Measles in developing countries.
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Anti-Bacterial Agents↗
Biomedical subjects
Neal A Halsey
Publications and source records attributed to Neal A Halsey.
Nonmedical exemptions to school immunization requirements: secular trends and association of state policies with pertussis incidence.
CONTEXT: School immunization requirements have played a major role in controlling vaccine-preventable diseases in the United States. Most states offer nonmedical exemptions to school requirements (religious or personal belief). Exemptors are at increased risk of acquiring and transmitting disease. The role of exemption policies may be especially important for pertussis, which is endemic in the United States. OBJECTIVE: To determine if (1) the rates of nonmedical exemptions differ and have been increasing in states that offer only religious vs personal belief exemptions; (2) the rates of nonmedical exemptions differ and have been increasing in states that have easy vs medium and easy vs difficult processes for obtaining exemptions; and (3) pertussis incidence is associated with policies of granting personal belief exemptions, ease of obtaining exemptions, and acceptance of parental signature as sufficient proof of compliance with school immunization requirements. DESIGN, SETTING, AND PARTICIPANTS: We analyzed 1991 through 2004 state-level rates of nonmedical exemptions at school entry and 1986 through 2004 pertussis incidence data for individuals aged 18 years or younger. MAIN OUTCOME MEASURES: State-level exemption rates and pertussis incidence. RESULTS: From 2001 through 2004, states that permitted personal belief exemptions had higher nonmedical exemption rates than states that offered only religious exemptions, and states that easily granted exemptions had higher nonmedical exemption rates in 2002 through 2003 compared with states with medium and difficult exemption processes. The mean exemption rate increased an average of 6% per year, from 0.99% in 1991 to 2.54% in 2004, among states that offered personal belief exemptions. In states that easily granted exemptions, the rate increased 5% per year, from 1.26% in 1991 to 2.51% in 2004. No statistically significant change was seen in states that offered only religious exemptions or that had medium and difficult exemption processes. In multivariate analyses adjusting for demographics, easier granting of exemptions (incidence rate ratio = 1.53; 95% confidence interval, 1.10-2.14) and availability of personal belief exemptions (incidence rate ratio = 1.48; 95% confidence interval, 1.03-2.13) were associated with increased pertussis incidence. CONCLUSIONS: Permitting personal belief exemptions and easily granting exemptions are associated with higher and increasing nonmedical US exemption rates. State policies granting personal belief exemptions and states that easily grant exemptions are associated with increased pertussis incidence. States should examine their exemption policies to ensure control of pertussis and other vaccine-preventable diseases.
Adolescent↗
Support for immunization registries among parents of vaccinated and unvaccinated school-aged children: a case control study.
BACKGROUND: Immunizations have reduced childhood vaccine preventable disease incidence by 98-100%. Continued vaccine preventable disease control depends on high immunization coverage. Immunization registries help ensure high coverage by recording childhood immunizations administered, generating reminders when immunizations are due, calculating immunization coverage and identifying pockets needing immunization services, and improving vaccine safety by reducing over-immunization and providing data for post-licensure vaccine safety studies. Despite substantial resources directed towards registry development in the U.S., only 48% of children were enrolled in a registry in 2004. Parental attitudes likely impact child participation. Consequently, the purpose of this study was to assess the attitudes of parents of vaccinated and unvaccinated school-aged children regarding: support for immunization registries; laws authorizing registries and mandating provider reporting; opt-in versus opt-out registry participation; and financial worth and responsibility of registry development and implementation. METHODS: A case control study of parents of 815 children exempt from school vaccination requirements and 1630 fully vaccinated children was conducted. Children were recruited from 112 elementary schools in Colorado, Massachusetts, Missouri, and Washington. Surveys administered to the parents, asked about views on registries and perceived utility and safety of vaccines. Parental views were summarized and logistic regression models compared differences between parents of exempt and vaccinated children. RESULTS: Surveys were completed by 56.1% of respondents. Fewer than 10% of parents were aware of immunization registries in their communities. Among parents aware of registries, exempt children were more likely to be enrolled (65.0%) than vaccinated children (26.5%) (p value = 0.01). A substantial proportion of parents of exempt children support immunization registries, particularly if registries offer choice for participation. Few parents of vaccinated (6.8%) and exempt children (6.7%) were aware of laws authorizing immunization registries. Support for laws authorizing registries and requiring health care providers to report to registries was more common among parents of vaccinated than exempt children. Most parents believed that the government, vaccine companies or insurance companies should pay for registries. CONCLUSION: Parental support for registries was relatively high. Parental support for immunization registries may increase with greater parental awareness of the risks of vaccine preventable diseases and utility of vaccination.
Adult↗
Excretion of oral poliovirus vaccine strains: effect of vaccination schedule.
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Humans↗
Measuring immunization coverage among preschool children: past, present, and future opportunities.
Control of vaccine-preventable diseases depends on maintaining high levels of immunization coverage. Immunization coverage among preschool children remains suboptimal in some areas and sociodemographic subgroups, as well as for more recently introduced vaccines, leaving susceptible young children vulnerable to complications from vaccine-preventable diseases. This paper reviews approaches historically used to measure immunization coverage among preschool children in the United States. The strengths and weaknesses of various approaches to measuring immunization coverage among preschool children are explored, with emphasis on the current means to measure national immunization coverage-the National Immunization Survey. Methods for measuring immunization coverage among preschool children at local and state levels are also evaluated. Future opportunities and challenges for measuring immunization coverage at the local, state, and national levels are explored.
Centers for Disease Control and Prevention, U.S.↗
Poliovirus excretion in Guatemalan adults and children with HIV infection and children with cancer.
More than 20 patients with persistent poliovirus infections have been identified and reported to WHO. To date, almost all of these patients have had B-cell immune deficiency disorders. Since there are limited data on patients with HIV infection who have received oral poliovirus vaccine (OPV), we studied adults and children to determine if persons with acquired immunodeficiency due to HIV infection or cancer chemotherapy in a developing country setting had prolonged excretion of polioviruses. Stool samples from 94 HIV-infected children and 101 adults and 50 children surviving cancer in Guatemala City were cultured for polioviruses. No polioviruses were detected in any of the 195 persons with HIV infection or the 50 with cancer. The evidence from this and other studies indicates that the persistent poliovirus excretion in HIV-infected individuals is an unlikely event.
Adolescent↗
No evidence for prolonged excretion of polioviruses in persons with residual paralytic poliomyelitis in Ethiopia, Pakistan and Guatemala.
Persons who have developed acute flaccid paralysis following infection with wild-type polioviruses or vaccine-associated paralytic poliomyelitis usually excrete polioviruses for only a few weeks. However, some patients with paralytic poliomyelitis have had prolonged excretion of polioviruses for periods of up to 10 years after onset of disease. Most prolonged excretors have been identified in industrialized countries. We studied 348 patients 2-28 years old in Ethiopia, Pakistan and Guatemala with residual paralytic poliomyelitis to determine if they had IgA or IgG deficiency or persistent poliomyelitis excretion at least 1 year after onset of disease. None of the 348 affected individuals had IgG deficiency or persistent poliovirus excretion. One child had borderline low serum IgA concentration. Since we did not study children under 2 years of age, persons born with IgG deficiency disorders may have died in developing countries where replacement immunoglobulin therapy is not readily available. Nevertheless, persistent poliovirus excretion among persons 2 years of age and older with residual paralytic poliomyelitis is uncommon in developing countries.
Adolescent↗
Compulsory vaccination and conscientious or philosophical exemptions: past, present, and future.
Compulsory vaccination has contributed to the success of immunisation programmes in the USA and Australia, yet the benefits from compulsory vaccination are not universally recognised. Some people--experts and the public alike--believe that the benefits of compulsory vaccination are outweighed by the associated ethical problems. A review of vaccination legislation in the UK, Australia, and the USA raises four main points. First, compulsory vaccination may be effective in preventing disease outbreaks, reaching and sustaining high immunisation coverage rates, and expediting the introduction of new vaccines. Second, to be effective, compulsory programmes must have a reliable supply of safe and effective vaccines and most people must be willing to be vaccinated. Third, allowance of exemptions to compulsory vaccination may limit public backlash. Finally, compulsory vaccination may increase the burden on governments to ensure the safety of vaccines. Nevertheless, although compulsory immunisation can be very effective, it might not be acceptable in some countries where high coverage has been achieved through other approaches or efforts, such as in Sweden, Norway, Denmark, the Netherlands, and the UK. These factors should be considered when compulsory vaccinations are being introduced or immunisation laws refined. Lessons learned from compulsory vaccination could be useful to other public-health programmes.
Australia↗
Prediagnostic circulating antibodies to JC and BK human polyomaviruses and risk of non-Hodgkin lymphoma.
Viral infections have been associated with increased risk of non-Hodgkin's lymphoma (NHL). We conducted a nested case-control study to investigate the association between prediagnostic serum antibodies to the human polyomaviruses, JC (JCV) and BK (BKV), and subsequent risk of NHL. Two research serum banks were established in Washington County, Maryland, in 1974 and 1989, with the collection of blood samples from >45,000 volunteers. Incident NHL cases diagnosed through 2002 (n = 170) were identified among participants by linkage to population-based cancer registries. Two controls were matched to each case (n = 340) on age, sex, and blood draw date. Prediagnostic IgG antibodies to JCV and BKV were measured using virus-like particle ELISA. Associations between JCV and BKV antibody seropositivity and NHL were estimated using conditional logistic regression. Overall, neither antibodies to JCV [odds ratio (OR), 0.83; 95% confidence interval (95% CI), 0.56-1.23] nor BKV (OR, 0.98; 95% CI, 0.64-1.48) were associated with an increased risk of NHL. Results were similar after stratification by NHL subtype or induction period and adjustment for EBV seropositivity. Among those who donated blood in both 1974 and 1989, an increase in JCV antibody levels over time was associated with a 4-fold increased risk of NHL compared with a steep decline in antibody levels (OR, 4.59; 95% CI, 1.30-16.25; P(trend) = 0.02). Whereas JCV seropositivity was not associated with NHL overall, the finding of an increased risk of NHL associated with increasing antibody levels among those who were seropositive at baseline warrants further research into factors influencing reactivation of JCV infection.
Adult↗
Factors associated with refusal of childhood vaccines among parents of school-aged children: a case-control study.
BACKGROUND: The rate of nonmedical exemptions to school immunization requirements has been increasing, and children with exemptions have contributed to outbreaks of vaccine-preventable diseases. OBJECTIVES: To determine why parents claim nonmedical exemptions and to explore differences in perceptions of vaccines and vaccine information sources between parents of exempt and fully vaccinated children. DESIGN: Case-control study. SETTING: Colorado, Massachusetts, Missouri, and Washington. PARTICIPANTS: Surveys were mailed to the parents of 815 exempt children (cases) and 1630 fully vaccinated children (controls randomly selected from the same grade and school) recruited from 112 private and public elementary schools. Surveys were completed by 2435 parents (56.1%). MAIN OUTCOME MEASURES: Parental reports. RESULTS: Most children (209 [75.5%] of 277) with nonmedical exemptions received at least some vaccines. The most common vaccine not received was varicella (147 [53.1%] of 277 exempt children). The most common reason stated for requesting exemptions (190 [69%] of 277) was concern that the vaccines might cause harm. Parents of exempt children were significantly more likely than parents of vaccinated children to report low perceived vaccine safety and efficacy, a low level of trust in the government, and low perceived susceptibility to and severity of vaccine-preventable diseases. Parents of exempt children were significantly less likely to report confidence in medical, public health, and government sources for vaccine information and were more likely to report confidence in alternative medicine professionals than parents of vaccinated children. CONCLUSION: Continued efforts must be made to educate parents about the utility and safety of vaccines, especially parents requesting nonmedical exemptions to school immunization requirements.
Adult↗
Evaluation of non-specific effects of infant immunizations on early infant mortality in a southern Indian population.
OBJECTIVE: The aim of this study was to assess the relationship between receipt of routine childhood immunizations and infant mortality before 6 months of age. METHODS: This was an observational study of 10,274 infants, in a randomized trial of vitamin A supplementation, who received the study dose and survived to at least 1 week of age. The primary outcome was mortality before 6 months of age, analysed in Cox regression models as a function of vaccine receipt and gender. RESULTS: Receipt of Bacille Calmette Guerin (BCG) or diphtheria, tetanus, polio (DTP) vaccine was associated with significant reductions of one-half to two-thirds of mortality hazards; among girls, those who received both BCG and DTP experienced higher mortality than those who received only one of the two vaccines (hazards ratio 2.4; 95% confidence interval 1.2-5.0). CONCLUSION: The reduced mortality rate associated with receipt of BCG or DTP may be due to both biological and selection factors; the analyses regarding the combined effect of these vaccines and gender need to be replicated in other settings.
BCG Vaccine↗
Markers of past infection with simian virus 40 (SV40) and risk of incident non-Hodgkin lymphoma in a Maryland cohort.
Simian virus 40 (SV40) genome sequences have been detected in human non-Hodgkin lymphoma (NHL) tissues, and past infection with SV40 may be a risk factor for NHL. We conducted a population-based nested case-control study to investigate the association between serum antibodies to SV40 and incident NHL. Two research serum banks were established in Washington County, MD, with >45,000 volunteers contributing blood samples collected in 1974 and 1989. Incident cases of NHL diagnosed through 2002 (n = 170) were identified among participants by linkage to population-based cancer registries. Two controls were matched to each case (n = 340) on age, sex, and date of blood draw. Circulating immunoglobulin G antibodies to SV40 were measured using virus-like particle (VLP) ELISA. Positive samples were tested for cross-reactivity with JC virus (JCV) and BK virus (BKV) through competitive inhibition assays. Associations between SV40 antibody seropositivity and NHL were estimated using conditional logistic regression. Whereas SV40 antibodies were detected by VLP ELISA in 15% of cases and 10% of controls [matched odds ratio (OR), 1.97; 95% confidence interval (95% CI), 1.03-3.76], the SV40 reactivity of 85% of the SV40 antibody-positive sera was decreased by adsorption with BKV and/or JCV VLPs. Antibodies specific for SV40 (not cross-reactive) were identified in only 1.8% of cases and 1.6% of controls (OR, 1.51; 95% CI, 0.41-5.52). Our findings suggest that past infection with SV40 is not associated with an increased risk of developing NHL.
Antibodies, Viral↗
Public health and the politics of school immunization requirements.
Compulsory vaccination has contributed to the enormous success of US immunization programs. Movements to introduce broad "philosophical/personal beliefs" exemptions administered without adequate public health oversight threaten this success. Health professionals and child welfare advocates must address these developments in order to maintain the effectiveness of the nation's mandatory school vaccination programs. We review recent events regarding mandatory immunization in Arkansas and discuss a proposed nonmedical exemption designed to allow constitutionally permissible, reasonable, health-oriented administrative control over exemptions. The proposal may be useful in political environments that preclude the use of only medical exemptions. Our observations may assist states whose current nonmedical exemption provisions are constitutionally suspect as well as states lacking legally appropriate administrative controls on existing, broad non-medical exemptions.
Arkansas↗
Exemptions to school immunization requirements: the role of school-level requirements, policies, and procedures.
OBJECTIVES: Our goal was to determine whether school-level variability in implementation of immunization requirements is associated with the likelihood of a child having received an exemption to school immunization requirements. METHODS: We surveyed 1000 school immunization personnel in Colorado, Massachusetts, Missouri, and Washington. We explored associations between school implementation of immunization requirements and the likelihood of a child having an exemption using logistic regression models. RESULTS: School policies associated with an increased likelihood of children having exemptions included lack of provision of written instructions for completing the school immunization requirement before enrollment, administrative procedures making it easier to claim an exemption, and granting of philosophical exemptions. In the 2 states we surveyed where philosophical exemptions are not authorized (Massachusetts and Missouri), 17.0% and 18.1% of schools reported permitting philosophical exemptions. CONCLUSIONS: Inconsistencies in the interpretation and implementation of school immunization laws contribute to variability in rates of exemptions. School policies should be reviewed to ensure consistency with the intent of state laws.
Child↗
The clinical significance of measles: a review.
Forty years after effective vaccines were licensed, measles continues to cause death and severe disease in children worldwide. Complications from measles can occur in almost every organ system. Pneumonia, croup, and encephalitis are common causes of death; encephalitis is the most common cause of long-term sequelae. Measles remains a common cause of blindness in developing countries. Complication rates are higher in those <5 and >20 years old, although croup and otitis media are more common in those <2 years old and encephalitis in older children and adults. Complication rates are increased by immune deficiency disorders, malnutrition, vitamin A deficiency, intense exposures to measles, and lack of previous measles vaccination. Case-fatality rates have decreased with improvements in socioeconomic status in many countries but remain high in developing countries.
Adolescent↗
Knowledge, attitudes, and beliefs of school nurses and personnel and associations with nonmedical immunization exemptions.
OBJECTIVES: We studied school personnel involved in the review of student's immunization status to determine whether personnel training, immunization-related knowledge, attitudes, and beliefs, use of alternative medicine, and sources of vaccine information were associated with the vaccination status of school children. METHODS: Surveys were mailed to a stratified and random sample of 1000 schools in Colorado, Massachusetts, Missouri, and Washington. School personnel reported their training and perceptions of disease susceptibility/severity, vaccine efficacy/safety, key immunization beliefs, use of alternative medicine, confidence in organizations, sources, and credibility of vaccine information, and the rates of vaccine exemptors in their schools. Logistic regression analysis was used to explore associations between personnel factors and beliefs (independent variables) with the likelihood of a child having an exemption (dependent variable). Regression models were adjusted for clustering of children in schools, type of school (public versus private), and state. RESULTS: Surveys were returned by 69.6% of eligible participants. A child attending a school with a respondent who was a nurse was significantly less likely to be have an exemption than a child attending a school with a respondent who was not a nurse (odds ratio [OR]: 0.39; 95% confidence interval [CI]: 0.28-0.56). The majority of respondents believed that children (95.6%) and the community (96.1%) benefit when children are vaccinated. Nurses were more likely than nonnurses to hold beliefs supporting the utility and safety of vaccination. Greater perceived disease susceptibility and severity and vaccine efficacy and safety were associated with a decreased likelihood of a child in the school having an exemption. Vaccine misconceptions were relatively common. For example, 19.0% of respondents were concerned that children's immune systems could be weakened by too many immunizations, and this belief was associated with an increased likelihood of a child in the school having an exemption (OR: 1.51; 95% CI: 1.00-2.28). Most respondents had a moderate amount or great deal of confidence in state health departments (91.4%), the Centers for Disease Control and Prevention (CDC) (93.9%), local health departments (88.8%), health care providers (88.5%), the Food and Drug Administration (73.6%), and the health care system (65.2%). Fewer respondents had a moderate amount or great deal of confidence in the media (17.4%). A child attending a school with a respondent who had a moderate amount or great deal of confidence in local and state health departments was less likely to have an exemption (OR: 0.47 and 0.44; 95% CI: 0.27-0.80 and 0.25-0.80, respectively) than a child attending a school with a respondent who did not have a moderate amount or great deal of confidence in local and state health departments. Confidence in other groups was not associated with the likelihood of a child in the school having an exemption. Nearly half (45.5%) of the respondents or their immediate family members had used some form of alternative medicine in the last 5 years. A child attending a school with a respondent who had (or had a family member[s] who) used an alternative medicine practitioner was more likely to have an exemption than a child attending a school with a respondent who had not used an alternative medicine practitioner. There were significant associations between sources used and perception of reliability for vaccine information with the likelihood of a child in the school having an exemption. Use of professional organizations, government resources, vaccine companies, and pharmacists for vaccine information were associated with a decreased likelihood of a child in the school having an exemption. Perceiving health departments and the CDC as a good or excellent source for vaccine information was associated with a decreased likelihood of a child in the school having an exemption. CONCLUSIONS: The training, knowledge, attitudes, and beliefs of school personnel who work with parents on immunrk with parents on immunization issues were associated with the likelihood of a child in the school having an exemption. Although respondents generally believed in vaccinations, misconceptions were common. Many school personnel seem to be unaware of the seriousness of some vaccine-preventable diseases and that unimmunized children are highly susceptible to diseases. These misperceptions were associated with an increased likelihood of a child having an exemption. This study of associations cannot determine causal associations. Nonetheless, the frequency of vaccine misconceptions among school personnel warrants vaccine communication programs for school employees who work with parents on immunization issues. An intervention study could determine whether such programs have an impact on parental decisions to claim exemptions for their children. Personnel without formal health care training who advice parents on immunization issues could be passing on misinformation to parents. Nurses or properly trained health personnel should be the primary school contacts for parents on immunization issues. Health departments and health care providers were used most often by school personnel for vaccine information. Providers, professional organizations, health departments, and the CDC were considered most credible. The CDC may be an underutilized source, given its high credibility; only 58.1% of respondents reported using the CDC for vaccine information. Greater visibility of CDC on vaccine information statements and communication efforts from the CDC directly to school personnel will likely be well received. Respondents who do not consider health departments and the CDC as credible sources were associated with a greater likelihood of a child in their school having an exemption. The CDC may need to consider working with other reliable sources to communicate with these personnel. Studies are needed to understand why some parents choose to forgo vaccination for children who do not have true medical contraindications to vaccines. School personnel trained in vaccine safety may serve as a valuable source of vaccine information for parents. Parents who have misconceptions about vaccines would likely benefit from discussions with health care providers. Additional public-information campaigns regarding misconceptions and the value of vaccination may be needed.
Allied Health Personnel↗
Enhancing public confidence in vaccines through independent oversight of postlicensure vaccine safety.
The National Immunization Program of the Centers for Disease Control and Prevention is responsible for controlling infectious diseases through vaccination, but the program also plays a key role in postlicensure vaccine safety assessment. The time has come to separate postlicensure vaccine safety assessment from vaccine risk management as recommended by the National Research Council of the National Academy of Sciences.The National Transportation Safety Board offers a useful model for developing an independent National Vaccine Safety Board that would have the authority to leverage resources and expertise of various government agencies, academia, and industry to oversee postlicensure vaccine safety investigations. Such a board would have been useful in recent vaccine safety concerns, and its independence from government programs would ensure optimal vaccine safety and enhance public confidence in vaccines.
Centers for Disease Control and Prevention, U.S.↗
Search for poliovirus carriers among people with primary immune deficiency diseases in the United States, Mexico, Brazil, and the United Kingdom.
OBJECTIVE: To estimate the rate of long-term poliovirus excretors in people known to have B-cell immune deficiency disorders. METHODS: An active search for chronic excretors was conducted among 306 persons known to have immunoglobulin G (IgG) deficiency in the United States, Mexico, Brazil, and the United Kingdom, and 40 people with IgA deficiency in the United States. Written informed consent or assent was obtained from the participants or their legal guardians, and the studies were formally approved. Stool samples were collected from participants and cultured for polioviruses. Calculation of the confidence interval for the proportion of participants with persistent poliovirus excretion was based on the binomial distribution. FINDINGS: No individuals with long-term excretion of polioviruses were identified. Most participants had received oral poliovirus vaccine (OPV) and almost all had been exposed to household contacts who had received OPV. Polioviruses of recent vaccine origin were transiently found in four individuals in Mexico and Brazil, where OPV is recommended for all children. CONCLUSION: Although chronic poliovirus excretion can occur in immunodeficient persons, it appears to be rare.
Adolescent↗