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Biomedical subjects

P De Wals

Publications and source records attributed to P De Wals.

At least 19 recordsLinked to original sources
PubMed2005

An analytical framework for immunization programs in Canada.

Recent years have seen an increase in the number of new vaccines available on the Canadian market, and increasing divergence in provincial and territorial immunization programs as jurisdictions must choose among available health interventions with limited funding. We present an analytical framework, which we have developed to assist in the analysis and comparison of potential immunization programs. The framework includes 58 criteria classified into 13 categories, including the burden of disease, vaccine characteristics and immunization strategy, cost-effectiveness, acceptability, feasibility, and evaluability of program, research questions, equity, ethical, legal and political considerations. To date this framework has been utilized in a variety of different contexts, such as to structure expert presentations and reports and to examine the degree of consensus and divergence among experts, and to establish priorities. It can be transformed for a variety of other uses such as educating health professionals and the general public about immunization.

Canada↗
PubMed2001

Complications of meningococcal disease in college students.

A retrospective study was conducted to provide a description of the risk, complications, fatality, and sequelae associated with invasive meningococcal disease in college students admitted in the Allegheny county (Pennsylvania) hospital system from January 1990 to May 1999.

Adult↗
PubMed2001

Effectiveness of a mass immunization campaign against serogroup C meningococcal disease in Quebec.

CONTEXT: An outbreak of meningococcal disease in Quebec province prompted a mass immunization program. The impact of this campaign on the epidemiology of meningococcal disease has not been studied. OBJECTIVES: To study the impact of a mass immunization campaign using polysaccharide vaccine on the epidemiology of meningococcal disease (MCD) and to assess serogroup C vaccine effectiveness (VE). DESIGN, SETTING, AND SUBJECTS: Analysis of MCD cases reported in Quebec from 1990 to 1998, before and after the mass immunization campaign was conducted during the winter of 1992-1993, when 84% of residents aged 6 months to 20 years (the target population, approximately 1.9 million individuals) were vaccinated. MAIN OUTCOME MEASURES: Incidence of MCD in 1990-1998; incidence of culture-proven serogroup C MCD between April 1, 1993, and March 31, 1998, compared among vaccinated and unvaccinated persons in the target population. RESULTS: The incidence of serogroup C disease decreased after the mass immunization campaign, from 1.4 per 100 000 in 1990-1992 to 0.3 per 100 000 in 1993-1998, and the overall incidence of other serogroups remained stable at 0.7 per 100 000, with a small increase in the proportion of cases caused by serogroup Y (P =.009). Protection from serogroup C MCD was indicated in the first 2 years after vaccine administration (VE, 65%; 95% confidence interval [CI], 20%-84%), but not in the next 3 years (VE, 0%; 95% CI, -5% to 65%). Vaccine effectiveness was strongly related to age at vaccination: 83% (95% CI, 39%-96%) for ages 15 through 20 years, 75% (95% CI, - 17% to 93%) for ages 10 through 14 years, and 41% (95% CI, -106% to 79%) for ages 2 through 9 years. There was no evidence of protection in children younger than 2 years; all 8 MCD cases in this age group occurred in vaccinees. CONCLUSIONS: Serogroup C polysaccharide vaccine is effective for controlling outbreaks in teenaged individuals but should not be used in children younger than 2 years. The mass campaign did not induce significant serogroup switching.

Adolescent↗
PubMed2001

Surveillance of invasive Streptococcus pneumoniae infection in the province of Quebec, Canada, from 1996 to 1998: serotype distribution, Antimicrobial susceptibility, and clinical characteristics.

In the province of Quebec, Canada, from 1996 to 1998, 3,650 invasive Streptococcus pneumoniae infections were reported. A total of 1,354 isolates were serotyped and tested for antimicrobial susceptibility. The distribution of serotypes remained stable over the 3 years, with serotypes 14, 6B, 4, 9V, 23F, and 19F accounting for 61% of the isolates. Overall, 90% of isolates were included in the current 23-valent vaccine and 67% were included in the 7-valent conjugate vaccine. We were able to determine that resistance to penicillin and to other antibiotics is increasing.

Adolescent↗
PubMed2001

Cost-effectiveness of a lottery for increasing physicians' responses to a mail survey.

To evaluate the cost-effectiveness of a lottery on physicians' responses to a mail survey, a randomized controlled trial was conducted with a random sample of 1,000 members of the Quebec Federation of General Practitioners in 1997. For the first mailing of this survey, each respondent was randomly assigned to the control or experimental group, which was offered participation in a lottery upon return of the questionnaire. Response rate was 41.2% in the experimental group and 34.8% in the control group, a 6.4% difference (CI95%: 0.6%-12.6%). The additional cost of the lottery was about Can$500, giving an incremental cost of Can$16 per questionnaire returned. In conclusion, a lottery resulted in a small but statistically significant increase in the response rate of physicians to a mail survey. This method may be a cost-effective option when applied to large surveys.

Cost-Benefit Analysis↗
PubMed2001

Vaccination practices of Quebec family physicians. Influenza vaccination status and professional practices for influenza vaccination.

OBJECTIVE: To assess influenza vaccination status and influenza vaccination practices of family physicians in Quebec. DESIGN: Mail survey of a random sample of 1000 family physicians. SETTING: Family practices in the province of Quebec. PARTICIPANTS: Of 1000 Quebec family physicians sent questionnaires, 550 responded. After excluding physicians who worked only in institutions, had no patients older than 65 years, or did clinical work less than 20% of the time, 379 respondents were eligible for the study. MAIN OUTCOME MEASURES: Vaccination status of family physicians in 1996 and professional practices based on six clinical and administrative activities pertaining to influenza vaccination. RESULTS: Prevalence of vaccination was 35.5% (95% confidence interval 30.8% to 40.4%) among responding physicians and was higher among those 60 years and older, those with a chronic condition, and those perceiving high peer pressure to get vaccinated. Most respondents frequently assessed the current influenza vaccination status of their patients, risk factors for influenza-related complications, and contraindications to the vaccine. They also frequently provided education about influenza and its vaccine, recommended vaccination, and administered the vaccine. Only a few reported assessing prior influenza vaccinations or recording vaccination status regularly. Finally, vaccinated physicians recommended the vaccine more frequently to their patients than unvaccinated physicians did. CONCLUSION: Promotion programs focusing on peer influence could increase vaccination of family physicians. This could in turn improve vaccination coverage of elderly patients.

Aged↗
PubMed2000

Comparative immunogenicity under field conditions of two recombinant hepatitis B vaccines in 8-10-year-old children.

The immunogenicity of two hepatitis B vaccines was compared in 8-10-year-old children immunized in a school program. One year apart, 1129 children received Engerix-B 10 microg vaccine (EB), and 1126 received Recombivax-HB 2.5 microg (RB), following the 0, 1, 6 schedule. Blood samples were collected one month after the third dose. Anti-Hbs were measured by commercial radioimmunoassay. In the EB group, 99.1% of the children seroconverted (>/=2 IU/l) compared to 99.7% in the RHB group (p=0.09). The seroprotection rate (>/=10 IU/l) was similar for both groups: 98.9% in the EB group and 99.2% in the RB group (p=0.66). However, GMCs of anti-HBs were higher in children given EB compared to those given RB (7307 vs. 3800 mIU/ml, p<0.0001). This study showed that both vaccines were highly immunogenic, in the course of a regular field immunization program. However, the difference observed in the antibody levels attained according to the vaccine may play a role in the long-term protection of these children.

Child↗
PubMed1999

Quality of care in unlicensed homes for the aged in the eastern townships of Quebec.

BACKGROUND: The recent proliferation of unlicensed homes for the aged in Quebec, coupled with the increased needs of the population they serve, has raised concerns about the quality of case these homes provide. The authors compared the quality of care in unlicensed homes with that in licensed long-term care facilities in a region of Quebec. METHODS: The study involved 301 impaired people aged 65 and over in 88 residential care facilities (52 unlicensed, 36 licensed) in the Eastern Townships of Quebec. Study participants were chosen according to a 2-stage sampling scheme: stratified sampling of the primary units (facilities) and random sampling of the secondary units (residents). Quality of care was measured using the QUALCARE scale, a multidimensional instrument that uses a 5-point scale to assess 6 dimensions of care: environmental, physical, medical management, psychosocial, human rights and financial. A mean score of more than 2 was considered indicative of inadequate care. RESULTS: Overall, the quality of care was similar in the unlicensed and licensed facilities (mean global score 1.61 [standard error of the mean (SEM) 0.06] and 1.47 [SEM 0.09] respectively). Examination of dimension-specific quality-of-care scores revealed that the unlicensed homes performed worse than the licensed facilities in 2 areas of care: physical care (mean score 1.80 [SEM 0.08] v. 1.51 [SEM 0.09] respectively, p = 0.017) and medical management (1.37 [SEM 0.06] v. 1.14 [SEM 0.05], p = 0.004). The dimension-specific scores also revealed that both types of homes lacked appropriate attention to the psychosocial aspect of care. Overall, 25% of the facilities provided inadequate care to at least one resident. This situation was especially prevalent among homes with fewer than 40 residents, where up to 20% of the residents received inadequate care. INTERPRETATION: Most of the unlicensed homes for the aged that were studied delivered care of relatively good quality. However, some clearly provided inadequate care.

Aged↗
PubMed1999

A method for the follow-up of clusters of adverse reproductive outcomes.

Clusters of adverse reproductive outcomes are reported with increasing frequency to public health authorities. Most are random events and only a very small proportion is likely due to identifiable environmental agents. Often, a preliminary study confirms the existence of a spatial and temporal excess but no biologically plausible cause is found. These cases require a follow-up of incidence to identify any continuing excess. A conceptually simple 'fixed window' technique of follow up is proposed. The power of the test is mainly influenced by the magnitude of the increase in rate, the number of adverse outcomes selected for observation and the acceptable false alarm rate. This technique has several advantages compared with other currently used methods. From a public health point of view, two important factors are to be considered in setting the parameters of the test: the delay in providing an answer for the community and the availability of resources for conducting environmental investigations.

Bias↗
PubMed1999

Investigation of clusters of adverse reproductive outcomes, an overview.

Clusters of adverse reproductive outcomes are reported with increasing frequency to public health services, but it is likely that only a minority of clusters are caused by a common environmental teratogen or mutagen. Many guidelines and protocols have been developed for the investigation and the management of chronic disease clusters and can be applied to the study of adverse reproductive outcomes. Cluster investigation normally follows four successive phases: (i) the generation of one or more etiologic hypotheses, (ii) the confirmation of the hypotheses, (iii) an intervention aimed at reducing any dangerous exposure, and (iv) the evaluation of the effect of the intervention. However, each situation is unique and there is no standard recipe for conducting the epidemiologic investigation at each successive phase, for choosing the appropriate statistical technique and for communicating with interested parties. In order to minimize both the risk of pursuing a worthless investigation and the risk of ignoring a real excess of cases caused by an adverse environmental factor, it is imperative to rely on a team of specialists with expertise in epidemiology, statistics, toxicology, embryology, and communication.

Clinical Protocols↗
PubMed1999

Correlates of care quality in long-term care facilities: a multilevel analysis.

Hierarchical modeling was employed to explore correlates of the quality of care provided in long-term care facilities. For this purpose, a multilevel analysis offers two advantages over traditional analytical approaches. First, it accounts for the correlated nature of data recorded on multiple residents from the same facility. Second, it enables the investigators to study the influence of both resident and facility characteristics on care quality. The analysis was performed on data from 301 residents randomly sampled from 88 facilities located in the Province of Quebec, Canada. Results revealed that the presence of cognitive deficits was the strongest correlate of the quality of care provided to a resident. However, this relationship was found to vary significantly across facilities. Four facility-level variables were found to influence the relationship between cognitive functioning and care quality: the number of external collaborators the facility has, the type of training the facility manager has, the size of the facility, and the age distribution of its clientele. From these results, we suggest means to improve the quality of care provided to cognitively impaired older adults living in long-term care facilities.

Administrative Personnel↗
PubMed1998

Complications and sequelae of meningococcal disease in Quebec, Canada, 1990-1994.

To study complications and sequelae of serogroup B and C meningococcal disease, a retrospective survey examined the outcome of all culture-proven cases reported in the province of Quebec, Canada, from January 1990 through December 1994 (serogroup B, 167 cases; serogroup C, 304 cases). Data were collected from medical files, postal questionnaires, and telephone interviews. Age groups having the most cases were the 10-19-year age group for serogroup C and the < 1-year age group for serogroup B. Fatality rates were 7% for serogroup B and 14% for serogroup C disease. Only 3% of survivors of serogroup B disease had physical sequelae, compared with 15% of survivors of serogroup C disease (skin scars, 12%; amputations, 5%; hearing loss, 2%; renal problems, 1%; and other sequelae, 4%). These results confirm the gravity of disease caused by serogroup C, serotype 2a Neisseria meningitidis and justify liberal use of vaccination for outbreak control.

Adolescent↗