Trial of Edmonston-Zagreb measles vaccine in infants aged under nine months.

Due to the recent finding that most infants in developing countries have lost maternal antibody for measles before nine months of age, immunization of infants younger than the recommended age of nine months would help reducing the incidence of measles in these endemic areas. We conducted a trial of Edmonston-Zagreb measles vaccine which is the strain that may be more immunogenic in young infants than the widely used Schwarz strain. Forty-five infants with mean age of 25 weeks received a dose of Edmonston-Zagreb vaccine. Antibody levels were measured, using plaque neutralization test, before and about 3 months after vaccination at which mean age was 38 weeks. The seroconversion rate was 89%. Only two infants (4.4%) had immunity before vaccination. Fifteen infants (33.33%) reported some adverse reactions including fever (13.33%), rhinorrhea (8.89%), rash (4.44%) and local reactions (22.22%). All of the reactions resolved spontaneously. We conclude that Edmonston-Zagreb measles vaccine is efficacious and safe in infants aged under nine months.     

Evaluation of urban measles mass campaigns for children aged 9-59 months in Mali

There are an estimated 234,000 cases of measles and 13,851 measles-related deaths per year in Mali. In 1998 and 1999, 548,309 children aged 9-59 months were vaccinated against measles during mass campaigns in urban centers across Mali. After the first campaign, measles incidence decreased by 95% in districts encompassing vaccinated urban centers and by 41% in nonvaccinated districts. There was no shift in the proportion of cases by age group in vaccinated centers. Measles in vaccinated districts after the campaign was likely related to persistent transmission in age groups not targeted for vaccination and among children living in nonvaccinated districts. The second campaign (1999) did not change the incidence of measles in vaccinated compared with nonvaccinated centers. Urban mass measles vaccination probably did not affect overall measles transmission in Mali. Mass vaccination of all children in Mali, targeting a larger age group, will be necessary to reach measles control objectives.     

Immune responses to measles and mumps vaccination of infants at 6, 9, and 12 months

Immunizing infants against measles at the youngest age possible has the potential to reduce morbidity and mortality. The ability of infants at 6, 9, or 12 months to respond to measles and mumps vaccines was evaluated by measuring T cell proliferation, interferon-gamma production, and neutralizing antibody titers before and after vaccination. Infants in all age groups had equivalent cellular immune responses to measles or mumps viruses, with or without passive antibodies when immunized. In contrast, 6-month-old infants without passive antibodies had low geometric mean titers of antibody to measles or mumps viruses and low seroconversion rates. Geometric mean titers of antibody to measles virus increased if infants were revaccinated at 12 months. Six-month-old infants had limited humoral responses to paramyxovirus vaccines, whereas cellular immunity was equivalent to that of older infants. T cell responses can be established by immunization with these live attenuated virus vaccines during the first year, despite the presence of passive antibodies.     

9月龄～6岁健康儿童麻疹和风疹抗体水平监测

目的 了解新疆阿克苏地区9月龄～6岁健康儿童麻疹和风疹抗体水平,及时发现免疫薄弱人群,采取针对性免疫措施.方法 采用分层随机抽样法,采集839名9月龄～6岁健康儿童血清标本,采用酶联免疫吸附试验(ELISA)检测麻疹和风疹IgG抗体.结果 839名儿童麻疹抗体阳性率为94.3％,抗体几何平均滴度(GMT)为1 541.2 mIU/ml;风疹抗体阳性率为92.1％,抗体几何平均滴度(GMT)为958.4 mIU/ml.不同免疫剂次和不同年龄组儿童麻疹、风疹抗体阳性率和GMT水平不同,差异有统计学意义(P＜0.05).结论 阿克苏地区9月龄～6岁健康儿童麻疹、风疹IgG抗体水平总体较高,但仍存在薄弱环节,1岁以下儿童是麻疹和风疹的高危人群,应加强此部分人群的针对性免疫策略.     

Immunogenicity of standard dose Edmonston-Zagreb measles vaccine in highland Papua New Guinean children from four months of age

A small-scale trial was carried out at Tari in the Southern Highlands Province of Papua New Guinea to determine the effectiveness of a standard subcutaneous dose of Edmonston-Zagreb measles vaccine (Institute of Immunology, Zagreb) administered to children at less than 8 months of age. Specific antibody levels were measured before and 7-11 weeks after vaccination using an ELISA system. Paired sera from 41 children vaccinated at 4-7 months of age and from 18 children vaccinated routinely at 8-29 months of age were available for comparison. No child 6 months of age or older had detectable maternal antibodies and all of these seroconverted. Post-vaccination titres in 12 children aged 6-7 months were not significantly different from those in older children and 1 year later, post-vaccination titres were still high. In Papua New Guinea, and perhaps in other developing countries, it may prove appropriate and acceptable to vaccinate with Edmonston-Zagreb measles vaccine at 6 months of age without recourse to augmentation of dose from that currently recommended in older children.     

Impact of nationwide measles vaccination campaign among children aged 9 months to 14 years,Zimbabwe, 1998-2001

Zimbabwe (population 11,365,000) introduced nationwide one-dose measles vaccination in 1981. This strategy reached 70%-80% of infants <1 year of age over the next two decades; in 1998, a nationwide supplemental immunization activity (SIA) targeting all children aged 9 months to 14 years achieved 93% coverage. Surveillance data were examined to determine the impact of these strategies. During 1985-1997, there were 8529-49,812 measles cases annually. After the SIA, laboratory confirmation of the first 5 outbreak cases and all sporadic cases was required. In 1999 and 2000, 1343 (88%) of 1534 suspected cases had adequate specimens submitted and 28 (2%) were measles IgM positive. In 2001, of 529 suspected cases, 513 (97%) had adequate specimens and only 7 (1%) were measles IgM positive. These data suggest that indigenous measles transmission in Zimbabwe has been interrupted and that high prevalence of human immunodeficiency virus seropositivity does not hinder vaccination-induced measles control. High vaccination coverage obtained through the routine health care system supplemented by periodic follow-up SIAs will be required to maintain low transmission levels.     

Global distribution of measles genotypes and measles molecular epidemiology

A critical component of laboratory surveillance for measles is the genetic characterization of circulating wild-type viruses. The World Health Organization (WHO) Measles and Rubella Laboratory Network (LabNet), provides for standardized testing in 183 countries and supports genetic characterization of currently circulating strains of measles viruses. The goal of this report is to describe the lessons learned from nearly 20 years of virologic surveillance for measles, to describe the global databases for measles sequences, and to provide regional updates about measles genotypes detected by recent surveillance activities. Virologic surveillance for measles is now well established in all of the WHO regions, and most countries have conducted at least some baseline surveillance. The WHO Global Genotype Database contains >7000 genotype reports, and the Measles Nucleotide Surveillance (MeaNS) contains >4000 entries. This sequence information has proven to be extremely useful for tracking global transmission patterns and for documenting the interruption of transmission in some countries. The future challenges will be to develop quality control programs for molecular methods and to continue to expand virologic surveillance activities in all regions.     

Clinical measles after measles virus challenge in simian immunodeficiency virus-infected measles virus-vaccinated rhesus monkeys

Understanding the impact of human immunodeficiency virus (HIV) infection on the clinical manifestations and kinetics of measles virus (MV) replication in MV-vaccinated and unvaccinated individuals is important for developing successful vaccine strategies for measles eradication. To model the pathogenesis of MV infection in MV-vaccinated and unvaccinated individuals infected with HIV, previously vaccinated and unvaccinated rhesus monkeys infected with simian immunodeficiency virus (SIV) were challenged with MV and monitored for clinical, virologic, and immunologic sequelae of infection. The magnitude and duration of MV viremia were unchanged by SIV infection. Nevertheless, clinical manifestations of MV infection were altered in animals with significant CD4(+) T lymphocyte loss. Importantly, 2 of the 3 SIV-infected monkeys with high titers of vaccine-induced MV-neutralizing antibody developed clinical evidence of MV infection. Thus, in this experimental animal model, a high-titer vaccine-induced MV-neutralizing antibody response does not protect against clinical manifestations of measles in the setting of a chronic acquired immunodeficiency syndrome virus infection.     

Restriction of measles virus gene expression in measles inclusion body encephalitis

Measles virus (MV) infection in brain tissue of a patient with measles inclusion body encephalitis was characterized by immunologic and biochemical techniques. Of the five major structural proteins of MV, only nucleocapsid (N) protein and phosphoprotein (P protein) were consistently detected in diseased brain areas. In contrast, hemagglutinin protein was seen only occasionally, and no membrane and fusion proteins were found in any of the sections studied. Messenger RNAs (mRNAs) specific for these five viral proteins were detected in all brain extracts examined; however, the mRNAs for the envelope proteins were clearly underrepresented in comparison with lytically infected cells. Only the mRNAs for N and P proteins appeared active in in vitro translations. These findings indicate quantitative differences in the pattern of mRNA expression in brain tissue and a restricted expression of MV envelope proteins in infected cells as observed in subacute sclerosing panencephalitis.     

Clinical features of measles according to age in a measles epidemic

The purpose of this study was to retrospectively investigate the relationship between age and clinical manifestations and laboratory findings in patients with measles. The study included 216 patients admitted to a hospital in Daejeon, 1 of the largest cities in South Korea, during the 2000-2001 measles outbreak: very young children (<2 y old; 159 patients), school age children (9-11 y old; 34 patients), and young adults (>16 y old; 23 patients). Few of the very young children (9%), but most of the older children (86%) had a history of a prior measles-mumps-rubella vaccination. There were no statistical differences between the 3 groups in terms of the total duration of fever, length of hospitalization, occurrence of complications (defined as hospitalization for more than 7 d) or anti-measles IgM positivity. A reduction in the number of white blood cells and lymphocytes was observed in all age groups. The levels of C-reactive protein were not different between very young children and older children, but hepatic involvement was more prevalent in young adults. In conclusion, the clinical course including the complications experienced was similar in all the measles patients regardless of age.     

An outbreak of measles among unvaccinated young adults and measles seroprevalence study: implications for measles outbreak control in adult populations

Measles incidence has declined significantly in the United States since the 1989-1991 resurgence. Several conditions, including pockets of underimmunization, international importation, and the inability to rapidly detect and contain cases, represent potential threats to this success. During the 1995-1996 winter holiday season, the Minnesota Department of Health investigated an outbreak of measles among unvaccinated young adults affiliated with a religious community. A total of 26 outbreak-associated cases of measles were identified; most case patients (65%) were 20-29 years of age (range, 18 months to 35 years). Although case patients had multiple opportunities to expose the general public, no subsequent transmission was identified despite extensive surveillance efforts. A measles seroprevalence survey of 508 Minnesota blood donors aged 20-39 years was conducted; 91% had serological evidence of immunity to measles. Our findings illustrate that high levels of population immunity can prevent transmission of measles, despite multiple opportunities for exposure.     

Impact of measles in France

Although measles vaccine has been licensed since 1968, immunization against measles has not met with much success in France, partly because the disease is no longer feared. The level of vaccination coverage appears to be less than 20%. Indeed, the present epidemiologic situation is similar to the natural situation in a developed country. A multicenter, retrospective hospital survey revealed that 1,157 patients with measles were hospitalized during a 30-month period in five areas (total population, 4.2 million). Analysis of the preliminary results of this survey and of available national data showed an incidence of 5.6-7.5 cases per 1,000 population; a hospitalization rate of one per 10,000; a death rate of 0.56 per 1 million; and a disability rate of 0.48 per 1 million. Encephalitis (the definition of which should be reappraised) occurred once in 2,850 cases, and subacute sclerosing panencephalitis was not rare (incidence, one case per 2.6 million people). The problem posed by measles is sufficiently grave to justify a national campaign urging the widespread vaccination of children.