Volume 18, Number 11—November 2012
CME ACTIVITY - Research
Invasive Pneumococcal Disease and 7-Valent Pneumococcal Conjugate Vaccine, the Netherlands
Table 1
Incidence of invasive pneumococcal disease before and after implementation of a PCV7 vaccination program, the Netherlands, June 2004–May 2010*
Age group, y |
Vaccination period†
|
Late post- vs. pre-implementation period
|
||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Pre-implementation
|
Early post- implementation
|
Late
post-implementation
|
||||||||||
No. cases | Incidence | No. cases | Incidence | No. cases | Incidence | IRR | 95% CI | p value | ||||
All serotypes | ||||||||||||
All ages |
1,216 | 14.9 | 1,304 | 15.9 | 1,144 | 13.8 | 0.93 | 0.86–1.01 | NS | |||
<2 |
68 | 35.0 | 42 | 22.8 | 26 | 14.1 | 0.40 | 0.26–0.63 | <0.001 | |||
2–4 |
25 | 8.2 | 26 | 8.9 | 12 | 4.3 | 0.52 | 0.26–1.04 | NS | |||
5–17 |
23 | 1.8 | 22 | 1.7 | 23 | 1.8 | 1.00 | 0.56–1.78 | NS | |||
18–49 |
181 | 4.9 | 209 | 5.8 | 197 | 5.5 | 1.11 | 0.91–1.36 | NS | |||
50–64 |
253 | 16.4 | 292 | 18.3 | 261 | 15.8 | 0.96 | 0.81–1.14 | NS | |||
>65 |
666
|
57.7
|
|
713
|
59.6
|
|
625
|
49.9
|
|
0.87
|
0.78–0.97
|
0.009
|
PCV7 serotypes | ||||||||||||
All ages |
565 | 6.9 | 561 | 6.9 | 268 | 3.2 | 0.47 | 0.40–0.54 | <0.001 | |||
<2 |
48 | 24.7 | 15 | 8.1 | 0 | 0.0 | 0 | NA | <0.001 | |||
2–4 |
17 | 5.6 | 17 | 5.8 | 3 | 1.1 | 0.19 | 0.06–0.66 | 0.003 | |||
5–17 |
11 | 0.9 | 4 | 0.3 | 4 | 0.3 | 0.36 | 0.12–1.14 | NS | |||
18–49 |
56 | 1.5 | 66 | 1.8 | 48 | 1.3 | 0.87 | 0.59–1.29 | NS | |||
50–64 |
114 | 7.4 | 129 | 8.1 | 56 | 3.4 | 0.46 | 0.33–0.63 | <0.001 | |||
>65 |
319
|
27.6
|
|
330
|
27.6
|
|
157
|
12.5
|
|
0.45
|
0.37–0.55
|
<0.001
|
Non–PCV7 serotypes | ||||||||||||
All ages | 650 | 8.0 | 741 | 9.1 | 876 | 10.6 | 1.33 | 1.20–1.47 | <0.001 | |||
<2 |
20 | 10.3 | 27 | 14.7 | 26 | 14.1 | 1.37 | 0.77–2.46 | NS | |||
2–4 |
8 | 2.6 | 9 | 3.1 | 9 | 3.2 | 1.22 | 0.47–3.18 | NS | |||
5–17 |
12 | 0.9 | 18 | 1.4 | 19 | 1.5 | 1.58 | 0.77–3.26 | NS | |||
18–49 |
125 | 3.4 | 142 | 3.9 | 149 | 4.1 | 1.22 | 0.96–1.54 | NS | |||
50–64 |
139 | 9.0 | 163 | 10.2 | 205 | 12.4 | 1.37 | 1.11–1.70 | 0.004 | |||
>65 |
346 | 30.0 | 382 | 32.0 | 468 | 37.4 | 1.25 | 1.09–1.43 | 0.002 |
*Cases are number of patients included in a study covering ≈25% of the Dutch population; incidence is number of cases/100,000 persons. Three pneumococcal isolates (1 in the pre- and 2 in the early post-implementation period) were either not typeable or typed as a rough strain and, therefore, could not be classified as 7-valent pneumococcal conjugate vaccine (PCV7) or non–PCV7 serotypes. IRR, incidence rate ratio; NS, not significant (p>0.05); NA, not applicable; boldface, significant difference (p<0.05).
†Vaccination periods: pre-implementation period, June 2004–May 2006; early post-implementation, June 2006–May 2008; late post-implementation period, June 2008–May 2010.
1These authors contributed equally to this article.
2These authors contributed equally to this article.
3Additional members of the Invasive Pneumococcal Disease Sentinel Surveillance Laboratory Group are listed at the end of this article.
Members of the Invasive Pneumococcal Disease Sentinel Surveillance Laboratory Group: Karola Waar, Izore, Centre for Infectious Diseases Friesland, Leeuwarden, the Netherlands; Bert Mulder, Laboratory of Medical Microbiology Twente Achterhoek, Enschede, the Netherlands; Caroline Swanink, Department of Medical Microbiology and Medical Immunology Hospital Rijnstate, Arnhem, the Netherlands; Bram Diederen, Regional Laboratory of Public Health, Haarlem, the Netherlands; Niek Arents, Laboratory for Pathology and Medical Microbiology, Veldhoven, the Netherlands; Ine Frénay, Regional Laboratory for Medical Microbiology and Infectious Diseases, Dordrecht–Gorinchem, the Netherlands; Hans Wagenvoort, Atrium Medical Center, Heerlen, the Netherlands; Bartelt de Jongh, St. Antonius Hospital, Nieuwegein, the Netherlands; Lodewijk Spanjaard, Academic Medical Center, Amsterdam, the Netherlands