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Walter A Orenstein

Publications and source records attributed to Walter A Orenstein.

At least 19 recordsLinked to original sources
PubMed2026

Do vaccinated cases transmit measles? A systematic review and meta-analysis.

INTRODUCTION: We reviewed evidence on whether vaccinated individuals can transmit measles and conducted a meta-analysis to understand transmission characteristics. METHODS: We searched and extracted data from peer-reviewed and gray literature and included studies reporting measles transmission events from vaccinated individuals. We meta-analyzed the data to calculate the median number of transmissions from vaccinated cases by measles burden, number of doses, and time since first and last dose. RESULTS: We identified 11,911 peer-reviewed and 22 gray literature records and included 33 articles in our review. Seventy individuals who had received 1 or more doses of measles-containing vaccine transmitted measles virus, resulting in 237 secondary cases. Vaccinated transmitters in eliminated areas were older (median age of 19 years (IQR: 3, 21)) than those in non-eliminated areas (median age 16 years; IQR 13, 18) (p = 0.12). Additionally, 91% (30/33) of studies provided data on subsequent transmission generations, leading to 812 measles cases traced back to vaccinated individuals, with a median of 4 (IQR: 1, 10) cases per vaccinated transmitter. CONCLUSION: Measles transmissions from vaccinated cases, although relatively uncommon, must be considered in public health investigations, as such transmissions can contribute to outbreaks.

Adolescent↗
PubMed2006

Interdisciplinary epidemiologic and economic research needed to support a universal childhood influenza vaccination policy.

Recent research indicates that influenza vaccination of children may decrease the influenza disease burden in adults to a greater extent than targeting vaccination to populations at high risk of serious disease. Possible new policies reflecting these results would add groups most likely to transmit disease to existing vaccination recommendations. Interdisciplinary research combining epidemiology with economics is needed to answer critical questions about the desirability and feasibility of potential new policies, such as what additional resources medical providers might need to expand vaccination to larger groups or what opportunity costs parents might incur in vaccinating their children annually. In this paper, the authors provide background for some of the changes in influenza vaccination rates and disease and discuss existing information gaps and research methods capable of closing these gaps. They provide several examples of interdisciplinary studies that have incorporated both economics and epidemiology or health policy issues. These studies are representative of a variety of stakeholder perspectives needed to determine whether community-based, universal childhood vaccination policies would be more efficacious and cost-effective than strategies targeted toward persons at high risk of disease complications.

Child↗
PubMed2006

Vaccine supply problems: a perspective of the Centers for Disease Control and Prevention.

Although immunization is one of the great public health achievements, continued success depends on an available supply of the vaccines that are recommended for routine use. Beginning in 2000, the United States experienced vaccine supply disruptions of unprecedented scope and magnitude. Although most of the supply disruptions have been resolved, it appears that a fragile vaccine supply will be part of the immunization environment in the United States for the foreseeable future. Here, we describe the perspective of the Centers for Disease Control and Prevention on the recent supply disruptions and the methods used to manage vaccine shortages. The present article focuses on routine pediatric vaccines, including influenza virus vaccine.

Centers for Disease Control and Prevention, U.S.↗
PubMed2006

The role of measles elimination in development of a national immunization program.

The U.S. Immunization Program has been one of the most successful efforts in preventive medicine. Since its beginning with passage of the Vaccination Assistance Act in 1962, polio, measles and rubella have been eliminated and many other vaccine-preventable diseases are at record or near record lows. In 1966, 3 years after licensure of the first measles vaccines, the Centers for Disease Control and Prevention began an effort to eliminate measles within the United States, an on-and-off effort that was to last more than 30 years. With measles elimination as the primary driver, fundamental components of today's immunization program were built that affected not only measles, but all of the vaccines and vaccine-preventable diseases of childhood. Some of the major contributions were the enactment and enforcement of immunization requirements for school attendance in all 50 states, enactment of an entitlement program for vaccine purchase, the Vaccines for Children Program, support for health services research to determine reasons for nonimmunization and interventions to improve coverage, development of standards for immunization practices and the measurement system for immunization coverage in all 50 states and 28 major urban areas. Key lessons have been: (1) the program must rest on a sound base of vaccine science and health services science; (2) having a limited number of measurable goals allows program focus, but consider strategies that have crosscutting impact; (3) accountability is critical to program performance at all levels-state, local and individual practice; and (4) establishing and maintaining political support is essential.

Adolescent↗
PubMed2006

Vaccine shortages: history, impact, and prospects for the future.

Vaccine shortages can result from higher-than-expected demand, interruptions in production/supply, or a lack of resources to purchase vaccines. Each of these factors has played a role in vaccine shortages in the United States during the past 20 years. Since 2000, the United States has experienced an unprecedented series of shortages of vaccines recommended for widespread use against 9 diseases, after more than 15 years without vaccine supply problems. In developing countries, the major cause of vaccine shortages is lack of resources to purchase them. Although there are several steps that could reduce the likelihood of future vaccine shortages, many would take several years to implement. Consequently, we will probably continue to see occasional shortages of vaccines in the United States in the next few years.

Communicable Disease Control↗
PubMed2004

Vaccine policy changes and epidemiology of poliomyelitis in the United States.

CONTEXT: The last case of poliomyelitis in the United States due to indigenously acquired wild poliovirus occurred in 1979; however, as a consequence of oral poliovirus vaccine (OPV) use that began in 1961, an average of 9 cases of vaccine-associated paralytic poliomyelitis (VAPP) were confirmed each year from 1961 through 1989. To reduce the VAPP burden, national vaccination policy changed in 1997 from reliance on OPV to options for a sequential schedule of inactivated poliovirus vaccine (IPV) followed by OPV. In 2000, an exclusive IPV schedule was adopted. OBJECTIVE: To review the epidemiology of paralytic poliomyelitis and document the association between the vaccine schedule changes and VAPP in the United States. DESIGN AND SETTING: Review of national surveillance data from 1990 through 2003 for cases of confirmed paralytic poliomyelitis. MAIN OUTCOME MEASURES: Number of confirmed paralytic poliomyelitis cases, including VAPP, and ratio of VAPP cases to number of doses of OPV distributed that occurred before, during, and after implementation of policy changes. RESULTS: From 1990 through 1999, 61 cases of paralytic poliomyelitis were reported; 59 (97%) of these were VAPP (1 case per 2.9 million OPV doses distributed), 1 case was imported, and 1 case was indeterminate. Thirteen cases occurred during the 1997-1999 transitional policy period and were associated with the all-OPV schedule; none occurred with the IPV-OPV schedule. No cases occurred after the United States implemented the all-IPV policy in 2000. The last imported poliomyelitis case occurred in 1993 and the last case of VAPP occurred in 1999. CONCLUSION: The change in polio vaccination policy from OPV to exclusive use of IPV was successfully implemented; this change led to the elimination of VAPP in the United States.

Health Policy↗
PubMed2004

Evolution of measles elimination strategies in the United States.

There have been 3 efforts to eliminate measles from the United States since the introduction of measles vaccine in 1963. To date, 10 major lessons have been learned from elimination efforts. First, elimination requires very high vaccination-coverage levels by age 2 years. Second, school immunization requirements ensure high coverage rates among schoolchildren. Third, a second dose of measles vaccine is needed to achieve satisfactory levels of immunity. Fourth, school immunization requirements can also ensure delivery of a second dose. Fifth, coverage assessment is crucial. Sixth, measles surveillance is critical for developing, evaluating, and refining elimination strategies. Seventh, surveillance requires laboratory backup to confirm a diagnosis. Eighth, tracking measles virus genotypes is critical to determining if an endemic strain is circulating. Ninth, once endemic transmission has been interrupted, internationally imported measles cases will continue and will cause small outbreaks. Tenth, collaborative efforts with other countries are essential to reduce imported measles cases.

Adolescent↗
PubMed2004

Evaluation of the measles clinical case definition.

An accurate system of identifying and classifying suspected measles cases is critical for the measles surveillance system in the United States. To examine the performance of the clinical case definition in predicting laboratory confirmation of suspected cases of measles, we reviewed 4 studies conducted between 1981 and 1994. A clinical case definition was examined that included a generalized maculopapular rash, fever (>or=38.3 degrees C, if measured), and either a cough, coryza, or conjunctivitis. Serological confirmation of measles was done either by hemagglutination inhibition assay, complement fixation assay, or enzyme immunoassays. The positive predictive value of the clinical case definition decreased from 74% to 1% as incidence decreased from 171 cases/100000 population to 1.3 cases/100000 population. Sensitivity was high, and for the larger studies with the most precise estimates, sensitivity was 76%-88%. The low positive predictive value of the clinical case definition in settings of low incidence demonstrates that serological confirmation is essential to ensure an accurate diagnosis of measles when measles is rare.

Adolescent↗
PubMed2004

Defining and assessing measles elimination goals.

Although 3 of 6 World Health Organization regions have established measles elimination targets, measles elimination goals are not well defined. In general, disease elimination has been defined as the reduction of incidence in a population to zero. However, measles is so contagious that zero incidence is difficult to achieve and sustain because the risk of imported measles remains while measles is endemic in any country. Also, imported cases will occasionally result in short chains of indigenous transmission unless a country achieves 100% immunity. Therefore, the United States currently uses the absence of endemic measles (i.e., no indigenous chains of transmission persisting for >or=1 year) as the programmatic goal for measles elimination. To document the absence of endemic measles in the United States, we compiled information on the epidemiology of measles, genotype distribution, population immunity, and adequacy of measles surveillance. A panel of experts, convened in March 2000 to review the data, concluded that measles is no longer endemic in the United States.

Disease Notification↗
PubMed2004

Financing immunizations in the United States.

Children in the United States receive immunizations through both private and public sectors. The federal government has supported childhood immunization since 1963 through the Vaccination Assistance Act (Section 317 of the Public Health Service Act). Since 1994, the Vaccines for Children (VFC) program has provided additional support for childhood vaccines. In 2002, 41% of childhood vaccines were purchased through VFC, 11% through Section 317, 5% through state and/or local governments, and 43% through the private sector. The recent introduction of more-expensive vaccines, such as pneumococcal conjugate vaccine, has highlighted weaknesses in the current system. Adult immunization is primarily performed in the private sector. Until 1981, there was no federal support for adult immunization. Since 1981, Medicare has reimbursed the cost of pneumococcal vaccine for its beneficiaries; influenza vaccine was added in 1993. This paper summarizes the history of financing immunizations in the United States and discusses some current problems and proposed solutions.

Adult↗
PubMed2004

Measles vaccines and the potential for worldwide eradication of measles.

The annual number of reported measles cases in the United States has declined from between 3 million and 4 million in the prevaccine era to <100 cases in association with the highest recorded immunization rates in history. Because of continued importation of measles into the United States, young children who are not vaccinated appropriately may experience more than a 60-fold increase in risk of disease. Unsubstantiated claims suggesting an association between measles vaccine and neurologic disorders have led to reduced vaccine use and a resurgence of measles in countries where immunization rates have declined below the level needed to maintain herd immunity. To address the possibility of worldwide control of measles, efforts to ensure high immunization rates among people in both developed and developing countries must be sustained.

Autistic Disorder↗
PubMed2002

Development of pediatric vaccine recommendations and policies.

A significant decrease in each vaccine-preventable disease has occurred since the introduction of the respective immunizations now included in the recommended childhood immunization schedule. The process through which a vaccine must travel from development to approval and implementation is complex. Hurdles include receiving approval from several advisory committees, government agencies, and professional organizations. At each step in the process, data regarding safety, immunogenicity, and efficacy are evaluated continuously and rigorously. Once a vaccine is approved by the Food and Drug Administration (FDA) and incorporated into the recommended childhood immunization schedule, continuing issues include those that deal with supply, safety, effectiveness, and financing. The logistics of development and implementation of pediatric vaccine recommendations and policies are reviewed.

Advisory Committees↗