[Application of cluster randomization method on typhoid Vi vaccine trails]

OBJECTIVE

To describe the design and application of cluster randomized controlled method on typhoid Vi vaccine trial, and to assess the effect of implementation.

METHODS

Simple size calculation of cluster-randomized trial was used to determine the sample size of the two groups and a vaccination campaign was conducted. The study group was given typhoid Vi vaccine and the control group was given meningococcal A vaccine.

RESULTS

According to sample size calculation, a total sample of 96,121 participants was required and the study areas were divided into 108 clusters. In practice, 53 study clusters with 44,054 participants and 54 control clusters with 48,422 participants were stratified and matched according to size, location (urban or rural), characteristics (school, department, factory, demography) were randomized respectively. Confounding factors of two groups including age, sex, resident area, income, level of education were compared. It was found that the ratio of all confounding factors between the two groups were comparable and balanced.

CONCLUSION

Confounding factors can be better controlled between study group and the control group by applying cluster-randomized method on vaccine trail which enabled the intervention to be more scientifically evaluated; The implementation of cluster randomization trial was simple and easy to be accepted.

Rate of hepatitis B seropositivity following mass vaccination in the Islamic Republic of Iran

Universal vaccination of all neonates against hepatitis B virus has been implemented in the Islamic Republic of Iran since 1993. To evaluate the efficacy of the programme, 2 large seroepidemiologic surveys were conducted before and after mass vaccination on a representative sample of 1/1000 of the population. The overall seropositivity rate showed no significant decline between 1991 and 1999 but in the age group 2-14 years the rates reduced significantly (1.3% versus 0.8%, P < 0.05). Interestingly, we observed a significantly higher decline in hepatitis B virus carrier rate in rural (1.5% versus 0.6%) than urban areas (1.1% versus 0.9%). Universal vaccination significantly decreased the carrier rate among young children in this country.

Risque de variole, vaccination et bioterrorisme

The use of the smallpox virus as a biological weapon is very old. Confronted with a high probability of a current bioterrorist menace, counteracting strategies have been developed. One of the principle aims relies on the vaccination of teams dedicated to the management of persons infected and the stocking of vaccine for the whole population of a country. Following worldwide eradication of the disease, preventive vaccination was topped in 1978 in France for the primo-vaccination, and in 1984 for repeat vaccinations. The various strains used in the first generation vaccinations are weakened living vaccine, the natural host and origin of which is unknown. Second and third generations vaccines are under study; the principle objective is to obtain efficacy with a minimum of side effects. There are two types of adverse events, generally observed with the first generation vaccines: the first, extremely rare, can be life-threatening; the others, more frequent (10 to 15% of patients) are benign. In emergency situations, in the presence of smallpox, there should be no absolute contraindications to vaccination. In the bioterrorist context, massive vaccination campaigns of the population are unadvisable (because of the considerable risk of death and severe adverse events) in the absence of any real permit, in each case, definition of the vaccinal strategy to be adopted.

Electronic patient registration and tracking at mass vaccination clinics: a clinical study

To protect the citizens of the United States from the use of dangerous biological agents, the Center for Disease Control and Prevention (CDC) has been actively preparing to deal with the consequences of such an attack. Their plans include the deployment of mass immunization clinics to handle postevent vaccinations. As part of the planning efforts by the Western New York Public Health Alliance, a Web-based electronic patient registration and tracking system was developed and tested at a recent trial smallpox vaccination clinic. Initial goals were to determine what the pitfalls and benefits of using such a system might be in comparison to other methods of data collection. This exercise proved that use of an electronic system capable of scanning two-dimensional bar codes was superior to both paper-based and optical character recognition (OCR) methods of data collection and management. Major improvements in speed and/or accuracy were evident in all areas of the clinic, especially in patient registration, vaccine tracking and postclinic data analysis.

Intranasal vaccine for prevention of influenza in children

The current strategy for combating the yearly toll of influenza is to protect the highest-risk individuals through annual immunization. Despite its effectiveness, the inactivated influenza vaccine is underused, and no substantial decrease in influenza-related morbidity and mortality has occurred during the past two decades. Increasing recognition of (1) the high rate of influenza and the substantial morbidity it causes in otherwise healthy children and (2) the dominant role of children in community transmission of the influenza virus has led to the proposal for routine immunization of healthy children. This strategy would both reduce the medical burden of influenza in children and limit the spread of the disease. FluMist, because of its ease of administration, tolerability, and safety, is well suited for mass immunization. The success of such an immunization policy will, however, be predicated on addressing organizational and logistical challenges. Pharmacists will be key in developing the educational foundation and organizational framework for such expanded coverage.

Initial experience with mass immunization as a bioterrorism countermeasure

Anthrax vaccine was administered to approximately 5000 individuals at a deployed location near Iraq in a 1-week period. This report describes the planning and administrative process to initiate such a program, with a snapshot view of the first week of immunization. Compliance with this program was important to best protect troops in this high-threat region. The authors share their experience and detail the process of handling refusals, as these are most likely to reveal themselves at the beginning of an immunization program. The program resulted in a compliance rate of 98%. With increased terrorist threats and widespread availability of biologic agents of mass destruction, experiences with such immunization programs should be described in the literature and analyzed in anticipation of similar programs in the future.

Lessons learned: the "pale horse" bioterrorism response exercise

The city of San Antonio, Texas, and the Fort Sam Houston Army Post conducted a bioterrorism response exercise to test the command infrastructure in a large tabletop exercise. A number of local, state, and federal agencies participated in the exercise. The scenario, program format, and multiple lessons learned from this experience are described. Needs for additional services, planning, and legal issues are identified.

Parameters of control when facing stochastic demand: a DEA approach applied to Bangladeshi vaccination sites

An aim of vaccination programs is near-complete coverage. One method for achieving this is for health facilities providing these services to operate frequently and for many hours during each session. However, if vaccine vials are not fully used, the remainder is often discarded, considered as waste. Without an active appointment schedule process, there is no way for facility staff to control the stochastic demand of potential patients, and hence reduce waste. And yet reducing the hours of operation or number of sessions per week could hinder access to vaccination services. In lieu of any formal system of controlling demand, we propose to model the optimal number of hours and sessions in order to maximize outputs, the number and type of vaccines provided given inputs, using Data Envelopment Analysis (DEA). Inputs are defined as the amount of vaccine wastage and the number of full-time equivalent staff, size of the facility, number of hours of operation and the number of sessions. Outputs are defined as the number and type of vaccines aimed at children and pregnant women. This analysis requires two models: one DEA model with possible reallocations between the number of hours and the number of sessions but with the total amount of time fixed and one model without this kind of reallocation in scheduling. Comparing these two scores we can identify the "gain" that would be possible were the scheduling of hours and sessions modified while controlling for all other types of inefficiency. By modeling an output-based model, we maintain the objective of increasing coverage while assisting decision-makers determining optimal operating processes.

[Smallpox--historical or real threat]

Presently, there is no real possibility of natural re-emergence of smallpox virus, which was eradicated globally more then 25 years ago. During the last decade the possibility of use of smallpox virus as a biological weapon by a criminal organisation was emphasised. The re-emergence of smallpox virus would lead to unprecedented disaster. Theoretical models indicated that only extremely strict and enforced interventions could stop the spread of epidemic, but the assumptions of these models were unrealistic. Presently, there are limited stocks of the first generation smallpox vaccine left in the world. This vaccine, as well as the second-generation vaccine are associated with multiple adverse events, including fatalities and may not be accepted by society. Much safer vaccines are now being developed. Strategic plan of prophylactic vaccinations requires defining the groups to be immunised in the first place and whether immunisation should start before or after a first smallpox case would occur.

[Management of vaccination practices in adults: the influenza vaccination campaign in Lazio region, Italy]

This paper focuses on key issues of the organizational model of the influenza vaccination campaign in Lazio region, Italy, started during the 1999-2000 season. The following crucial features of the model are emphasized: a strong support given by Regional Health Agency; a high level of commitment of local health authorities; a considerable involvement of general practitioners; the appropriation of economical incentives related to different levels of coverage; an "ad hoc " information system. The model resulted in a remarkable increase of the number of vaccinations among elderly population (from about 420,000 in the 2000-2001 vaccination campaign to about 560,000 in the successive campaign) and of the correspondent levels of coverage (from 45.7% in the 2000-2001 vaccination campaign to 59.2% in the successive campaign). Nevertheless, further efforts should be provided to better identify population at risk, and to reach the most disadvantaged groups. Moreover, actions are to be performed to assess health and economic benefits of vaccination campaign, in order to improve the efficiency of health care planning programs.

The impact of the national polio immunization campaign on levels and equity in immunization coverage: evidence from rural North India

Few studies have investigated the impact of immunization campaigns conducted under the global polio eradication program on sustainability of polio vaccination coverage, on coverage of non-polio vaccines (administered under Expanded Program on Immunization (EPI)), and on changes in social inequities in immunization coverage. This study proposes to fill the gaps in the evidence by investigating the impact of a polio immunization campaign launched in India in 1995. The study uses a before-and-after study design using representative samples from rural areas of four North Indian states. The National Family Health Survey I (NFHS I) and NFHS II, conducted in 1992-93 and 1998-99 respectively, were used as pre- and post-intervention data. Using pooled data from both the surveys, multivariate logistic regression models with interaction terms were used to investigate the changes in social inequities. During the study period, a greater increase was observed in the coverage of first dose of polio compared to three doses of polio. Moderate improvements in at least one dose of non-polio EPI vaccinations, and no improvements in complete immunization against non-polio EPI diseases were observed. The polio campaign was successful, to some extent, in reducing gender-, caste- and wealth-based inequities, but had no impact on religion- or residence-based inequities. Social inequities in non-polio EPI vaccinations did not reduce during the study period. Significant dropouts between first and third dose of polio raise concerns of sustainability of immunization coverage under a campaign approach. Similarly, little evidence to support synergy between polio campaign and non-polio EPI vaccinations raises questions about the effects of polio campaign on routine health system's functions. However, moderate success of the polio campaign in reducing social inequities in polio coverage may offer valuable insights into the routine health systems for addressing persistent social inequities in access to health care.

CHEMICAL AND BIOLOGICAL TERRORISM PREPAREDNESS FOR STAFF DEVELOPMENT SPECIALISTS

Staff development specialists must adapt orientation and continuing/life-long learning educational programs to provide nursing staff with the knowledge and skills required to respond to a biological or chemical terrorist attack. The integration of accurate, reliable, and timely information into staff development programs will contribute to the advancement of a national nursing workforce adequately prepared to respond to a major public health event resulting from the intentional use of biological and chemical weapons.

Use of administrative data to estimate mass vaccination campaign coverage, Burkina Faso, 1999

Administrative coverage data are commonly used to assess coverage of mass vaccination campaigns. These estimates are obtained by dividing the number of doses administered by the number of children of eligible age, usually at the health district level. This study used data from a cluster survey conducted in each of the 53 Burkina Faso health districts immediately after 1999 the National Immunization Days to assess whether administrative estimates correlated with those obtained through survey and whether the former identified districts that achieved suboptimal coverage as measured by cluster survey. During the first round of the campaign there was no significant correlation between data obtained by either method. The correlation was only marginally better during the second round. Although useful to help plan the logistics of a campaign, administrative coverage data should be used with other evaluation techniques in order to determine the number of eligible children vaccinated during a mass campaign.

Implementing a seventh grade vaccination law: school factors associated with completion of required immunizations

OBJECTIVES

We investigated school factors associated with successful implementation of a seventh grade vaccination requirement.

METHODS

The proportion of students vaccinated with hepatitis B vaccine and measles containing vaccine was determined from records of schools in San Diego County, California. A school survey identified compliance strategies. Analysis identified factors associated with coverage.

RESULTS

In October 1999, 67.2% of 38,875 students had received the required vaccine doses. Of 315 schools, coverage was less than 40% in 60 schools and exceeded 80% in 111 schools. Factors associated with high coverage included private schools, early and frequent notice to parents, and, for public schools, higher overall socioeconomic status of students.

CONCLUSIONS

In preparation for a middle school vaccination requirement, early and frequent notification of parents improves coverage. Schools with a high percentage of low socioeconomic status students may require extra resources to support implementation.