Measles outbreak in 31 schools: risk factors for vaccine failure and evaluation of a selective revaccination strategy.

OBJECTIVE: To examine the risk factors for measles vaccine failure and to evaluate the effectiveness of a selective revaccination strategy during a measles outbreak. DESIGN: Matched case-control study. SETTING: Thirty-one schools in Mississauga, Ont. SUBJECTS: Eighty-seven previously vaccinated school-aged children with measles that met the Advisory Committee on Epidemiology''s clinical case definition for measles. Two previously vaccinated control subjects were randomly selected for each case subject from the same homeroom class. INTERVENTIONS: All susceptible contacts were vaccinated, and contacts who had been vaccinated before Jan. 1, 1980, were revaccinated. When two or more cases occurred in a school all children vaccinated before 1980 were revaccinated. MAIN OUTCOME MEASURES: Risk of measles associated with age at vaccination, time since vaccination, vaccination before 1980 and revaccination. RESULTS: Subjects vaccinated before 12 months of age were at greater risk of measles than those vaccinated later (adjusted odds ratio [OR] 7.7, 95% confidence interval [CI] 1.6 to 38.3; p = 0.01). Those vaccinated between 12 and 14 months of age were at no greater risk than those vaccinated at 15 months or over. Subjects vaccinated before 1980 were at greater risk than those vaccinated after 1980 (adjusted OR 14.5, 95% CI 1.5 to 135.6). Time since vaccination was not a risk factor. Revaccination was effective in reducing the risk of measles in both subjects vaccinated before 1980 and those vaccinated after 1980 (adjusted OR reduced to 0.6 [95% CI 0.1 to 5.3] and 0.3 [95% CI 0.13 to 2.6] respectively). However, only 18 cases were estimated to have been prevented by this strategy. CONCLUSIONS: Adherence to routine measles vaccination for all eligible children is important in ensuring appropriate coverage with a single dose. The selective revaccination strategy''s high labour intensiveness and low measles prevention rate during the outbreak bring into question the effectiveness of such a strategy.     

Subacute sclerosing panencephalitis in Croatia (1994-2004)

We studied five patients with SSPE during a 10-year period (1994-2004). The first clinical symptoms developed at the age of 5-11 years. All patients were vaccinated regularly against measles according to the official immunization schedule. One patient had measles at the age of 18 months. Two of them had a history of morbilliform rash (unrecognized measles) at the age of six and seven months, respectively. In two patients, with no history of measles before vaccination the disease started after varicella infection. Using complement-fixation (F) test and EIA, antibodies to measles virus (MV) were detected in the CSF and sera of all patients. The CF-antibody titers ranged from 1:1024 to 1:65536 in sera and from 1:16 to 1:128 in CSF samples. MV antigen was detected in brain imprints using IFA in two patients. Electron microscopic analysis revealed intranuclear viral inclusions (MV nucleocapsids). Using RT-PCR, viral RNA was found in both patients. Nucleotide sequence analysis showed that the viruses found in the brain tissue belonged to the wild-type MV D6 genotype [7].     

Swedish experience of two dose vaccination programme aiming at eliminating measles,mumps, and rubella.

In 1982 a two dose regimen was introduced in Sweden for the combined vaccination against measles, mumps, and rubella of children aged 18 months and 12 years. Since 1977 about half of the preschool children were vaccinated against measles annually, and since 1974 about 80% of 12 year old girls were vaccinated against rubella. During the period 1982 to 1985 90-93% of the eligible age cohorts of 18 month old children and 88-91% of the 12 year old children were immunised with the new combined vaccine. A study in 1982 of about 140 18 month old children who were nearly all seronegative before vaccination showed that 96%, 92%, and 99% seroconverted against measles, mumps, and rubella, respectively. A second study was carried out in 1983 of 247 12 year old children, of whom 11% lacked antibodies to measles, 27% to mumps, and 45% to rubella. This showed seroconversion in 82% and 80% against measles and mumps, respectively, and all children seroconverted against rubella. In the latest study in 1985 of 496 12 year olds 9% and 13% were seronegative against measles and mumps before vaccination, and 41% against rubella. Of these, 88% seroconverted to measles and 80% to mumps, and all converted to rubella when sera were tested by the haemolysis in gel method. After a neutralisation test against measles as well all children showed immunity to the disease. A low incidence of measles and declining figures for mumps and rubella were reported in 1984 to 1986. An outbreak of rubella during 1985 affected mainly boys in age cohorts in which only the girls had been vaccinated during the 1970s.     

Decline in measles mortality: nutrition,age at infection,or exposure?

The mortality from measles was studied in an urban area of Guinea-Bissau one year before and five years after the introduction of a vaccination programme. The years after the introduction of immunisation saw a decline in mortality among unvaccinated children with measles. This decline occurred despite a lower age at infection and an increasing prevalence of malnourished children. State of nutrition (weight for age) did not affect the outcome of measles infection. The incidence of isolated cases, however, increased in the period after the introduction of measles vaccination. As mortality was lower among these cases, diminished clustering explained some of the reduction in mortality. Comparison between the urban district and a rural area inhabited by the same ethnic group showed a lower age at infection, less clustering of cases, and lower case fatality ratios in the urban area.Endemic transmission of measles in urban districts leads to less clustering of cases, which may help explain the usually lower case fatality ratios in these areas. As measles vaccination increases herd immunity and diminishes clustering of cases, it may reduce mortality even among unvaccinated children who contract the disease.     

Evaluation of the eight-year period of compulsory measles vaccination in the Czech Socialist Republic (CSR)

The object of the study is the evaluation of a more than 8-year period of compulsory vaccination against measles in the CSR. So far, a total of 1,850,000 children have been vaccinated. A pronounced decrease has been achieved in morbidity while mortality and lethality reached zero values as early as in 1973. Changes occur in the epidemiological characteristic of measles manifested primarily by the shift of the age distribution of notified cases into older age groups, by continuous prolongation of interepidemic intervals and by gradual disappearances of typical seasonal incidence. Regular immunological surveys have become the most efficient tools in epidemiological surveillance of this infection and in monitoring the vaccination programme. The results of immunological surveys indeed led to the introduction in 1975 of so-called second vaccination compulsory for children starting the first year of school attendance. Up to the present, a total of 24,000 cases of measles have been recorded in children vaccinated earlier, i.e., 1.5% of the total of vaccinated children. It can be expected that measles as a mass disease will be eliminated from the territory of the CSR in the next few years.     

Cell mediated immunity after measles in Guinea-Bissau: historical cohort study.

OBJECTIVE: To investigate whether children who have had measles have reduced general cell mediated immunity three years later compared with vaccinated children who have not had measles. DESIGN: Historical cohort study. SETTING: Bissau, Guinea-Bissau. SUBJECTS: 391 children aged 3-13 years who were living in Bissau during a measles epidemic in 1991 and still lived there. These included 131 primary cases and 139 secondary cases from the epidemic and 121 vaccinated controls with no history of measles. MAIN OUTCOME MEASURES: General cell mediated immunity assessed by measurement of delayed type hypersensitivity skin responses to seven recall antigens. Anergy was defined as a lack of response to all antigens. RESULTS: 82 out of 268 cases of measles (31%) were anergic compared with 20 of the 121 vaccinated controls (17%) (odds ratio adjusted for potential confounding variables 2.2 (95% confidence interval 1.2 to 4.0); P 0.009). The prevalence of anergy was higher in secondary cases (33% (46/138)) than in primary cases (28% (36/130)), although this difference was not significant. Anergy was more common in the rainy season (unadjusted prevalence 31% (91/291) than in the dry season (11% (11/98)) (adjusted odds ratio 4.8 (2.2 to 10.3)). This seasonal increase occurred predominantly in the case of measles. CONCLUSION: Reduced general cell mediated immunity may contribute to the higher long term mortality in children who have had measles compared with recipients of standard measles vaccine and to the higher child mortality in the rainy season in west Africa.     

Symptoms after accelerated immunisation.

OBJECTIVE--To document the incidence of symptoms after accelerated immunisation with diphtheria-tetanus-pertussis vaccine. DESIGN--Controlled study of children immunised with adsorbed diphtheria-tetanus-pertussis vaccine at accelerated and standard schedules. SETTING--Colchester and north Hertfordshire. SUBJECTS--107 children scheduled to receive immunisation at 2, 3, and 4 months of age and 115 children scheduled to receive immunisation at 3, 4 1/2 to 5, and 8 1/2 to 11 months of age. MAIN OUTCOME MEASURES--Parentally recorded symptoms, axillary temperatures, and size of local redness and swelling at the injection site during the seven days after immunisation. RESULTS--In general symptoms occurred less frequently with the accelerated schedule. Proportions of parents reporting axillary temperatures greater than 37.2 degrees C or local redness or swelling greater than 2.5 cm after the third dose of vaccine were significantly reduced in the accelerated schedule group. CONCLUSION--Immunisation at 2, 3, and 4 months of age is likely to cause fewer reactions than immunisation at 3, 4 1/2 to 5, and 8 1/2 to 11 months of age.     

Measles Outbreak in South Africa: Epidemiology of Laboratory-Confirmed Measles Cases and Assessment of Intervention, 2009–2011

Background

Since 1995, measles vaccination at nine and 18 months has been routine in South Africa; however, coverage seldom reached >95%. We describe the epidemiology of laboratory-confirmed measles case-patients and assess the impact of the nationwide mass vaccination campaign during the 2009 to 2011 measles outbreak in South Africa.

Methods

Serum specimens collected from patients with suspected-measles were tested for measles-specific IgM antibodies using an enzyme-linked immunosorbent assay and genotypes of a subset were determined. To estimate the impact of the nationwide mass vaccination campaign, we compared incidence in the seven months pre- (1 September 2009–11 April 2010) and seven months post-vaccination campaign (24 May 2010–31 December 2010) periods in seven provinces of South Africa.

Results

A total of 18,431 laboratory-confirmed measles case-patients were reported from all nine provinces of South Africa (cumulative incidence 37 per 100,000 population). The highest cumulative incidence per 100,000 population was in children aged <1 year (603), distributed as follows: <6 months (302/100,000), 6 to 8 months (1083/100,000) and 9 to 11 months (724/100,000). Forty eight percent of case-patients were ≥5 years (cumulative incidence 54/100,000). Cumulative incidence decreased with increasing age to 2/100,000 in persons ≥40 years. A single strain of measles virus (genotype B3) circulated throughout the outbreak. Prior to the vaccination campaign, cumulative incidence in the targeted vs. non-targeted age group was 5.9-fold higher, decreasing to 1.7 fold following the campaign (P<0.001) and an estimated 1,380 laboratory-confirmed measles case-patients were prevented.

Conclusion

We observed a reduction in measles incidence following the nationwide mass vaccination campaign even though it was conducted approximately one year after the outbreak started. A booster dose at school entry may be of value given the high incidence in persons >5 years.     

2010—2012年度季节性流行性感冒疫苗对6～59月龄儿童保护效果的病例对照研究

目的评价2010—2012年度季节性流行性感冒疫苗(流感疫苗)对儿童的上市后保护效果。方法选择2010—2012年度6~59月龄的实验室诊断流感病例为病例组,在儿童预防接种信息系统中随机选择健康儿童为对照组,进行1∶2匹配的病例对照研究,采用条件Logistic回归计算保护效果。结果研究中共纳入1 255组研究对象。2010—2011和2011—2012年度,流感疫苗对6~59月龄儿童完全免疫的保护效果分别为73.2%(95%可信限(CI):52.2~85.0)和52.9%(95%CI:42.1~61.7),对6~35月龄儿童的保护效果优于36~59月龄儿童,完全免疫的保护效果优于部分免疫。流感疫苗的保护效果从1~3月的68.9%(95%CI:57.5~77.2)衰减至4~6月的48.4%(95%CI,33.8~59.7)。结论流感疫苗对6~59月龄儿童具有一定的保护效果,儿童接种疫苗后可以减少52.9%~73.2%的流感病例,建议儿童每年及时进行全程免疫。     

Revaccination of children during school-based measles outbreaks: potential impact of a new policy recommendation.

OBJECTIVE: To evaluate the potential impact of revaccination on measles outbreak control during school-based epidemics. DESIGN: Retrospective cohort study. SETTING: Thirty-two public elementary and high schools in 14 communities on the west island of Montreal. PARTICIPANTS: All 19,439 children attending these schools during the 1989 measles epidemic in Quebec. INTERVENTION: After notification of a case children with provider-verified records of vaccination on or after their first birthday were identified; the remaining children were vaccinated or excluded from school. OUTCOME MEASURE: Clinical or confirmed measles cases not prevented by this intervention that could have been prevented had revaccination been included during the outbreak. RESULTS: Of the 88 measles cases (74 confirmed) proof of one adequate vaccination was present in 48 (55%). Intervention generally occurred within 5 school days after case notification. The nonpreventable cases involved 75 children who had measles onset before the intervention and 11 (7 vaccinated) who had onset within 8 days after the intervention. The two remaining cases occurred 20 and 25 days after the intervention among nonvaccinated students who refused to be vaccinated. Except for these two cases measles was eliminated at every school. Application of the new Canadian guidelines for measles outbreak control would have required the administration of at least 10,000 additional doses during the outbreak to students vaccinated before 1980; implementation of the new US guidelines would have required the administration of 16,629 additional doses to children previously vaccinated only once. Well-enforced provincial regulations ensuring vaccination of every student upon school entry might have prevented 38 (43%) of the cases. The US recommendation of two routine doses of vaccine before school entry might have prevented 86 (98%) of the cases. However, revaccination during the outbreak would not have prevented a single additional case. CONCLUSION: Revaccination of previously vaccinated students during a measles outbreak would have been costly and of little benefit.     

Analysis of a measles epidemic; possible role of vaccine failures.

A measles epidemic occurred in the Greensville (Ont.) Unit schools during January and February 1975. There were 47 cases of measles in 403 students: 26 (55%) of the children had a history of being vaccinated and 18 (38%) had not been vaccinated. Among children known to have been vaccinated at less than 1 year of age 7 of 13 contracted measles, while among the 48 children who had not been vaccinated 18 contracted measles. The attack rate among vaccinees increased with increasing time since vaccination. The observations of this study as well as those of similar studies suggest that vaccine failures contributed to the genesis of the epidemic. It is recommended that all children initially vaccinated at less than 1 year of age should be revaccinated with live attenuated measles virus vaccine.     

The effect of maternal and child health and family planning services on mortality: is prevention enough?

OBJECTIVE--To examine the impact on mortality of a child survival strategy, mostly based on preventive interventions. DESIGN--Cross sectional comparison of cause specific mortality in two communities differing in the type, coverage, and quality of maternal and child health and family planning services. In the intervention area the services were mainly preventive, community based, and home delivered. SUBJECTS--Neonates, infants, children, and mothers in two contiguous areas of rural Bangladesh. INTERVENTIONS--In the intervention area community health workers provided advice on contraception and on feeding and weaning babies; distributed oral rehydration solution, vitamin A tablets for children under 5, and ferrous fumarate and folic acid during pregnancy; immunised children; trained birth attendants in safe delivery and when to refer; treated minor ailments; and referred seriously ill people and malnourished children to a central clinic. MAIN OUTCOME MEASURES--Overall and age and cause specific death rates, obtained by a multiple step "verbal autopsy" process. RESULTS--During the two years covered by the study overall mortality was 17% lower among neonates, 9% lower among infants aged 1-5 months, 30% lower among children aged 6-35 months, and 19% lower among women living in the study area than in those living in the control area. These differences were mainly due to fewer deaths from neonatal tetanus, measles, persistent diarrhoea with severe malnutrition among children, and fewer abortions among women. CONCLUSIONS--The programme was effective in preventing some deaths. In addition to preventive components such as tetanus and measles immunisation, health and nutrition education, and family planning, curative services are needed to reduce mortality further.     

Interpretation of the PPD skin test in BCG-vaccinated children.

Skin testing with 5 tuberculin units (TU) of purified protein derivative (PPD) of tuberculin stabilized with polysorbate (Tween) 80 was done 3 months and 1 year after immunization with bacille Calmette-Guérin (BCG) vaccine in two groups of children: one group vaccinated at birth and another group at age 6 years. Interpretation of the PPD skin test with 5 TU is possible in children 1 year and older vaccinated with BCG at birth: if the diameter of induration is more than 10 to 12 mm the reaction cannot be ascribed to BCG vaccination and is highly suggestive of supervening infection with Mycobacterium tuberculosis or occasionally atypical mycobacteria. In contrast, the interpretation of a PPD test in children vaccinated at age 6 years is extremely difficult.     

Effect of expanded US recommendations for seasonal influenza vaccination: comparison of two pediatric emergency departments in the United States and Canada

Background:

Starting in the 2006/2007 influenza season, the US Advisory Committee on Immunization Practices expanded its recommendations for seasonal influenza vaccination to include healthy children aged 24–59 months. The parallel Canadian organization, the National Advisory Committee on Immunization, did not at that time issue a similar recommendation, thereby creating a natural experiment to evaluate the effect of the policy in the United States.

Methods:

We examined data for 2000/2001 through 2008/2009 and estimated relative changes in visits to the emergency department for influenza-like illness at two pediatric hospitals, one in Boston, Massachusetts, and the other in Montréal, Quebec, following the US policy change. Models were adjusted for virologic factors, seasonal trends and all-cause utilization of the emergency department.

Results:

Of 1 043 989 visits to the emergency departments of the two hospitals for any reason during the study period, 114 657 visits were related to influenza-like illness. Adjusted models estimated a 34% decline in rates of influenza-like illness among children two to four years old in the US hospital relative to the Canadian hospital (rate ratio 0.66, 95% confidence interval 0.58–0.75) following the 2006 policy change of the Advisory Committee on Immunization Practices. This was accompanied by more modest declines of 11% to 18% for the other age groups studied.

Interpretation:

The divergence in influenza rates among children in the US and Canadian sample populations after institution of the US policy to vaccinate children two to four years of age is evidence that the recommendation of the US Advisory Committee on Immunization Practices resulted in a reduction in influenza-related morbidity in the target group and may have indirectly affected other pediatric age groups. Provincial adoption of the 2010 recommendation of teh National Advisory Committee on Immunization in Canada to vaccinate childen two to four years of age might positively affect influenza morbidity in Canada.Seasonal influenza is an important cause of visits to the emergency department among children during winter months, and its control and prevention rely on annual vaccination.^1–4 In the United States, the Advisory Committee on Immunization Practices is responsible for guiding immunization practices, and it revises its recommendations annually. Until the 2004/2005 influenza season, vaccination was targeted to primarily older individuals and those with certain medical conditions.⁵ On the basis of evidence that young children are at elevated risk for admission to hospital because of influenza-related complications, the recommendations were expanded for the 2004/2005 season to include healthy children aged 6–23 months.⁶Starting in the 2006/2007 season, the recommendations of the Advisory Committee on Immunization Practices regarding influenza vaccination were expanded again to include healthy children aged 24–59 months, a shift that added 10.6 million children to the target group.⁷ For the 2008/2009 season, recommendations were further expanded to include all persons 6 months to 18 years old,⁸ and for the 2010/2011 season, the influenza vaccine was advised for all individuals over 6 months of age.⁹In Canada, the National Advisory Committee on Immunization is the federal organization responsible for guiding the use of vaccines. Until the 2006/2007 season, the recommendations of this committee for the use of seasonal influenza vaccines were harmonized with those of its US counterpart. However, it was not until the 2010/2011 season that the Canadian committee began recommending that children two to four years old be routinely vaccinated against influenza, and not all Canadian provinces have adopted this recommendation.We aimed to examine the effect of the 2006 recommendation of the Advisory Committee on Immunization Practices to expand influenza vaccination coverage to preschool-aged children. Interannual variation in severity of disease and effectiveness of the vaccine make it difficult to directly estimate the effect of an intervention on the incidence of influenza in any given community. Instead, we compared surveillance data from the emergency departments of two pediatric hospitals, one in Boston, Massachusetts, and the other in Montréal, Quebec, cities with similar epidemiologic dynamics for seasonal influenza.¹⁰ Our specific objective was to estimate the relative effect of the 2006 US recommendation on influenza-related emergency department visits to Children’s Hospital Boston, with the Montreal Children’s Hospital as an untreated control.     

Vaccination Coverage and Compliance with Three Recommended Schedules of 10-Valent Pneumococcal Conjugate Vaccine during the First Year of Its Introduction in Brazil: A Cross-Sectional Study

Pneumococcal 10-valent conjugate vaccine (PCV10) was introduced to Brazil’s National Immunization Program (NIP) in 2010. During the first year of vaccine introduction three schedules were used to deal with age at initiation of PCV for catch-up purposes: 3 primary doses + 1 booster (for children aged ≤6 months), a catch-up schedule of 2 doses + 1 booster (7-11 months), and a catch-up schedule of a single dose (12-15 months). The purpose of this study was to assess the magnitude and associated risk factors for under-vaccination or lack of on time vaccination six to eight months after PCV10 introduction. A household survey was conducted in the municipality of Goiania with 1,237 children, who were retroactively classified into one of three age groups, as a factor of the child’s age relatively to 30 days after PCV10 introduction. Socioeconomic characteristics and vaccination dates were obtained during home interviews. Vaccination coverage was defined as the percentage of children who completed the recommended number of doses. Compliance with recommended schedules was defined as the percentage of children who received all valid doses at the NIP recommended time interval. Adjusted prevalence ratios (PR) of variables independently associated with coverage and compliance were estimated by log binomial regression. Coverage of DTP-Hib was used for comparison purposes. Overall, vaccination coverage was 54.6% (95% CI 52.1-57.7%), lower than DTP-Hib coverage (93.0%; 95% CI 91.5-94.3%). Compliance with recommended schedules was 16.8% (95% CI: 14.7-18.6%). Children 7-11 months old had lower coverage (40.7%) and compliance (6.3%) compared to children aged 12-15 months (coverage: 88.8%; compliance: 35.6%) and ≤6 months old (coverage: 54%; compliance: 18.8%). Having private health insurance was associated with higher PCV10 coverage (PR=1.25; 95% CI: 1.06-1.47, p=0.007), and compliance (PR=1.09; 95% CI: 1.02-1.16, p=0.015). Although PCV10 coverage rapidly increased shortly after vaccination introduction, it was not matched by compliance with recommended schedules. Public initiatives should target compliance of PCV10 because of the burden of pneumococcal diseases on childhood morbidity and mortality.     

Recurring measles epidemic in Vietnam 2005-2009: implication for strengthened control strategies

Background: Measles remains a serious vaccine preventable cause of mortality in developing nations. Vietnam is aiming to achieve the level of immunity required to eliminate measles by maintaining a high coverage of routine first vaccinations in infants, routine second vaccinations at school entry and supplementary local campaigns in high-risk areas. Regular outbreaks of measles are reported, during 2005-2009.Methods: National measles case-based surveillance data collected during 2005-June 2009 was analyzed to assess the epidemiological trend and risk factors associated with measles outbreak in Vietnam.Results: Of the 36,282 measles suspected cases reported nationwide, only 7,086 cases were confirmed through laboratory examination. Although cyclical outbreaks occurred between 2005 and 2009, there was no definite trend in measles outbreaks during these periods. Overall, 2438 of measles confirmed cases were among children ≤5 years and 3068 cases were among people ≥16 years. The distribution with respect to gender skewed towards male (3667 cases) significant difference was not observed (P= 0.1693). Unsurprisingly, 4493 of the confirmed cases had no history of vaccination (X² <0.01). The northern and highland regions were identified as the main endemic foci and the spatial distribution changed with time. The occurrence of cases, in a considerable proportion of vaccinated population, is not only a reflection of the high vaccination coverage in Vietnam but also portrays a possibility of less than 100% vaccine efficacy. More so, in order to prevent measles in adults, high-risk groups must be identified and catch-up for selected groups selected.Conclusions: This study therefore reinforces the need for continued improvement of surveillance system and to probe into the possible role of changes in age-distribution of cases if the effective control of measles is to be achieved.     

Immunogenicity of a Recombinant Measles-HIV-1 Clade B Candidate Vaccine

Live attenuated measles virus is one of the most efficient and safest vaccines available, making it an attractive candidate vector for a HIV/AIDS vaccine aimed at eliciting cell-mediated immune responses (CMI). Here we have characterized the potency of CMI responses generated in mice and non-human primates after intramuscular immunisation with a candidate recombinant measles vaccine carrying an HIV-1 insert encoding Clade B Gag, RT and Nef (MV1-F4). Eight Mauritian derived, MHC-typed cynomolgus macaques were immunised with 10⁵ TCID₅₀ of MV1-F4, four of which were boosted 28 days later with the same vaccine. F4 and measles virus (MV)-specific cytokine producing T cell responses were detected in 6 and 7 out of 8 vaccinees, respectively. Vaccinees with either M6 or recombinant MHC haplotypes demonstrated the strongest cytokine responses to F4 peptides. Polyfunctional analysis revealed a pattern of TNFα and IL-2 responses by CD4+ T cells and TNFα and IFNγ responses by CD8+ T cells to F4 peptides. HIV-specific CD4+ and CD8+ T cells expressing cytokines waned in peripheral blood lymphocytes by day 84, but CD8+ T cell responses to F4 peptides could still be detected in lymphoid tissues more than 3 months after vaccination. Anti-F4 and anti-MV antibody responses were detected in 6 and 8 out of 8 vaccinees, respectively. Titres of anti-F4 and MV antibodies were boosted in vaccinees that received a second immunisation. MV1-F4 carrying HIV-1 Clade B inserts induces robust boostable immunity in non-human primates. These results support further exploration of the MV1-F4 vector modality in vaccination strategies that may limit HIV-1 infectivity.     

沪191麻疹疫苗免疫持久性和影响因素的评价

１９９１～１９９８年,我们对荆州区川店镇５０３名６～１５月龄儿童进行了现行沪１９１麻疹疫苗血清流行病学效果观察,结果表明,初次免疫后１个月麻疹ＩｇＧ抗体阳转率为９１６５％,ＧＭＴ为１∶２６６７４,达保护滴度者比例为４６５％。随着时间的推移,第４年上述指标迅速下降到４６８６％、１∶１２７４和１８５％,第６年时低至２９４３％、１∶４８９和１３６％。０２ｍｌ、０３ｍｌ和０５ｍｌ麻疹疫苗组的近期和远期效果是类似的,初免后１个月时ＩｇＧ滴度越高,其免疫持久性越好;初免月龄是影响麻苗免疫效果的主要原因,６月龄初免组的免疫效果明显低于≥８月龄组。结果提示麻苗８月龄初免是可行的。     

Primary immunisation and febrile convulsions in Oxford 1972-5.

A three-year study of febrile convulsions in Oxford with comprehensive notification from general practice and hospitals showed a 3% risk for all children of suffering at least one febrile convulsion by the age of 5 years. Children were most at risk between 6 and 27 months, and febrile convulsions were most likely to be prolonged in children aged 9-15 months. The association between febrile convulsions and primary immunisations in the preceding 28 days was compared in case and control children, matched for age and sex. Results suggested that such association was a chance relationship with age. If association was direct, the febrile convulsion rates per 1000 immunisation doses were estimated as follows: diphtheria, pertussis, tetanus--0-09 per 1000; poliomyelitis--0-6 per 1000; and measles--0-9 per 1000. Hence if any of these vaccines had a secific causal relationship with febrile convulsions, these rates would probably have been much higher.     

Vaccination against measles, mumps and rubella (MMR): a comparison between the antibody responses at the ages of 18 months and 12 years and between different methods of antibody titration

In connection with the introduction of the trivalent vaccine against measles, mumps and rubella at 18 months and 12 years of age, an evaluation of the seroconversion and booster effects in the two age-groups was carried out. This also comprised different laboratory-test methods appropriate for follow-up studies after large-scale, vaccination studies. The measles, mumps and rubella antibodies were measured by the haemolysis-in-gel (HIG) method. Measles antibodies were also measured by the haemagglutination-inhibition (HI) test. Borderline values or samples negative to measles or mumps were also tested by the serum-neutralization (SN) test. All but four of 150 18-month-old children lacked antibodies against measles by the HI test and one of these by the HIG method. Against mumps, 99% were seronegative in the HIG test and 97% in the SN test and two against rubella prior to vaccination. Among 247 schoolchildren, 60 (24%) lacked antibodies in the HI test and 28 (11%) of these also in the HIG test. Sixty-six schoolchildren (25%) were negative to mumps and 45% to rubella prior to vaccination. The seroconversion rate for the 18-month-old children was 96% against measles, 93% against mumps and 99% against rubella. The figure for the schoolchildren was 82% against measles, 80% against mumps and 100% against rubella. On comparing the titre levels in seroconverting children, the measles-antibody levels were found to be lower among older children, compared with younger, while the opposite was true for rubella.(ABSTRACT TRUNCATED AT 250 WORDS)