Impact of pneumococcal vaccines use on invasive pneumococcal disease in Nunavik (Quebec) from 1997 to 2010

Figures & data

Fig. 1 Number of cases of invasive pneumococcal disease in children less than 5 years of age in Nunavik: number of cases by year (total and by serotype), 1997–2010.

Fig. 2 Number of cases of invasive pneumococcal disease in persons aged 5 years or more in Nunavik: number of cases by year (total and by serotype), 1997–2010.

Table I. Number of cases and incidence rate of invasive pneumococcal disease in children less than 5 years of age in Nunavik, Quebec, by period, 1997–2010

	Number of cases (% total)			Incidence rate per 100,000 person-years
Serotypes	1997–2001	2002–2003	2004–2010	1997–2001	2002–2003	2004–2010	Rate ratio 2004–2010 vs. 1997–2001 (p-value)
All serotypes	13 (100%)	8 (100%)	12 (100%)	191	294	119	0.62 (0.32)
PCV7 types	11 (84%)	3 (38%)	1 (8%)	162	110	10	0.06 (<0.01)
Non-PCV7 types	2 (16%)	5 (62%)	11 (92%)	29	183	109	3.72 (0.11)
Serotype 1	0 (0%)	1 (12%)	0 (0%)	0	37	0	–
Serotype 19A	1 (8%)	2 (25%)	4 (33%)	15	73	40	2.71 (0.66)
Others	1 (8%)	2 (25%)	7 (59%)	15	73	70	4.74 (0.21)

Table II. Number of cases and incidence rate of invasive pneumococcal disease in persons ≥5 years of age in Nunavik, Quebec, by period, 1997–2010

	Number of cases (% total)			Incidence rate per 100,000 persons-year
Serotypes	1997–2001	2002–2003	2004–2010	1997–2001	2002–2003	2004–2010	Rate ratio 2004–2010 vs. 1997–2001 (p-value)
All serotypes	20 (100%)	12 (100%)	17 (100%)	49	68	25	0.51 (0.06)
PCV7 types	6 (30%)	1 (8%)	2 (12%)	15	5.5	3	0.20 (0.07)
PPSV23 types (not included in PCV7)	14 (70%)	10 (84%)	9 (53%)	34	57	13	0.39 (0.04)
Serotype 1	12 (60%)	10 (84%)	1 (6%)	29	57	1.5	0.05 (<0.01)
Serotype 19A	0 (0%)	0 (0%)	2 (12%)	0	0	3	+∞^† (0.78)
Others	2 (10%)	0 (0%)	6 (35%)	5	0	8.5	1.8 (0.73)
Non-PCV7 or PPSV23 types	0 (0%)	1 (8%)	6 (35%)	0	5.5	9	+∞^† (0.12)

^†No case occurred during the period from 1997 to 2001, so by definition the rate ratio is infinite.

Table III. Number of cases of invasive pneumococcal disease in persons ≥5 years of age in Nunavik, Quebec (July 2002–December 2010), following the end of the mass immunization campaign using the 23-valent polysaccharide vaccine (PPSV23)

	PPSV23-types					Non-PPSV23-
Serotypes	1	7F	19A	Others	All	types	Total
Number of cases	9	2	2	5^†	18	8^††	26
Vaccinated with PPSV23	6	1	1	2	10	6	16
Mean interval in years between vaccination and disease onset (range)	1.5 (0.7–2.4)	13.8	8.6	11.2 (7.6–14.8)	5.4 (0.7–14.8)

^†Serotypes 3, 4, 9N, 10A and 20.

^††Serotypes 16F (2 cases), 6A, 15A, 15C, 21, 22A, 23A.