 0.940 (.896–.984) | NR | NR |
| Guevara et al (2009) [15] | Spain | IPD | <5 y | 78 | NR | 0.916 (.900–.932) | 0.857 (.789–.925) | NR |
| All ages | 318 | NR | 0.923 (.909–.937) | 0.882 (.855–.909) | NR | |||
| Perez-Trallero et al (2009) [16] | Spain | IPD | <5 y | 91 | 0.901 (.878–.924) | 0.927 (.902–.953) | 0.879 (.804–.954) | NR |
| Kaplan et al (2010) [17] | United States | IPD | <18 y | 1030 | NR | 0.841 (.808–.873) | 0.667 (.618–.716) | NR |
| Wenger et al (2010) [18] | United States | IPD | <5 y | 384 | 0.852 (.822–.883) | 0.917 (.880–.954) | 0.808 (.754–.862) | NR |
| Vestrheim et al (2010) [19] | Norway | Carriage | <5 y | 204 | 0.830 (.790–.871) | 0.940 (.922–.958) | NR | NR |
| Flasche et al (2011) [20] | United Kingdom | Carriage | <5 y | 372 | 0.891 (.878–.904) | 0.960 (.949–.971) | NR | NR |
| Richter et al (2013) [21] | United States | IPD | <5 y | 243 | 0.851 (.823–.879) | 0.900 (.843–.957) | 0.857 (.779–.934) | 0.606 (.452–.760) |
| All ages | 1431 | 0.897 (.885–.908) | 0.906 (.886–.927) | 0.841 (.810–.873) | 0.680 (.630–.729) | |||
| Guevara et al (2014) [22] | Spain | IPD | <5 y | 207 | NR | 0.893 (.869–.917) | 0.871 (.834–.907) | 0.915 (.854–.977) |
| All ages | 688 | NR | 0.930 (.919–.941) | 0.921 (.911–.932) | 0.925 (.909–.942) | |||
| Moore et al (2014)a [23] | United Kingdom | IPD | <2 y | 455 | 0.868 (.846–.891) | 0.927 (.906–.949) | 0.946 (.923–.968) | |
| All ages | 4850 | 0.927 (.923–.931) | 0.941 (.936–.947) | 0.927 (.921–.933) | ||||
| Richter et al (2014) [24] | United States | IPD and carriage | All ages | 3444 | NR | NR | 0.902 (.895–.908) | 0.917 (.911–.923) |
| Moore et al (2015) [12] | United States | IPD | <5 y | 2189 | NR | NR | 0.686 (.605–.768) | 0.883 (.865–.902) |
| 5–17 y | 797 | NR | NR | 0.843 (.802–.884) | 0.870 (.845–.896) | |||
| Stockmann et al (2016) [35] | United States | IPD | <2 y | 266 | 0.910 (.888–.931) | 0.952 (.948–.957) | 0.850 (.819–.881) | 0.913 (.905–.921) |
| 2–4 y | 180 | 0.928 (.921–.933) | 0.935 (.921–.950) | 0.877 (.856–.898) | 0.908 (.903–.913) | |||
| 5–17 y | 168 | 0.920 (.900–.939) | 0.959 (.874–1.000) | 0.872 (.847–.896) | 0.906 (.900–.912) | |||
| All ages | 614 | 0.920 (.903–.937) | 0.949 (.938–.960) | 0.867 (.841–.893) | 0.921 (.913–.929) | |||
Serotype diversity is expressed as Simpson's D, which measures the probability that 2 pneumococcal isolates selected at random, with replacement, from a given time period will be different serotypes. The value of this index ranges between 0 and 1, with larger values representing greater diversity.
Abbreviations: CI, confidence interval; IPD, invasive pneumococcal disease; NR, not reported; PCV7, 7-valent pneumococcal conjugate vaccine; PCV13, 13-valent pneumococcal conjugate vaccine.
a PCV7 was introduced in September 2006 in the United Kingdom, which was followed by the introduction of PCV13 in April 2010. Moore et al reported their serotype data for the 2006–2010 post-PCV7 period in aggregate, and therefore it was not possible to calculate Simpson's D for the early vs late PCV7 periods.