Measles infection in persons with secondary vaccine failure,New York City, 2018–19

A large measles outbreak in New York City, which included cases among vaccinated persons and adults presumed to be immune, provided the opportunity to better understand vaccine failure and the potential impact on measles transmission. Immunoglobulin G (IgG) avidity can distinguish primary (low avidity IgG, indicating no evidence of prior immunity) versus secondary vaccine failure (high avidity IgG, indicating prior immune response and waning antibody). Measles IgG avidity was measured on samples from 62 persons: avidity was high in 53 (16 vaccinated and 37 with unknown vaccination history) and low in 9 (1 recently vaccinated and 8 with unknown vaccination history). Secondary transmission from 2 persons with high-avidity IgG results occurred. These findings illustrate that in settings of sustained measles elimination, measles infection and transmission can occur in persons with secondary vaccine failure, underscoring the need to maintain a high index of suspicion for measles during an outbreak despite prior or presumed prior vaccination.     

A measles outbreak in a middle school with high vaccination coverage and evidence of prior immunity among cases,Beijing, P.R. China

BackgroundAge-appropriate receipt of ≥2 measles-containing vaccine (MCV) doses has been considered evidence of immunity against measles. Transmission of measles is rarely reported among such persons.MethodsWe report a measles outbreak in a middle school in Beijing that has high coverage with≥2 documented MCV doses. History of previous measles and documentation of MCV receipt were collected for all individuals. Cases were identified by active surveillance and confirmed by laboratory tests. Measles immunoglobulin G (IgG) titers and clinical presentations were obtained for each case.ResultsOf 1331 individuals without a prior history of measles, 1172 (88.1% [95%CI:86.4–91.5%]) and 1078 (81.0% [95%CI:78.9–83.1%]) had age-appropriate receipt of ≥2 MCV doses by domestic and U.S. CDC/ACIP criteria, respectively. Thirteen measles cases occurred in the outbreak. The index case and 3 secondary cases were students. The 9 tertiary cases included 2 teachers and 7 students. All 11 student cases received ≥2 age-appropriate MCV doses by Chinese domestic criteria; 8 were age-appropriately vaccinated by U.S. CDC/ACIP criteria. Measles IgG was detected during the acute phase of measles for all but 2 cases -the first case and 1 tertiary case. Among students with age-appropriate receipt of ≥2 MCV doses, the length of time since the last MCV was significantly associated with risk of measles: for the 1172 students, the risk was 4.6 [OR5.6;95%CI:1.4–22.9] and 5.5 [OR6.5;95%CI:1.4–29.8] times higher when the last MCV dose was 5–9 years and ≥10 years prior, respectively, compared with <5 years prior; for the 1078 students, the risk was 4.1 [OR5.1;95%CI:1.3–20.7] times higher when the last MCV dose was 5–9 years prior compared with <5 years prior.ConclusionsThis is the first report from China showing measles transmission among persons with prior evidence of immunity. Secondary vaccine failure may have played an important role in measles transmission. Further laboratory surveillance is needed to assess the persistence of vaccine-induced immunity of domestically-produced MCV in China.     

Long-term antibody response after measles vaccination in an isolated arctic society in Greenland

Scoresbysund is an isolated district on the east coast of Greenland with 500 inhabitants, mainly Polar Eskimos, which had never been exposed to natural measles. In 1968 more than 90% of the population were vaccinated with the Schwarz live further-attenuated measles vaccine and subsequently children born after 1968 likewise received the measles vaccination. Upon the initial measles vaccination no clinical cases of measles have been observed. The immunity status of the isolated population has been followed for 16 years after vaccination by IgM, IgA, and IgG ELISA tests and by HI test on a series of serum samples taken at intervals. Immunoblotting was performed on sera obtained 16 years after the vaccination. In general, antibody studies have demonstrated some decline in antibody titres after the initial measles vaccination. However, a temporary moderate increase in measles antibodies occurred in some individuals 2-4 years after vaccination, probably due to a reinfection of vaccinees. Most of these individuals did not have demonstrable IgA antibodies prior to the supposed reinfection.     

Seroprevalence of measles,mumps and rubella among children in American Samoa, 2011, and progress towards West Pacific Region goals of elimination

Introduction

In line with the global goals for measles elimination, countries in the West Pacific Region (WPR) have set a goal to eliminate measles by 2012. Due to its contagiousness, high population immunity is needed for achieving and documenting measles elimination. We assessed population immunity to measles, mumps and rubella among first grade children in American Samoa (AS) through a seroprevalance study.

Methods

Using commercial indirect enzyme-linked immunosorbant IgG assays (Wampole Laboratories, Cranbury, NJ) we determined IgG antibodies against the measles, mumps, and rubella (MMR) viruses in sera collected from first grade students in AS in April–May 2011. Vaccination status was retrieved from the immunization cards. Factors associated with seropositivity of measles, mumps, and rubella were analyzed separately.

Result

Among 509 first grade students, measles, mumps, and rubella seroprevalence were 92%, 90%, and 93%, respectively. The proportions of first grade students with documented one or two doses of MMR vaccine were 93% and 84%, respectively. The vaccination status of 6% of the first graders was unknown and 1% was unvaccinated. Receiving two-doses of MMR vaccines was associated with high measles and mumps seropositivity (p < 0.01).

Conclusion

The high measles seroprevalence among children shows the progress by American Samoa towards measles elimination. Achieving and maintaining high two-dose MMR vaccine coverage in all age groups will aid in attaining the measles elimination status and prevent transmission of measles from potential imported measles cases from other countries.     

Antibody persistence in young adults 1 year after MMR immunization by aerosol or by subcutaneous route

Information on antibody persistence after aerosol revaccination with MMR components is limited. Thus, antibody titers were determined in 283 adult participants in a MMR vaccine trial 12 months after revaccination. One group had received aerosolized Triviraten vaccine while two other groups received either injected Triviraten or MMR II vaccine. Both MMR vaccines contained the same rubella strain, but different measles and mumps strains. Seropositivity to measles persisted in 98% of aerosolized vaccine recipients, 92% of injected Triviraten, and 95% of injected MMR II. All participants in the three groups retained seropositivity to rubella, while less than 50% remained seropositive to mumps.     

Measles outbreak in a vaccinated school population: epidemiology, chains of transmission and the role of vaccine failures

An outbreak of measles occurred in a high school with a documented vaccination level of 98 per cent. Nineteen (70 per cent) of the cases were students who had histories of measles vaccination at 12 months of age or older and are therefore considered vaccine failures. Persons who were unimmunized or immunized at less than 12 months of age had substantially higher attack rates compared to those immunized on or after 12 months of age. Vaccine failures among apparently adequately vaccinated individuals were sources of infection for at least 48 per cent of the cases in the outbreak. There was no evidence to suggest that waning immunity was a contributing factor among the vaccine failures. Close contact with cases of measles in the high school, source or provider of vaccine, sharing common activities or classes with cases, and verification of the vaccination history were not significant risk factors in the outbreak. The outbreak subsided spontaneously after four generations of illness in the school and demonstrates that when measles is introduced in a highly vaccinated population, vaccine failures may play some role in transmission but that such transmission is not usually sustained.     

Inadequate immunity to measles in children vaccinated at an early age: effect of revaccination

This report describes a follow-up serological study of 79 Brazilian children who, because of their young age, had failed to develop protective levels of immunity after vaccination against measles. There was serological evidence that infection with wild virus had occurred at a rate of about 17% per annum. Approximately 1½ years after the initial vaccination, 46% of the uninfected children maintained very low levels of neutralizing antibody, but did not have a measurable haemagglutination-inhibition titre. Revaccination did not elicit an IgM response in most children, but stimulated anti-measles IgG production in all of them. In 36% of the children, the IgG titres fell again within three months to levels that may permit reinfection. If it is assumed that some of the persistent titres can be attributed to wild virus infection, the actual effect of revaccination would have been to immunize no more than 60% of the susceptible group. The results suggest that early administration of measles vaccine may produce a cohort of children with inadequate immunity who cannot be fully immunized by revaccination. The implications of these findings for measles immunization programmes are discussed.     

A school-based measles outbreak: the effect of a selective revaccination policy and risk factors for vaccine failure

Persons who received measles vaccine between 12 and 14 months of age have been found to be at increased risk of measles compared with those vaccinated at greater than or equal to 15 months of age. Because of this, in 1987 the Immunization Practices Advisory Committee of the US Public Health Service recommended that, during measles outbreaks, revaccination of persons vaccinated at 12-14 months of age be considered. During a school-based outbreak in New Mexico in 1987, the authors evaluated the effect of a mandatory revaccination policy in affected schools. Before the effect of revaccination, the overall attack rate in persons vaccinated at greater than or equal to 12 months of age was 4.1 cases/1,000 students; afterward, the risk was significantly reduced by 73%, to 1.1/1,000 students. The attack rate among students targeted for revaccination declined 100%, compared with 41% among those not revaccinated. Overall, attack rates were significantly lower in schools conducting revaccination early compared with schools holding later revaccination. In a retrospective cohort study of single-dose vaccines in one school, age at vaccination was not associated with risk of disease; however, persons vaccinated greater than or equal to 10 years before the outbreak were at increased risk, independently of age at vaccination. Revaccination of persons whose most recent vaccination was between 12 and 14 months of age appeared to control transmission in this outbreak. Further studies are needed to confirm these observations and to evaluate the effect of other revaccination efforts during outbreaks.     

无锡市新区外来成年人群麻疹免疫水平分析

目的了解无锡市新区成年外来人口麻疹抗体水平,为制定新区控制和消除麻疹的措施提供依据。方法随机抽取无锡市新区健康成年外来人群共计823人进行麻疹IgG抗体水平检测及相关问卷调查。结果调查非无锡本地户籍外来务工人员823名,血清麻疹抗体IgG阳性率仅为30．13％,保护性抗体阳性率为25．52％;抗体几何平均滴度为1：179,该类人群麻疹免疫水平远低于保护水平。结论无锡新区成年外来人群麻疹病毒免疫水平低下,在合适的条件下极易造成麻疹的流行或暴发。     

2011年北京市大兴区麻风疫苗基础免疫成功率监测结果

目的了解北京市大兴区2011年8月龄儿童接种麻疹风疹联合减毒活疫苗(简称麻风疫苗)后的免疫效果,为制定麻疹免疫策略提供依据。方法采集40名8月龄儿童麻风疫苗免疫前、免疫后1个月双份血标本,分别进行麻疹、风疹IgG抗体测定。结果免后麻疹抗体阳性40人,阳性率100%,GMT 1∶1 385.52;风疹抗体阳性33人,阳性率82.50%,GMT 1∶31.18。结论该区现行的麻风疫苗所包含的麻疹成分免疫原性好,风疹成分免疫效果较差,应进行风疹疫苗复种弥补。     

免疫接种后麻疹病例的流行病学特征及发病原因分析

目的了解西安市麻疹发病的实际情况,探讨接种麻疹疫苗(MV)后病例的流行病学特征和发病的主要原因。方法开展回顾性流行病学调查,并采集病例静脉血3~5ml,进行麻疹IgM复核和IgG检测。结果西安市2004年12月麻疹病例较近年同期明显增多,而且病例中流动、常住人口分别占45.1%、54.9%;免疫后的流动、常住人口病例在发病年龄上无差异;免疫后病例与未免疫、免疫史不详病例的流行病学特征无差异,但抗体几何平均滴度免疫后高于未免疫者;麻疹发病的主要原因为免疫空白,接种技术、使用剂量、疫苗储运等因素也是引起发病的原因之一。结论做好MV的初种是控制麻疹发病的关键;变更MV免疫程序,将复种年龄提前到18~24月龄、接种剂量增加到0.5ml是必要的技术措施。     

Outbreak of measles in medical students and determination of immune status to measles-mumps-rubella viruses

We conducted an investigation after a measles outbreak in medical students to determine the immunity of the medical students, the correlation between history and seropositivity, and measles-mumps-rubella vaccine effectiveness. After a preliminary study done during measles outbreak, a cross-sectional study was planned. Serum samples from 322 medical students were tested by enzyme-linked immunosorbent assay, vaccinated volunteers, then re-tested vaccinees. Histories of measles, mumps and rubella were taken. Of 322 students, seven students (2.2%) were seronegative to measles, 13 (4.0%) to mumps, and 13 (4.0%) to rubella. Historical information revealed 30.4% of sensitivity in measles and 34.3% in mumps, whereas 5.2% in rubella. Among those seronegative on admission and vaccinated, seroconversion rates were 100% (5/5), 90.9% (10/11), 100% (8/8) in measles, mumps and rubella vaccine, respectively. Of 265 vaccinated students parotitis was detected in one female student, arthralgia was observed in three students (1.1%) and myalgia in two (0.7%), and 240 students reported no side effects. We detected the unreliable historical screening and high seroprevalence of measles, mumps and rubella in prevaccine era for mumps and rubella and, safety of MMR vaccination in medical students in Turkey.     

A measles outbreak at a college with a prematriculation immunization requirement.

BACKGROUND. In early 1988 an outbreak of 84 measles cases occurred at a college in Colorado in which over 98 percent of students had documentation of adequate measles immunity (physician diagnosed measles, receipt of live measles vaccine on or after the first birthday, or serologic evidence of immunity) due to an immunization requirement in effect since 1986. METHODS. To examine potential risk factors for measles vaccine failure, we conducted a retrospective cohort study among students living in campus dormitories using student health service vaccination records. RESULTS. Overall, 70 (83 percent) cases had been vaccinated at greater than or equal to 12 months of age. Students living in campus dormitories were at increased risk for measles compared to students living off-campus (RR = 3.0, 95% CI = 2.0, 4.7). Students vaccinated at 12-14 months of age were at increased risk compared to those vaccinated at greater than or equal to 15 months (RR = 3.1, 95% CI = 1.7, 5.7). Time since vaccination was not a risk factor for vaccine failure. Measles vaccine effectiveness was calculated to be 94% (95% CI = 86, 98) for vaccination at greater than or equal to 15 months. CONCLUSIONS. As in secondary schools, measles outbreaks can occur among highly vaccinated college populations. Implementation of recent recommendations to require two doses of measles vaccine for college entrants should help reduce measles outbreaks in college populations.     

A measles outbreak from an index case with immunologically confirmed secondary vaccine failure

During the elimination stage of measles, the development of such disease in individuals who received measles-containing vaccine (MCV) is a concern from an epidemiological standpoint. A few cases in which measles was transmitted from a patient who received two doses of MCV have been reported. However, whether such transmissions were caused by primary vaccine failure (PVF) or secondary vaccine failure (SVF) remains unclear. All patients suspected of measles in Osaka Prefecture between November and December 2018 were enrolled. Data about age, gender, immunization record, and clinical signs were obtained. Laboratory examinations were performed, which included virus isolation in tissue culture, a nucleic acid test based on virus-specific real-time polymerase chain reaction and humoral responses to the measles virus measuring immunoglobulin (Ig) M, IgG, avidity of IgG, and neutralizing antibody concentration. The measles outbreak comprised 10 laboratory confirmed cases, including three secondary and six tertiary patients. Among them, three secondary patients were unvaccinated. The index case had received two MCV doses, and the six tertiary patients were vaccinated. Both the index and tertiary patients had high specific IgG concentration with high avidity. In particular, the index patient had a markedly high neutralization antibody concentration of 425,590 mIU/mL, which indicated immunological SVF. This study first reported about measles transmission from an individual with SVF who received two vaccination doses. To prevent measles transmission and outbreak particularly in countries where measles was almost eliminated, patients with SVF for measles should be cautiously monitored.     

2009-2012年呼和浩特市健康人群麻疹IgG抗体水平调查

目的了解呼和浩特市2009-2012年健康人群麻疹的免疫状况,为降低麻疹发病率、提高人群免疫力提供依据。方法随机抽取呼和浩特市辖区内2009年新城区、和林县、托克托县、回民区4个监测点;2010年玉泉区、土默特左旗、武川县3个监测点;2011年新城区、和林县、托克托县、回民区4个监测点;2012年清水河、赛罕区、土默特左旗、玉泉区4个监测点,共1 125份人血清,采用酶联免疫法(ELISA)检测麻疹IgG抗体。结果共检测1 125份血清,麻疹IgG抗体阳性1 026份,抗体阳性率为91.2%,从年龄、年份、性别三方面进行比较,麻疹IgG抗体阳性率在年龄、性别、年份分布上均有统计学意义。结论麻疹IgG抗体阳性率达到较高的水平。目前在呼和浩特地区不可能出现大范围的麻疹爆发。     

宁波市人群麻疹免疫屏障的形成与作用探讨

为了解宁波市人群麻疹免疫屏障形成情况 ,对麻疹的发病情况、麻疹疫苗 (MV)的报告接种率和免疫成功率、人群的免疫水平进行综合分析 ,结果显示 :宁波市麻疹的发病率呈逐年下降趋势 ,至 2 0世纪 90年代以来一直维持在 <5 /10万 ;1986年以来MV的报告接种率均 >95 % ,连续 6年的儿童MV初免成功率 ,除 2 0 0 1年为 94 34% ,其余均为 10 0 % ;人群麻疹血凝抑制 (HI)抗体总阳性率为 97 17%。从目前麻疹的免疫屏障情况分析 ,宁波市近几年不会发生麻疹大规模流行。     

91例成人麻疹血清流行病学研究

目的探讨浙江省成人麻疹病例增多的原因。方法对4起麻疹流行中的91例成人患者,采集急性期和恢复期双份血清,检测麻疹血凝抑制抗体,用酶联免疫吸附试验测定IgG、IgM抗体。结果91例患者被确认为麻疹病例,发病年龄高峰在15~30岁。同时以急性期、恢复期IgMI、gG抗体的分布为标识进行分类,推算出91例患者中,麻疹减毒活疫苗(MV)原发性免疫失败或未免疫者为71例,占患者总数的78.0%;继发性免疫失败者为20人,占患者总数的22.0%。MV未免疫与原发性免疫失败病例中,有87.3%为未免疫或接种史不详。结论对不同人群应采取针对性的免疫措施与方案,以建立与完善人群的麻疹免疫屏障。     

Measles and rubella immunity in the population of Bhutan, 2017

BackgroundIn 2017, measles elimination was verified in Bhutan, and the country appears to have sufficiently high vaccination coverage to achieve rubella elimination. However, a measles and rubella serosurvey was conducted to find if any hidden immunity gaps existed that could threaten Bhutan’s elimination status.MethodsA nationwide, three-stage, cluster seroprevalence survey was conducted among individuals aged 1–4, 5–17, and >20 years in 2017. Demographic information and children’s vaccination history were collected, and a blood specimen was drawn. Serum was tested for measles and rubella immunoglobulin G (IgG). Frequencies, weighted proportions, and prevalence ratios for measles and rubella seropositivity were calculated by demographic and vaccination history, taking into account the study design.ResultsOf the 1325 individuals tested, 1045 (81%, 95% CI 78%–85%) were measles IgG seropositive, and 1290 (97%, 95% CI 95%–99%) were rubella IgG seropositive. Rubella IgG seropositivity was high in all three age strata, but only 47% of those aged 5–17 years were measles IgG seropositive. Additionally, only 41% of those aged 5–17 years who had documented receipt of two doses of measles– or measles-rubella–containing vaccine were seropositive for measles IgG, but almost all these children were rubella IgG seropositive.ConclusionsAn unexpected measles immunity gap was identified among children 5–17 years of age. It is unclear why this immunity gap exists; however, it could have led to a large outbreak and threatened sustaining of measles elimination in Bhutan. Based on this finding, a mass vaccination campaign was conducted to close the immunity gap.     

Measles outbreak in the Republic of the Marshall Islands, 2003

BACKGROUND: Measles is a highly contagious viral infection. Measles transmission can be prevented through high population immunity (>or=95%) achieved by measles vaccination. In the Republic of the Marshall Islands (RMI), no measles cases were reported during 1989-2002; however, a large measles outbreak occurred in 2003. Reported 1-dose measles vaccine coverage among children aged 12-23 months varied widely (52-94%) between 1990 and 2000. METHODS: RMI is a Pacific island nation (1999 population: 50,840). A measles case was defined as fever, rash, and cough, or coryza, or conjunctivitis, in an RMI resident between July 13 and November 7, 2003. A vaccination campaign was used for outbreak control. RESULTS: Of the 826 reported measles cases, 766 (92%) occurred in the capital (Majuro). There were 186 (23%) cases in infants aged <1 year and 309 (37%) of cases in persons aged >or=15 years. The attack rate was highest among infants (Majuro atoll: 213 cases/1,000 infants). Among cases aged 1-14 years, 281 (59%) reported no measles vaccination before July 2003. There were 100 hospitalizations and 3 deaths. The measles H1 genotype was identified. The vaccination campaign resulted in 93% coverage among persons aged 6 months to 40 years. Interpretation Populations without endemic measles transmission can accumulate substantial susceptibility and be at risk for large outbreaks when measles virus is imported. 'Islands' of measles susceptibility may develop in infants, adults, and any groups with low vaccine coverage. To prevent outbreaks, high population immunity must be sustained by maintaining and documenting high vaccine coverage.     

Mumps outbreak and MMR IgG surveillance as a predictor for immunity in military trainees

In 2017, a mumps outbreak occurred in a barrack holding 249 service members. Suspected cases were evaluated with a combination of mumps IgG, IgM, viral culture, PCR and sequencing. Seven cases were diagnosed in febrile patients presenting with parotitis or orchitis. Mumps infection was confirmed by IgM or positive PCR with 5/7 cases having notable IgG levels before infection. Sequencing confirmed mumps genotype G strain. Serum from all 249 service members collected prior to the outbreak was withdrawn from the Department of Defense (DoD) Serum Repository and the IgG values of measles, mumps and rubella determined with 20.2%, 12.3% and 9.7% service members being seronegative, respectively. No specific IgG seronegativity combination predicted IgG marker levels to another virus within the same vaccine. This paper provides additional evidence that mumps serology is not a reliable surrogate for mumps immunity and that we need better laboratory correlates to confirm immunity.