Vance Dietz

Too little but not too late: Results of a literature review to improve routine immunization programs in developing countries

BackgroundGlobally, immunization services have been the center of renewed interest with increased funding to improve services, acceleration of the introduction of new vaccines, and the development of a health systems approach to improve vaccine delivery. Much of the credit for the increased attention is due to the work of the GAVI Alliance and to new funding streams. If routine immunization programs are to take full advantage of the newly available resources, managers need to understand the range of proven strategies and approaches to deliver vaccines to reduce the incidence of diseases. In this paper, we present strategies that may be used at the sub-national level to improve routine immunization programs.MethodsWe conducted a systematic review of studies and projects reported in the published and gray literature. Each paper that met our inclusion criteria was rated based on methodological rigor and data were systematically abstracted. Routine-immunization – specific papers with a methodological rigor rating of greater than 60% and with conclusive results were reported.ResultsGreater than 11,000 papers were identified, of which 60 met our inclusion criteria and 25 papers were reported. Papers were grouped into four strategy approaches: bringing immunizations closer to communities (n = 11), using information dissemination to increase demand for vaccination (n = 3), changing practices in fixed sites (n = 4), and using innovative management practices (n = 7).ConclusionImmunization programs are at a historical crossroads in terms of developing new funding streams, introducing new vaccines, and responding to the global interest in the health systems approach to improving immunization delivery. However, to complement this, actual service delivery needs to be strengthened and program managers must be aware of proven strategies. Much was learned from the 25 papers, such as the use of non-health workers to provide numerous services at the community level. However it was startling to see how few papers were identified and in particular how few were of strong scientific quality. Further well-designed and well-conducted scientific research is warranted. Proposed areas of additional research include integration of additional services with immunization delivery, collaboration of immunization programs with new partners, best approaches to new vaccine introduction, and how to improve service delivery.

Validity of vaccination cards and parental recall to estimate vaccination coverage: A systematic review of the literature

Immunization programs frequently rely on household vaccination cards, parental recall, or both to calculate vaccination coverage. This information is used at both the global and national level for planning and allocating performance-based funds. However, the validity of household-derived coverage sources has not yet been widely assessed or discussed. To advance knowledge on the validity of different sources of immunization coverage, we undertook a global review of literature. We assessed concordance, sensitivity, specificity, positive and negative predictive value, and coverage percentage point difference when subtracting household vaccination source from a medical provider source. Median coverage difference per paper ranged from -61 to +1 percentage points between card versus provider sources and -58 to +45 percentage points between recall versus provider source. When card and recall sources were combined, median coverage difference ranged from -40 to +56 percentage points. Overall, concordance, sensitivity, specificity, positive and negative predictive value showed poor agreement, providing evidence that household vaccination information may not be reliable, and should be interpreted with care. While only 5 papers (11%) included in this review were from low-middle income countries, low-middle income countries often rely more heavily on household vaccination information for decision making. Recommended actions include strengthening quality of child-level data and increasing investments to improve vaccination card availability and card marking. There is also an urgent need for additional validation studies of vaccine coverage in low and middle income countries.

Experiences Integrating Delivery of Maternal and Child Health Services With Childhood Immunization Programs: Systematic Review Update

BACKGROUND The World Health Organization and the United Nations Childrens Fund promote integration of maternal and child health (MCH) and immunization services as a strategy to strengthen immunization programs. We updated our previous review of integrated programs and reviewed reports of integration of MCH services with immunization programs at the service delivery level. METHODS Published and unpublished reports of interventions integrating MCH and immunization service delivery were reviewed by searching journal databases and Web sites and by contacting organizations. RESULTS Among 27 integrated activities, interventions included hearing screening, human immunodeficiency virus services, vitamin A supplementation, deworming tablet administration, malaria treatment, bednet distribution, family planning, growth monitoring, and health education. When reported, linked intervention coverage increased, though not to the level of the corresponding immunization coverage in all cases. Logistical difficulties, time-intensive interventions ill suited for campaign delivery, concern for harming existing services, inadequate overlap of target age groups, and low immunization coverage were identified as challenges. CONCLUSIONS Results of this review reinforce our 2005 review findings, including importance of intervention compatibility and focus on immunization program strength. Ensuring proper planning and awareness of compatibility of service delivery requirements were found to be important. The review revealed gaps in information about costs, comparison to vertical delivery, and impact on all integrated interventions that future studies should aim to address.

Survey of obstetrician-gynecologists in the United States about toxoplasmosis

Background: Although the incidence of toxoplasmosis is low in the United States, up to 6000 congenital cases occur annually. In September 1998, the Centers for Disease Control and Prevention held a conference about toxoplasmosis; participants recommended a survey of the toxoplasmosis-related knowledge and practices of obstetrician-gynecologists and the development of professional educational materials for them. Methods: In the fall of 1999, surveys were mailed to a 2% random sample of American College of Obstetricians and Gynecologists (ACOG) members and to a demographically representative group of ACOGmembers known as the Collaborative Ambulatory Research Network (CARN). Responses were not significantly different for the random and CARN groups for most questions (p value shown when different). Results: Among 768 US practicing ACOG members surveyed, 364 (47%) responded. Seven per cent (CARN 10%, random 5%) had diagnosed one or more case(s) of acute toxoplasmosis in the past year. Respondents were well-informed about how to prevent toxoplasmosis. However, only 12% (CARN 11%, random 12%) indicated that a positive Toxoplasma IgM test might be a false–positive result, and only 11% (CARN 14%, random 9%) were aware that the Food and Drug Administration sent an advisory to all ACOG members in 1997 stating that some Toxoplasma IgM test kits have high false–positive rates. Most of those surveyed (CARN 70%, random 59%; X2 p < 0.05) were opposed to universal screening of pregnant women. Conclusions: Many US obstetrician-gynecologists will encounter acute toxoplasmosis during their careers, but they are frequently uncertain about interpretation of the laboratory tests for the disease. Most would not recommend universal screening of pregnant women.

Monitoring Measles Eradication in the Region of the Americas: Critical Activities and Tools

The purpose of this paper is to discuss methods recommended and used by the Pan American Health Organization (PAHO) to monitor the interruption of indigenous measles transmission in the Region of the Americas. The methods used include house-to-house monitoring of vaccination coverage as a supervisory tool during both campaigns and routine vaccination; thoroughly investigating all measles outbreaks; performing routine surveillance, including weekly reporting from at least 80% of reporting units; and validating routine surveillance through active-case searches at health care institutions and schools and in the community. The strategies described have helped PAHO to increase the authority and accountability of vaccine program managers at the local, provincial, and national levels. Their efforts have permitted the Region of the Americas to reduce to three the number of countries with indigenous measles transmission and to reach a record low of 503 measles cases in 2001.

The development of global vaccine stockpiles

Global vaccine stockpiles, in which vaccines are reserved for use when needed for emergencies or supply shortages, have effectively provided countries with the capacity for rapid response to emergency situations, such as outbreaks of yellow fever and meningococcal meningitis. The high cost and insufficient supply of many vaccines, including oral cholera vaccine and pandemic influenza vaccine, have prompted discussion on expansion of the use of vaccine stockpiles to address a wider range of emerging and re-emerging diseases. However, the decision to establish and maintain a vaccine stockpile is complex and must take account of disease and vaccine characteristics, stockpile management, funding, and ethical concerns, such as equity. Past experience with global vaccine stockpiles provide valuable information about the processes for their establishment and maintenance. In this Review we explored existing literature and stockpile data to discuss the lessons learned and to inform the development of future vaccine stockpiles.

Implementation and evaluation of the Reaching Every District (RED) strategy in Assam, India, 2005–2008☆

In 2005, UNICEF and the Centers for Disease Control and Prevention implemented and evaluated the Reaching Every District (RED) approach, an intervention designed to improve key components of immunization services including planning, outreach, community mobilization, supervision, and monitoring, in select districts of Assam, India. Two intervention and 3 comparison districts were selected for a 2-year evaluation trial. In intervention districts, immunization staff received comprehensive training and ongoing supervision by a fulltime consultant, and regular monitoring of progress was conducted. Population-based vaccination coverage surveys were conducted at baseline and 2 years after the start of implementation in the 5 districts. Post-intervention process indicators were systematically collected and focus group discussions were held. At follow-up, children in both the intervention and comparison districts were twice as likely to be fully vaccinated as they were at baseline. However, sites that received intervention training were better performing than those that did not, as measured by process indicators, including a higher number of outreach visits planned and held (p=0.02), having a monitoring chart (p<0.01), and correctly calculating dropout (p<0.01). The number of supervisory visits was significantly and positively associated with other key process indicators. Although coverage did not differ significantly between intervention and comparison districts, among individual districts, process data indicate significant improvements in program quality in the intervention districts. Further studies are needed to determine if the improved process indicators have sustainable impact on maintaining improvements in coverage.

Evaluation of failure to follow vaccination recommendations as a marker for failure to follow other health recommendations

OBJECTIVE To determine whether families who fail to vaccinate their children also fail to follow other health recommendations. SETTING US civilian noninstitutionalized population. DESIGN National survey with a stratified cluster design. PARTICIPANTS Adult respondents for children 19 to 35 months of age surveyed in the 1991 National Health Interview Survey with documented vaccination history. MEASUREMENTS Comparison of responses to 23 questions related to health behaviors between respondents of up-to-date (UTD), i.e. having received 4 doses of diphtheria and tetanus toxoids and pertussis vaccine, 3 doses of polio vaccine and one measles vaccine, and non-UTD children. RESULTS Of the 781 studied children, non-UTD (n = 357) and UTD (n = 424) children, or their respondents, did not differ in 18 of the 23 studied health behaviors. However, although non-UTD and UTD children were equally likely to have car seats, non-UTD children were less likely to use them always (84.3% vs. 92.9%, P = 0.002). National Health Interview Survey respondents of non-UTD children were more likely than their counterparts never to read food labels for ingredients (28.9% vs. 20.5%, P = 0.04) or for fat/cholesterol content (33.6% vs. 22.3%, P = 0.02) and never to buy low salt foods (37.5% vs. 21.5%, P = 0.001). Multivariate analyses showed that parental education level, not a childs vaccination status, was associated with compliance with the studied health behaviors. CONCLUSION Failure to vaccinate children on time is not consistently related to the likelihood of family members following of other health recommendations. However, these data suggest that although mediated via parental educational levels, a childs immunization status helps to define families at risk for poor nutrition-related behaviors and those who are in need of counseling on seat belt use.

Issues and considerations in the use of serologic biomarkers for classifying vaccination history in household surveys

Accurate estimates of vaccination coverage are crucial for assessing routine immunization program performance. Community based household surveys are frequently used to assess coverage within a country. In household surveys to assess routine immunization coverage, a childs vaccination history is classified on the basis of observation of the immunization card, parental recall of receipt of vaccination, or both; each of these methods has been shown to commonly be inaccurate. The use of serologic data as a biomarker of vaccination history is a potential additional approach to improve accuracy in classifying vaccination history. However, potential challenges, including the accuracy of serologic methods in classifying vaccination history, varying vaccine types and dosing schedules, and logistical and financial implications must be considered. We provide historic and scientific context for the potential use of serologic data to assess vaccination history and discuss in detail key areas of importance for consideration in the context of using serologic data for classifying vaccination history in household surveys. Further studies are needed to directly evaluate the performance of serologic data compared with use of immunization cards or parental recall for classification of vaccination history in household surveys, as well assess the impact of age at the time of sample collection on serologic titers, the predictive value of serology to identify a fully vaccinated child for multi-dose vaccines, and the cost impact and logistical issues on outcomes associated with different types of biological samples for serologic testing.

Measles Elimination in the Americas: A Comparison Between Countries With a One-Dose and Two-Dose Routine Vaccination Schedule

BACKGROUND The Region of the Americas eliminated measles in 2002 through high first-dose routine measles vaccine coverage and vaccination campaigns every 4-6 years; a second routine dose at school entry was added in some countries. The impact of this second routine dose on measles elimination was evaluated. METHODS Data on socioeconomic factors, demographic characteristics, vaccination coverage, and the estimated proportion of children (<15 years of age) susceptible to measles were compiled. Countries were grouped using propensity score methods, and Kaplan-Meier curves were used to compare time to measles elimination between countries with a 1-dose schedule and those with a 2-dose schedule. RESULTS One-dose (n = 14) and 2-dose (n = 7) countries did not differ with respect to median routine first-dose measles vaccine coverage, median coverage for 3 measles campaigns, or estimated percentage of susceptible children after routine first vaccination dose and campaigns. Compared with 1-dose countries, 2-dose countries had higher median gross national income per capita (P = .002), percentage of population living in urban areas (P = .04), and female literacy (P = .01), as well as lower infant mortality (P = .007); however, no differences in time to elimination were found. CONCLUSIONS One-dose and 2-dose countries had similar times to measles elimination despite socioeconomic differences between their populations. A second routine dose might not have hastened measles elimination, because threshold immunity needed to eliminate measles was achieved with high first routine dose coverage and vaccination campaigns. Further research will be needed to determine the applicability of these findings to other regions.