Uptake of Pneumococcal Vaccines in The Nordic Region of Nunavik, Province of Quebec, Canada
Uptake of Pneumococcal Vaccines in The Nordic Region of Nunavik, Province of Quebec, Canada
Uptake of Pneumococcal Vaccines in The Nordic Region of Nunavik, Province of Quebec, Canada
ABSTRACT
OBJECTIVES: Pneumococcal infections constitute an important public health problem in Nordic regions of Canada. Nordic populations are not
included in national and provincial immunization surveys and there is no centralized immunization registry in these regions. The objective of this study
was to estimate pneumococcal vaccination coverage and delays in immunization of children in Nunavik, Quebec.
METHODS: Immunization records of children born in 1994-2005 were collected in all villages. Children were classified into three groups: born in the
period January 1, 1994 to April 30, 1997 and targeted by the 2002 mass campaign with the 23-valent polysaccharide vaccine (PPSV23); born in the
period May 1, 1997 to March 31, 2002 and targeted by the 7-valent conjugate vaccine (PCV7) catch-up campaign; born in the period April 1, 2002 to
December 31, 2005 and targeted by the PCV7 routine infant program.
RESULTS: In the first group (n=896), 86.8% (95% CI: 84.4%-89.0%) were vaccinated with PPSV23. In the second group (n=1,252), 84.3% (95% CI:
82.1%-86.2%) received 1 PCV7 dose. In the third group, 90.4% (95% CI: 88.5%-92.1%) received 4 PCV7 doses. Delays >4 weeks in vaccine
administration were observed for 26.3% of doses. There were substantial variations between villages for all indicators.
CONCLUSIONS: In the challenging setting of a Nordic and remote region, uptake rates of pneumococcal vaccines in Nunavik were found to be similar
to those measured in population surveys in Quebec.
KEY WORDS: Streptococcus pneumoniae; pneumococcal vaccines; immunization; infectious diseases; Aboriginal health
La traduction du rsum se trouve la fin de larticle. Can J Public Health 2014;105(4):e268-e272.
R
espiratory infections constitute a major public health results pertaining to pneumococcal vaccine uptake and delays in
problem in Nordic communities of Canada and Streptococcus vaccine administration in different cohorts of births in the
pneumoniae (Sp) is an important causal pathogen.1,2 In 2000, 14 villages of Nunavik.
an outbreak of severe pneumonia caused by serotype 1 Sp was
identified in the Inuit population of Nunavut and Nunavik.3,4 METHODS
Nunavik is the most northerly region of the province of Quebec. The study population included all children born in the period
Approximately 90% of its population (n12,000) are Inuit, living January 1, 1994 to December 31, 2005 and registered by the
in 14 villages located along the Hudson and Ungava bays. In public health services of the region of Nunavik. There is a
order to control this outbreak, a mass immunization campaign primary care health centre in each village where immunization
was carried out during the spring of 2002, targeting persons cards are kept. There is no centralized computerized system for
5 years of age and using the 23-valent pneumococcal immunization in the region. In 2008, copies of immunization
polysaccharide vaccine (PPSV23).5 At the same time, the 7-valent
Author Affiliations
pneumococcal conjugate vaccine (PCV7) was introduced for the 1. Department of Social and Preventive Medicine, Universit Laval, Quebec City, QC
routine immunization of infants (4 doses, offered respectively at 2. Quebec University Hospital Research Centre, Quebec City, QC
3. Public Health Directorate, Nunavik Regional Board of Health and Social Services,
2, 4, 6 and 18 months of age) with a catch-up for children less Kuujjuaq, QC
than 5 years of age. 6 The 10-valent pneumococcal conjugate 4. Quebec Heart and Lung Institute Research Centre, Quebec City, QC
Correspondence: Dr. Philippe De Wals, Dpartement de Mdecine sociale et
vaccine (PCV10) replaced PCV7 in the summer of 2009, and the
prventive, Universit Laval, CRIUCPQ, 2725, Chemin Ste-Foy, Qubec, QC G1V
13-valent vaccine (PCV13) replaced PCV10 in January 2011.7 In 4G5, Tel: 418-656-8711, ext. 3248, E-mail: philippe.dewals@criucpq.ulaval.ca
Acknowledgement: The authors thank all the health professionals in Nunavik who
order to assess the impact of pneumococcal vaccines on the
participated in the data collection.
epidemiology of invasive pneumococcal diseases, lower tract Funding: This study was funded by the International Polar Year Program of the
Canadian Government, administered by the Canadian Institutes of Health Research
respiratory infections and otitis media, knowledge of
(Contract # 2008 04 POL 193340 CFBA 56916). The sponsor had no role in the
pneumococcal vaccine uptake in different segments of the design and conduct of the study, collection, management, analysis and interpretation
of the data, or preparation, review and approval of the manuscript.
population is essential.
Conflict of Interest: During the last year, Philippe De Wals received research grants
As part of the International Polar Year Initiative, 8 a and reimbursements of travel expenses from vaccine manufacturers, including
Glaxo-Smith-Kline, Novartis, Sanofi Pasteur, Merck and Pfizer, as well as from
retrospective study was performed, targeting children residing in
governmental agencies, including the Quebec Ministry of Health and Social Services and
Nunavik and born during the period 1994 to 2005. We report the Public Health Agency of Canada. None of the other authors have conflicts to declare.
e268 REVUE CANADIENNE DE SANT PUBLIQUE VOL. 105, NO. 4 Canadian Public Health Association, 2014. All rights reserved.
PNEUMOCOCCAL VACCINE IN NUNAVIK
Table 1. Uptake rate of PCV7 according to the number of doses among 1,075 children born in the period April 1, 2002 to
December 31, 2005, who were targeted by the routine immunization program implemented in the spring of 2002,
Nunavik, province of Quebec, Canada
Number of Village and number of children
doses 1 2 3 4 5 6 7 8 9 10 11 12 13 14 All
administered N=56 N=171 N=133 N=74 N=198 N=41 N=52 N=24 N=132 N=57 N=44 N=55 N=28 N=10 N=1075
0 dose 10.7% 2.3% 1.4% 9.6% 2.4% 1.9% 5.3% 2.3% 1.8% 14.3% 4.2%
1 dose 89.3% 97.7% 100% 98.6% 90.4% 97.6% 98.1% 100% 95.7% 100% 97.7% 98.2% 85.7% 100% 95.8%
2 doses 89.3% 97.7% 100% 97.3% 89.9% 95.1% 98.1% 100% 91.7% 100% 97.7% 98.2% 85.7% 100% 95.0%
3 doses 89.3% 97.7% 99.2% 97.3% 86.9% 92.7% 98.1% 95.8% 87.9% 100% 97.7% 98.2% 85.7% 100% 93.9%
4 doses 87.5% 94.2% 97.7% 97.3% 83.3% 90.2% 92.3% 95.8% 80.3% 100% 97.7% 98.2% 85.7% 90.0% 91.0%
Total doses
administered 199 662 528 289 692 154 201 94 468 228 172 216 96 39 4038
Proportion
with delay
4 weeks 32.7% 18.3% 35.4% 14.9% 29.5% 17.5% 23.4% 24.5% 40.2% 21.1% 30.2% 10.2% 31.3% 17.3% 26.3%
Figure 1. Cumulative frequency by age at 1st, 2nd, 3rd and 4th PCV7 dose among 1,252 children born in the period May 1, 1997 to
March 31, 2002, who were targeted by the catch-up program implemented in the spring and summer of 2002, Nunavik,
province of Quebec, Canada
cards were obtained; in 2011, all 14 primary care health centres the recommendation of the Canadian Immunization Registry
were visited and immunization cards reviewed. The information Network,9,10 a delay in vaccine administration was defined as a
collected included names, village of residence, date of birth, sex, dose given more than 4 weeks after the recommended age. The
type of pneumococcal vaccine received and date of study protocol was approved by the Quebec University
administration up to the 5th birthday anniversary. Children were Hospital Research Ethics Committee and by the Directors of
classified into in 3 groups: i) those born in the period January 1, 1994 the two regional health centres of Nunavik (Inuulitsivik Health
to April 30, 1997 and targeted by the 2002 mass campaign with Centre, Puvirnituk, and Ungava Tulattavik Health Centre,
PPSV23; ii) those born in the period May 1, 1997 to March 31, 2002 Kuujjuaq).
and targeted by the PCV7 catch-up campaign initiated in the
spring of 2002; and iii) those born in the period April 1, 2002 to RESULTS
December 31, 2005 and targeted by the PCV7 routine infant A total of 3,505 children born in the period January 1, 1994 to
program. Immunization rates according to the number of doses December 31, 2005 and who had resided in Nunavik during the
received were calculated by village and cohort of birth. first five years of their life were identified. Of these, 280 children
Va c c i n e u p t a k e r a t e b y v a c c i n e d o s e a n d e x a c t 9 5 % (8.0% of the total) were excluded because their medical file or
confidence intervals were computed with R statistical software immunization card was not found or was grossly incomplete,
2.12.1 (R Foundation for Statistical Computing, Vienna, signaling an early death, an early departure or a transitory stay in
Austria). Cumulative vaccine coverage curves by age (in days the region. Thus, the statistical analysis included 3,223 children;
and converted into months) were also calculated. According to 48.9% were female (1,576/3,211 whose sex was indicated).
Figure 2. Cumulative frequency by age (in days) at 1st, 2nd, 3rd and 4th PCV7 dose among 1,075 children born in the period April 1, 2002
to December 31, 2005, who were targeted by the routine immunization program implemented in the spring of 2002,
Nunavik, province of Quebec, Canada
Group I 3 villages, rates were lower than 90%, with a minimum of 80.3%
Of 896 children born in the period January 1, 1994 to April 30, in one village. Overall, the proportion of children who did not
1997, 86.8% (95% CI: 84.4%-89.0%) were vaccinated with receive at least one PCV7 dose was 4.2%, ranging from a
PPSV23 during the 2002 mass immunization campaign and minimim of 0% to a maximum of 14% according to villages.
9 received a second dose later (probably because of the existence The cumulative frequency by age at 1st, 2nd, 3rd and 4th PCV7
of a high-risk condition). None of these children received PCV7 dose is shown in Figure 2. The overall one-dose coverage was
before their 5th year anniversary. 95.8% (95% CI: 94.4%-96.9%) at 2 years and 96.3% (95% CI:
95.0%-97.3%) at 5 years. 94.9% received at least 2 doses before
Group II 2 years of age (95% CI: 93.4%-96.1%) and 95.4% before 5 years
There were 1,252 children born in the period May 1, 1997 to (95% CI: 94.0%-96.6%). 94.0% received at least 3 doses before
March 31, 2002, who were targeted by the PCV7 catch-up 2 years of age (95% CI: 92.5%-95.4%) and 94.4% before 5 years
program. The cumulative frequency by age of 1st, 2nd, 3rd and 4th (95% CI: 92.9%-95.7%). 87.0% (95% CI: 84.8%-88.9%) received
PCV7 dose is shown in Figure 1. All of these children should have the recommended 4 doses before 2 years of age and 91.3%
received at least one PCV7 dose and the overall 1 dose coverage (95% CI: 89.5%-93.0%) before 5 years.
was 84.3% (95% CI: 82.1%-86.2%). The recommended number of Overall, 17.1% of vaccinated children received their 1st PCV7
PCV7 doses varied according to the age of each child when seen dose more than four weeks after the age of 60 days. Delays
at a vaccination clinic. Only 11.7% (95% CI: 10%-13.7%) had tended to increase for the following doses: 26.2% for the 2nd dose,
received four doses before their 5th birthday anniversary. 27.4% for the 3rd dose, and 33.3% for the 4th dose. Overall, 26.3%
of doses were administered with a delay of more than 4 weeks,
Group III the proportion ranging from a minimim of 10.2% to a maximum
There were 1,075 children born in the period April 1, 2002 to of 40.2% according to villages (Table 1).
December 31, 2005, who were targeted by the routine 4-dose
PCV7 program implemented in the spring of 2002. The DISCUSSION
distribution of children according to the number of doses The implementation of the pneumococcal conjugate vaccine
received in each of the 14 villages is shown in Table 1. Overall, program in December 2004 in the province of Quebec (16 out of
87.0% (95% CI: 84.8%-88.9%) of children received the 18 health regions) was highly successful in terms of coverage
recommended number of doses by age 2 years and 91.3% rates, both in infants targeted by the routine 3-dose program and
(95% CI: 89.5%-93.0%) by age 5 years. There was no statistically older children targeted by the catch-up campaign.11 Results of the
significant difference between girls and boys (87.6% vs. 85.6% by 2012 Quebec provincial immunization survey showed that 93.1%
age 2 years, p=0.37; 91.7% vs. 90.2% by age 5 years, p=0.43). In of children are receiving the recommended 3 doses by age
6 of 14 villages (43%), the 95% coverage target was achieved. In 2 years. 12 Results of the current study confirm that the
RSUM
OBJECTIFS : Les infections pneumococciques reprsentent un important
problme de sant publique dans les rgions nordiques du Canada. Les
populations nordiques ne sont pas incluses dans les enqutes de
couverture vaccinale nationales et provinciales. Un registre centralis de
couverture vaccinale nexiste pas dans ces rgions. Lobjectif de cette
tude tait dobtenir des estims de couverture vaccinale
pneumococcique et des retards vaccinaux chez les enfants du Nunavik,
Qubec.
MTHODOLOGIE : Les donnes de couverture vaccinale des enfants ns
entre 1994 et 2005 ont t collectes dans tous les villages. Les enfants
ont t regroups en trois cohortes : ceux ns dans la priode du
1er janvier 1994 au 30 avril 1997 et viss par la campagne
dimmunisation de masse au VPP-23v de 2002; ceux ns dans la priode
du 1er mai 1997 au 31 mars 2002 et ligibles au programme de
rattrapage au VPC-7; ceux ns dans la priode du 1er avril 2002 au
31 dcembre 2005 et ligibles au programme dimmunisation de routine
au VPC-7.
RSULTATS : Dans la 1re cohorte (n=896), 86,8 % (95% IC : 84,4 %-
89,0 %) ont t vaccines au VPP-23v. Dans la 2e cohorte (n=1252),
84,3 % (95% IC : 82,1 %-86,2 %) ont reu une dose de VPC-7 ou plus.
Dans la 3e cohorte, 90,4% (95% CI : 88,5 %-92,1 %) ont reu 4 doses de
VPC-7. Un retard de plus de 4 semaines dans ladministration du VPC-7 a
t observ pour 26,3 % de lensemble des doses administres. Des
variations substantielles ont t observes entre les villages pour tous les
indicateurs.
CONCLUSION : Dans la configuration complexe dune rgion nordique
et isole, les taux de couverture au VPC-7 au Nunavik sont similaires
ceux retrouvs dans les enqutes populationnelles du Qubec.
MOTS CLS : streptococcus pneumoniae; vaccins pneumococciques;
immunisation; maladies infectieuses; sant des populations autochtones