Measles Susceptibility Research Articles

Measles in Bolivia: A ‘honeymoon period’

BackgroundAlthough measles is a highly infectious disease, the live measles vaccine provides protection for over 20 years, and immunity may be lifelong. This study assessed measles seroprevalence in schoolchildren in the Cochabamba region of Bolivia. MethodsA seroepidemiological survey of measles immunity in 5–16-year-old schoolchildren (n=441) living in the Cochabamba region of Bolivia was performed in March and April of 2010. Representative regional samples of school children from 14 schools were obtained. A parent-administered questionnaire collected sociodemographic and socio-economic status, and serum samples were tested for measles antibodies using an enzyme-linked fluorescent antibody test. The measles prevalence and corresponding 95% confidence intervals (CI) were calculated. A descriptive and bivariate analysis was performed using the ANOVA or the Kruskal–Wallis test according to whether the data were distributed normally (Kolmogorov–Smirnov test p-value<0.05) plus the chi-square test or Fisher's exact test as needed. ResultsThe global seroprevalence of measles was 69.61% (95% CI 65.32–73.90) and was higher in adolescents (84.16%, 95% CI 77.04–91.28) and Spanish speakers (74.74%, 95% CI 68.56–80.92). The seroprevalence did not differ according to socio-economic status, living area, or number of family members in the household. ConclusionsThis study found a high prevalence of measles susceptibility in Bolivian children. Thus, herd immunity may not have been established, and some outbreak could occur. Authorities should redress this situation before endemic measles transmission occurs nationally and regionally, and there is an urgent need to conduct more seroprevalence studies in the region.

Sero-epidemiology of measles-specific IgG antibodies and predictive factors for low or missing titres in a German population-based cross-sectional study in children and adolescents (KiGGS)

In the European Region, measles elimination is now targeted to 2015. To measure progress towards elimination age-group specific susceptibility targets have been defined. Age-specific measles susceptibility in children and adolescents was evaluated in Germany. Taking into account a broad range of socio-demographic, health- and vaccination status related variables, populations for vaccination campaigns were identified. We analysed data from children aged 1-17 years in the representative German Health Interview and Examination Survey for Children and Adolescents (KiGGS). Measles immunoglobulin G antibodies were measured in 13,977 participants by enzyme immunoassay (ELISA). Bivariate and multivariate logistic regression analyses were used to determine parental and infant related factors associated with measles susceptibility. The overall prevalence of seronegativity in children tested for measles IgG aged 1-17 years was 10.0% (95% CI 9.4-10.7). The prevalence of seronegativity in the German population was below the WHO targets for measles elimination in children aged 2-9 year-olds but exceeded the target for 10-17 year-olds. Age differences in the level of seronegativity were found to be mainly due to differences in vaccination coverage. A higher level of susceptibility was observed if parents did not comply with the request to present the child's vaccination card. In vaccinated children, immigration, male gender, very young age at first vaccination and a longer time period since last vaccination were associated with a higher level of susceptibility. Further increase of the two-dose vaccination coverage is necessary in order to achieve the WHO targets. Catch up vaccination campaigns should focus on adolescents and immigrants.

Progress Toward Measles Elimination in the People's Republic of China, 2000–2009

In 2006, China set a goal of measles elimination by 2012. To describe progress toward this goal, we reviewed relevant policies and strategies and analyzed national data for 2000-2009. In response to implementation of these strategies, including increased routine measles vaccination coverage and province-specific supplementary immunization activities (SIAs), reported measles incidence decreased to a historically low level of 39.5 cases per million in 2009. A synchronized nationwide SIA was scheduled in 2010 to further decrease susceptibility to measles. However, reaching and maintaining measles elimination will require strong political commitment and efforts for strengthening surveillance, increasing 2-dose vaccine coverage to >95%, stricter enforcement of the requirement to check immunization status at school entry, and careful attention to measles susceptibility in those aged ≥15 years.

Measles susceptibility in children in Karachi, Pakistan

Measles, despite being vaccine preventable is still a major public health problem in many developing countries. We estimated the proportion of measles susceptible children in Karachi, the largest metropolitan city of Pakistan, one year after the nationwide measles supplementary immunization activity (SIA) of 2007–2008. Oral fluid specimens of 504 randomly selected children from Karachi, aged 12–59 months were collected to detect measles IgG antibodies. Measles antibodies were detected in only 55% children. The proportion of children whose families reported receiving a single or two doses of measles vaccine were 78% and 12% respectively. Only 3% of parents reported that their child received measles vaccine through the SIA. Among the reported single dose measles vaccine recipients, 58% had serologic immunity against measles while among the reported two dose measles vaccine recipients, 64% had evidence of measles immunity. Urgent strengthening of routine immunization services and high quality mass vaccination campaigns against measles are recommended to achieve measles elimination in Pakistan.

Authors’ reply. Spotlight on measles 2010: Measles in healthcare workers – vaccination should be revisited

Since the beginning of the outbreak in 2008 and through the national early warning system [3], the French Institute for Public Health Surveillance (InVS) received a total of 42 notifications of nosocomial transmission events (three in 2008, 10 in 2009 and 29 since January 2010). Among the notified events, 30 involved at least one HCW, and 44 of 61 cases (72%) were HCWs. Two of the three nosocomial transmission events in 2008 occurred in spite of a low prevalence of measles susceptibility in HCWs [4-7].

Effect of Maternal HIV Infection on Measles Susceptibility During Early Infancy: Implications for Optimizing Protection of the Infant

The measles virus was first isolated as the causative pathogen of measles approximately 50 years ago by John Enders and Thomas Peebles. Despite a safe and effective vaccine extant for nearly the same amount of time, control of measles nevertheless remains a challenge in developing countries. This article investigates the possible contribution of maternal HIV infection on measles susceptibility in infants. The current WHO position on measles vaccination in HIV-infected children recommends vaccinating asymptomatic HIV-infected infants as early as 6 months of age, followed with two additional doses at 9 and 18 months. This is rarely implemented due to logistical constraints related to early HIV diagnosis in infants and access to vaccines in low-resource settings. In addition, measles vaccine safety and immunogenicity in HIV-infected children are based on very low levels of scientific evidence. There are no specific recommendations for measles immunization of HIV-uninfected children born to HIV-infected mothers. We reviewed the available data on transplacental transfer of measles antibody and the influence of HIV, the findings of which suggest that consideration should be given to extending early measles immunization to all infants born to HIV-infected women.

Towards elimination: measles susceptivility in Australia and 17 European countries

To evaluate age-specific measles susceptibility in Australia and 17 European countries. As part of the European Sero-Epidemiology Network 2 (ESEN2), 18 countries collected large national serum banks between 1996 and 2004. These banks were tested for measles IgG and the results converted to a common unitage to enable valid intercountry comparisons. Historical vaccination and disease incidence data were also collected. Age-stratified population susceptibility levels were compared to WHO European Region targets for measles elimination of < 15% in those aged 2-4 years, < 10% in 5-9-year-olds and < 5% in older age groups. Seven countries (Czech Republic, Hungary, Luxembourg, Spain, Slovakia, Slovenia and Sweden) met or came very close to the elimination targets. Four countries (Australia, Israel, Lithuania and Malta) had susceptibility levels above WHO targets in some older age groups indicating possible gaps in protection. Seven countries (Belgium, Bulgaria, Cyprus, England and Wales, Ireland, Latvia and Romania) were deemed to be at risk of epidemics as a result of high susceptibility in children and also, in some cases, adults. Although all countries now implement a two-dose measles vaccination schedule, if the WHO European Region target of measles elimination by 2010 is to be achieved higher routine coverage as well as vaccination campaigns in some older age cohorts are needed in some countries. Without these improvements, continued measles transmission and outbreaks are expected in Europe.

Impact of adverse publicity on MMR vaccine uptake: a population based analysis of vaccine uptake records for one million children, born 1987–2004

. Friederichs, V., Cameron, J.C. &amp; Robertson, C. ( 2006 ) , 91 , 465 – 468 . Aims To determine the impact of adverse publicity on MMR uptake and measles susceptibility, including whether vaccination is delayed and the role of deprivation.Methods A population database for all Scotland containing immunization records for over one million children (n = 1 079 327) born 1987–2004 was analysed. MMR uptake was determined by birth cohort and deprivation category. ‘Final’ uptake (at approximately age 6 years) was predicted by linear regression by birth cohort. Measles susceptibility in 1998 and 2003 was determined by postcode sector and district for cohorts combined to construct nursery and primary school age groups.Results There is evidence of a slight rise in late uptake, but insufficient to compensate for underlying declines. Late vaccination continues to be associated with deprivation, while the most affluent tend to be vaccinated promptly, or not at all. Predicted figures for ‘final’ MMR1 uptake are over 90%, but under 95%. Measles susceptibility has increased significantly in nursery children, with an eightfold rise in the number of districts with greater than 20% susceptibility in this group (from 3 to 25).Conclusions Increased measles susceptibility in nursery children is concerning, particularly in the most vulnerable areas. These figures are likely to increase in the future, as MMR uptake has not yet returned to the previous higher level. Increased susceptibility levels can also be expected in primary schools in the future, as levels of late uptake are insufficient to compensate. Predicted figures for ‘final’ MMR1 uptake are under the herd immunity threshold and campaigns may be required to increase uptake among future primary school children.

Impact of adverse publicity on MMR vaccine uptake: a population based analysis of vaccine uptake records for one million children, born 1987–2004

Aims: To determine the impact of adverse publicity on MMR uptake and measles susceptibility, including whether vaccination is delayed and the role of deprivation. Methods: A population database for all...

Measles outbreak in the Republic of the Marshall Islands, 2003

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. 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. 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.

Rubella and measles seroprevalence among women of childbearing age, Argentina, 2002

To assess rubella and measles susceptibility among women of childbearing age we conducted a cross-sectional seroprevalence study in four cities and one rural area in Argentina. A convenience sample of women aged 15-49 years seeking care in public health-care institutions was selected (n=2804). Serum specimens were tested for rubella and measles IgG antibody titres. The overall susceptibility to rubella and measles was 8.8 and 12.5% respectively. Seroprevalence differences were found for both rubella (P<0.001) and measles (P=0.002) across sites. Rubella seroprevalence was higher in women aged >or=40 years than in younger women (P=0.04). Measles seroprevalence tended to increase with age (P<0.001). Approximately 15% of women aged 15-29 years were not immune to measles. No risk factors were associated with rubella seronegativity; however, age (P<0.001) and having less than four pregnancies (P<0.001) were factors associated with measles seronegativity. Our findings support the introduction of supplemental immunization activities targeting adolescents and young adults to prevent congenital rubella syndrome and measles outbreaks over time.

Prevalence of measles susceptibility among health care workers in a UK hospital. Does the UK need to introduce a measles policy for its health care workers?

First, to determine the prevalence of measles non-immunity in a group of health care workers (HCW), and secondly, to investigate what pre-employment screening for measles is carried out by NHS occupational health departments. Two hundred and eighteen HCWs with patient contact on the medical wards at Addenbrooke's hospital provided an oral fluid sample and answered a questionnaire. A postal survey of Association of National Health Occupational Physicians Society (ANHOPS) members was conducted to assess whether UK NHS Trusts identify measles non-immune individuals. Of the HCWs tested, 3.3% of were found to be non-immune to measles (both oral fluid and confirmatory serum sample were measles IgG negative). Less than one third of a sample of 80 NHS occupational health departments enquired about measles immunity. The prevalence of measles non-immune health care workers is low, but with a fall in uptake of MMR immunization and increased likelihood of measles outbreaks, it is important to identify these at-risk individuals. Serum testing is the most reliable method to use. Oral fluid testing and history of measles disease or vaccination are unreliable methods of identifying non-immune individuals. To achieve complete immunity, it is cost-effective to screen and then offer immunization. NHS trusts vary greatly in their measles policies for health care workers.

Measles seroprevalence in Izmir with special emphasis on measles vaccination policy for Turkey.

Measles outbreaks seem to occur every 2- to 3-year intervals in Turkey. However, sero-epidemiological studies are limited. Knowing the prevalence of measles susceptibility as measured either by serologic markers of immunity or surveys of vaccination coverage is an important tool to assess the risk for measles outbreaks. In order to determine the seroprevalence of measles antibodies among a 1 to 29-year-old population in Izmir (Turkey) and to develop the best vaccination policy for measles, a total of 600 people aged from 1 to 29 were selected for the study with cluster sampling. The information on sociodemographic characteristics, vaccination status and measles history was gathered for each participant. Measles-specific IgG antibodies were screened qualitatively by using microenzyme immune assay for 595 subjects. Of the 595 participants screened for the measles antibodies, 56 (9.4%) were seronegative. The proportion of the susceptible individuals in the age groups of 1-4, 5-9, 10-14, 15-19 and 20-29 was 20.0, 10.4, 6.0, 10.3 and 3.0%, respectively. The logistic regression analysis showed that none of the independent characteristics (sex, socioeconomic status, past measles history, vaccination status) with the exception of age group, was significantly associated with measles seronegativity. The optimal measles vaccination policy for Turkey may be to increase vaccination coverage above 90%, to conduct a catch-up campaign covering persons aged 1-19, regardless of previous vaccination status. Another factor to consider is to adopt a routine two-dose vaccination, giving the first dose at 12-15 months of age and the second dose at school entry.

New strategies for closing the gap of measles susceptibility in infants: towards vaccines compatible with current vaccination schedules

Peptides representing epitopes of the measles virus glycoproteins have been designed to induce neutralizing and protective antibodies. Those that escape recognition by passively acquired anti-whole virus antibodies could potentially be used as components of a ‘pre-vaccine’ that could be given during early childhood irrespective of persisting maternal antibodies. Unlike vaccines based on recombinant proteins, epitope-based vaccines can be designed to be compatible with a subsequent boost with the standard life attenuated vaccine. Although synthetic peptides may induce only short-term immunity they have the potential to close in young infants the gap of vulnerability until the standard live attenuated vaccine can be given at 9 or 15 months of age.

Rubella susceptibility predicts measles susceptibility: implications for postpartum immunization.

Measles and mumps antibody titers were measured in 262 pregnant women who were either positive (n=128) or negative (n=134) for rubella antibodies. Susceptibility to measles and mumps was detected in 4.6% (12/262) and 7.6% (14/184) of the women, respectively. Of the rubella-susceptible group, 8.2% were also measles susceptible, whereas only 0.8% of the rubella-immune women were measles susceptible. Susceptibility to mumps was evenly divided between rubella-susceptible (7.8%) and rubella-immune (7.4%) groups.

Comparison of a commercial ELISA kit and a neutralization assay for assessment of humoral immunity to measles virus

Efficient control of measles apparently requires reimmunization of susceptibles. The classic techniques used for estimation of measles susceptibility, neutralization and hemeagglutination inhibition, are neither convenient nor exactly comparable when carried out in different laboratories. We have compared a one-dilution commercial enzyme-linked immunosorbant assay (ELISA) to a classic neutralization test with respect to its ability to designate susceptibles as well as its ability to indicate post-reimmunization rises in measles antibody levels. A group of controls not deemed to require reimmunization was tested in parallel. The results indicate that the simple and standardized commercial assay may be able to substitute for the classic assays, which can only be carried out in specialized laboratories, when simple screening for persons with low levels of antibodies to measles or when evaluations of responses to (re)immunizations are required.

Measles susceptibility under one year of age and vaccination strategy

Measles susceptibility under one year of age and vaccination strategy

Evidence for a recent decrease in measles susceptibility among young American adults.

As part of an ongoing evaluation of US Army immunization policies, two serologic surveys were conducted at an army basic training center. Antibody status to measles, mumps, and rubella were determined by an ELISA in 969 soldiers in 1989 and 992 soldiers in 1990. Measles seronegativity rates, directly adjusted to the 15- to 24-year-old US population in 1980, decreased from 21.3% in 1989 to 12.5% in 1990 (P < .001). Decreases also were observed in mumps (16.2% to 14.7%) and rubella seronegativity rates (18.4% to 14.3%) from 1989 to 1990 but were not statistically significant. In subgroup analyses, significant decreases in measles seronegativity were observed in younger, white, male, and female cohorts. There is evidence that susceptibility among young adults had declined, although it remains unclear if this is due to increased immunization or exposure to natural disease.

Immunity to Measles Among Health Care Workers in France

To the Editor. —The Centers for Disease Control and Prevention editorial note1raises an important question concerning measles susceptibility in adults. It is pointed out that a reduction in measles susceptibility may have occurred through increased measles vaccination among preschool-aged children. Nevertheless, measles screening for health care workers in the United States revealed significant numbers of nonimmune hospital employees.2,3We studied measles immunity in hospital employees in Orleans, France, a country where vaccination coverage is much lower than that reported in the United States. During the first few months of 1993, 465 serum samples were tested by enzyme immunoassay for measles antibody (IgG). This represented 14% of the employees. Of these 465 employees, four were seronegative. Of those born before 1957, none (0%) tested seronegative, while four (2%) of those born in or after 1957 were seronegative. The number of nonimmune hospital employees was lower in France than

Measles Immunity in a Population of Healthcare Workers

To evaluate measles seroprevalence among cohorts of new employees and to evaluate vaccine responses of susceptible adult healthcare workers. New employees were screened for measles susceptibility as part of employee evaluations. Anti-IgG measles antibody tests were completed on 2,473 workers. Demographic, measles history, and measles vaccination information was collected using a short questionnaire. Susceptible workers were vaccinated and screened for vaccine responses following vaccination. Ninety-three workers (4%) were seronegative, and 56 (2%) were equivocal. Individuals in the youngest cohort (born after 1956) were significantly more likely to be susceptible than those in the middle cohort (born 1951 to 1956) and those in the oldest cohort (born before 1951) (P < 0.01). The middle cohort included eight (5%) of the 149 seronegative or equivocal workers. Among the members of the youngest cohort, those from the United States were more likely to be susceptible (P < 0.01) than those from outside the United States. Of the 106 vaccinated susceptible workers whose follow-up serologies were determined, 90 (85%) developed positive IgG serologies, six had equivocal results, and 10 were seronegative. Eleven of the 16 non- or hyporesponders were revaccinated and re-evaluated; nine developed low positive IgG antimeasles levels, one exhibited an equivocal response, and one failed to respond. A small but important proportion of healthcare workers are susceptible to measles. Whenever feasible, measles immunity programs for healthcare workers should include workers born before 1957. Of workers born after 1956, those from outside the United States are more likely to be immune than workers from inside the United States. Using the currently available vaccine, revaccination of initial non- or hyporesponders appears to be effective.