Stop measles in Switzerland – The importance of travel medicine

BackgroundIn line with the worldwide strive to combat measles, the Swiss Federal Office of Public Heath (FOPH) launched a National Strategy for measles elimination 2011–2015. In this study, we highlight the importance of travel medicine consultations to complement measles vaccination programmes based on data from the Travel Clinic of the University of Zurich.MethodWe analysed measles vaccination data from the Zurich Travel Clinic between July 2010 and February 2016 and focused on three groups: (i) all clients who received the measles vaccination, (ii) all clients aged > two years who received the measles vaccination (“catch-up vaccination”), and (iii) all clients aged > two years and born after 1963 (“FOPH recommended catch-up vaccination”).Results107,669 consultations were performed from 2010 to 2016. In 12,470 (11.6%) of these, a measles vaccination was administered; 90.9% measles vaccinations were given during a pre-travel consultation, and 99.4% were administered to individuals aged > two years (“catch-up vaccinations”). An “FOPH recommended catch-up vaccination” was received by 13.6% of all Zurich Travel Clinic clients aged >2 years and born after 1963.ConclusionsIn this study, we highlight the importance of travel medicine consultations to enhance the measles vaccination coverage in the adult Swiss population.     

Seroepidemiology of measles in Catalonia (Spain) 1985–1986

A seroepidemiological study of measles immunological status was carried out among four different populations: schoolchildren of 6–7 years, 10–11 years and 13–14 years, and pregnant women of 18–45 years, in Catalonia, Spain; 1,213 children and 239 pregnant women were surveyed. The measurement of measles antibodies was made by indirect immunofluorescence, with antibody titres 1:8 considered as positive.The prevalence of measles antibodies was 82.9% in the 6–7 year old group, 87.2%, in the 10–11 year old group and 94.4% in the age group 13–14 years. Among pregnant women, the prevalence of antibodies was 96.2%.Two of the variables studied were associated with the prevalence of measles antibodies in schoolchildren: the disease antecedents and measles vaccination. In pregnant women aged 18–45 no variable had any stastically significant association with the prevalence of measles antibodies.     

Increased measles–mumps–rubella (MMR) vaccine uptake in the context of a targeted immunisation campaign during a measles outbreak in a vaccine-reluctant community in England

Background

Following a measles outbreak in a vaccine-rejecting community between April and September 2011 in South-East England, local health agencies implemented a two-pronged measles–mumps–rubella (MMR) immunisation campaign from August to October offered at the local general practice where most cases were registered. The campaign included (a) accelerated vaccination of children earlier than scheduled (1st dose at 6–11 months, or 2nd dose at 18–39 months), (b) catch-up of those aged over 18 months who had had no MMR immunisations or were late for second MMR. We investigated the impact of the outbreak and campaign on the number of MMR doses given.

Materials and methods

In January 2012, we collected information on MMR vaccination for children registered at the practice aged 6 months–16 years on 1 August 2011, through the child health information system. We counted the number of MMR doses administered in 2011 and compared it to 2008–2010 data. We estimated the proportion vaccinated among the children eligible for the accelerated and catch-up campaign.

Results

The local practice administered 257 MMR doses in 2011, a 114% increase on the average for 2008–2010. Among children eligible for earlier MMR vaccination 5/26 (19%) received a first dose, and 34/57 (60%) a second dose. Among children eligible for catch-up, 20/329 (6%) received their first MMR and 39/121 (32%) their second. Of 1538 children, the proportion completely unimmunised for MMR declined by 3 percentage-points after the outbreak.

Discussion

Uptake of MMR vaccination significantly increased during the outbreak following the immunisation campaign. Those amenable to MMR vaccination seem to have benefited from the campaign more than those with no previous vaccinations. Future evaluations should address what made a few parents change their mind and have their children vaccinated for the first time during the outbreak.     

Immunogenicity of the AIK-C measles vaccine in infants aged <9 months in Vietnam

Measles-associated deaths have been reported in infants <9 months during outbreaks. A cohort study was conducted on 210 infants aged 6–8 months to evaluate the immunogenicity and safety of the AIK-C measles vaccine containing 10^4.21 plaque-forming units (PFU)/0.5 mL produced in Vietnam. Paired serum samples were obtained from 196 subjects. Seropositivity was defined as ≥120 mIU/mL. The seroresponse rate was 173/196 (88.27%, 95% confidence interval (CI): 83.77–92.77%) with geometric mean titer (GMT) of 511 mIU/mL (95% CI: 688–880 mIU/mL), and no significant differences were observed by different age groups. Among 196 paired sera, they were categorized into four groups: 122 subjects <14 IU/mL, 28 subjects 14–<60 mIU/mL, 30 subjects 60–<120 mIU/mL, and 16 subjects ≥ 120 mIU/mL. The seroresponse rate was 112/122 (91.8%, 95% CI: 86.94–96.67%) with GMT (597 mIU/mL, 95% CI: 749–1002 mIU/mL) in the <14 mIU/L group. In the 14–<60 mIU/mL group, the seroresponse rate was 18/28 (64.29%) with 184 mIU/L of GMT and was significantly lower (p < 0.01) than that in the <14 mIU/mL group. In the 16 seropositive group, all subjects showed seroconversion (4-fold higher than before) with a higher GMT of 1078 mIU/mL. Local pain and itching at the injection site were observed in 8 subjects (3.8%) within 7 days of the vaccination. Regarding systemic adverse reactions, febrile illness ≥37.5 °C was observed in 14 subjects (6.7%). These results indicate that the AIK-C measles vaccine is effective and safe for infants aged 6–8 months and will contribute to reducing the number of measles-associated deaths in future outbreaks.     

The epidemiology of measles in Tianjin,China, 2005–2014

BackgroundMeasles incidence in China has declined over the last decade and elimination is targeted by 2020. Despite increases in routine immunization services and supplementary immunization activities (SIAs), periodic outbreaks continue to occur. In this paper, we examine measles epidemiology during 2005–2014 in Tianjin, China.MethodsMeasles case data were extracted from a web-based communicable disease surveillance system. We examined the socio-demographic characteristics of measles case patients, including age, sex, urbanicity, residency status, and vaccination history. Demographic characteristics of cases were compared with the general population.ResultsFrom January 1, 2005 to December 31, 2014, 12,466 measles cases in Tianjin were reported. Among the cases, 7179 (57.6%) were male and 5287 (42.4%) were female. Over time, more cases occurred in adults, and for the 2711 cases in 2014, the majority were either infants <1 year (558, 20.58%) or adults ≥20 years (2043, 75.36%). Municipal-wide SIAs in Tianjin occurred in 2008 and 2010 with reduction in measles cases the following year for both (189 cases in 2009, and 37 cases in 2011). The number of cases rebounded to pre-SIA levels or higher within 1–3 years following each SIA: 1990 cases in 2010 and 2711 cases in 2014. Vaccination status was reported as “none” or “unknown” for 84% of all reported measles cases.ConclusionsDespite the general decline in cases, measles outbreaks continue to occur. Although the SIAs reduce numbers in their immediate aftermath, case counts rebound 1–3 years after the intervention. Continued monitoring of cases through disease surveillance activities accompanied by targeted immunization activities, including to adults, can help ensure progress toward elimination.     

Risk factors for measles in children aged 8 months–14 years in China after nationwide measles campaign: A multi-site case-control study, 2012–2013

IntroductionEndemic measles persists in China, despite >95% reported coverage of two measles-containing vaccine doses and nationwide campaign that vaccinated more than 100 million children in 2010. In 2011, almost half of the 9943 measles cases in China occurred in children eligible for measles vaccination. We conducted a case-control study during 2012–2013 to identify risk factors for measles infection in children aged 8 months–14 years.MethodsChildren with laboratory-confirmed measles were age- and neighborhood-matched with three controls. We interviewed parents of case and control infants on potential risk factors for measles. We calculated adjusted matched odds ratios and 95% confidence intervals of risk factors. We calculated attributable fractions for risk factors that could be interpreted as causal and vaccine efficacy (VE) for the measles containing vaccine (MCV) used in the Chinese immunization program.ResultsIn all, 969 case-patients and 2845 controls were enrolled. In multivariable analysis, lack of measles vaccination both overall (mOR 22.7 [16.6, 31.1] and when stratified by region (east region, mOR 74.2 [27.3, 202]; central/western regions mOR 17.4 [12.5, 24.3]), hospital exposure (mOR 63.0, 95% CI [32.8, 121]), and migration among counties (overall mOR 3.0 [2.3, 3.9]) were significant risk factors. The calculated VE was 91.9–96.1% for a single dose of MCV and 96.6–99.5% for 2 doses.ConclusionsLack of vaccination was the leading risk factor for measles infection, especially in children born since the 2010 supplementary immunization activity. Reducing missed vaccination opportunities, improving immunization access for migrant children, and strengthening school/kindergarten vaccine checks are needed to strengthen the routine immunization program and maintain progress toward measles elimination in China.     

Evaluation of measles–rubella vaccination for mothers in early puerperal phase

BackgroundThe postpartum period is an ideal opportunity to vaccinate mothers with inadequate immunity to vaccine-preventable diseases including measles and rubella.MethodsA prospective study of measles–rubella (MR) vaccination in the early puerperal phase was conducted in 171 mothers, who had insufficient antibody titers when screened for immunity to measles (≤1:4 on the neutralization test [NT]) or rubella (≤1:16 on the hemagglutination inhibition [HI] test) during pregnancy. To evaluate the efficacy of MR vaccination in the postpartum period, we determined their post-vaccination antibody titers and immune responses to vaccination, and investigated the association between these and their prolactin (PRL) levels and Th1/Th2 ratios at the time of vaccination. We also examined the passage of viral RNA and antigen into breast milk.ResultsOf the 169 participants who completed the study schedule, 117 and 101 had low antibody titers against measles and rubella, respectively. In the measles-seronegative group, the antibody-positive rate was 87% on the NT assay, and the NT geometric mean antibody titer was 11.4 (95% confidence interval [CI], 10.0–13.0). In the rubella-seronegative group, the antibody-positive rate was 88% on the HI test assay, and the HI geometric mean antibody titer was 64.0 (95% CI, 53.9–76.0). There was no association between the post-vaccination antibody titers and the PRL levels or Th1/Th2 ratios at the time of vaccination. In the rubella-seronegative group, subjects with higher Th1/Th2 ratios showed higher rates of responsiveness than those with lower ratios (P = 0.045). Although measles virus RNA was isolated from the breast milk of two vaccinated mothers, breastfeeding was not associated with clinical disease in any infants.ConclusionMR vaccination in the early puerperal phase is considered an effective way to prevent the diseases, regardless of the mother's immunological status and hormonal milieu.     

Declining measles antibodies in the era of elimination: Australia’s experience

BackgroundAustralia is one of only a few countries with a long-standing and consistent serosurveillance program. We conducted a national serosurvey in 2012–2013 to estimate population seroprevalence of measles-specific IgG and the effective reproduction number, R, and compare the results with the three previous serosurveys (1996–1999, 2002 and 2007) to examine trends following a decade of sustained measles control.Methods2729 residual sera from 1 to 49 year olds were tested using the Enzygnost anti-measles IgG enzyme immunoassay (EIA). All sera in the equivocal range by EIA on re-testing and a random sample of low positive and negative sera were later tested by a microneutralisation assay. R was calculated from weighted estimates of the proportion seronegative by age using a previously developed contact matrix.ResultsIn the 2012–13 serosurvey, anti-measles IgG seropositivity for 1–49 year olds was 80.8% (95% CI: 79.4–82.3%) and 8.9% (95% CI: 7.8–10.0%) had equivocal antibody levels. The increasing proportion of seronegative and equivocal individuals in age groups 10–39 years continued a trend seen in previous serosurveys. There was also an increase in equivocal results among 2–4 and 5–9 year old children, >90% of whom were recently vaccinated. R increased from 0.57 in 1999 to above the epidemic threshold of 1 in 2012–13 (R = 1.7). All 20 EIA negative sera, 238/241 (98.8%) equivocal sera, and 89/92 (96.7%) low positive sera had a titre <10 (negative) in the measles microneutralisation assay.ConclusionsA number of countries with sustained measles control have now demonstrated that measles-specific IgG antibodies decline with time since vaccination. As there is good epidemiologic evidence of population-level protection, the implications of declining measles-specific IgG antibody levels for maintaining measles elimination are unclear. Novel studies to determine correlates of protection against measles transmission and disease in the post-elimination era are needed to help answer this question.     

Measles in the United Kingdom 1990–2008 and the effectiveness of measles vaccines

We identified all children in the UK General Practice Research Database diagnosed with measles from 1990 to 2008 and calculated annual incidence according to age and geographic region by dividing the number of cases per year by the number of children who were active in the population. We evaluated the effectiveness of the measles vaccines by comparing the vaccination histories of children who were diagnosed with measles (cases) to children who were not (controls). The annual incidence of measles fell after the introduction of the MMR vaccine in late 1988. However, a modest outbreak of measles occurred in 1994, leading to large nationwide programs to immunize children. Since 1996, the incidence of measles has fallen by more than 80%. Prior measles vaccination is highly effective and has substantially reduced the risk of measles.     

Can measles be eradicated globally?

Measles is one of the most infectious diseases. Before measles vaccine was introduced, nearly everyone contracted the disease at some point in childhood. By the late 1980s, most countries had incorporated measles vaccine into their routine immunization programmes. Globally, about 800 000 children nevertheless still die from measles annually, half of them in Africa. Eradicating measles would therefore play an important role in improving children's survival. The 24th Pan American Sanitary Conference in 1994 established a goal of eradicating measles from the Americas. Progress to date has been remarkable and the disease is no longer endemic in the Americas, with most countries having documented interruption of transmission. As of November 2003, 12 months had elapsed since the last indigenous case was detected in Venezuela. This experience shows that measles transmission can be interrupted, and that this can be sustained over a long period of time. Global eradication is feasible if an appropriate strategy is implemented. Even under a new paradigm in which immunization is not discontinued after measles is eradicated, eradication will be a good investment to avoid expensive epidemics and save the lives of almost one million children annually. A world free of measles by 2015 is not a dream.     

Risk factors for measles infection in 0–7 month old children in China after the 2010 nationwide measles campaign: A multi-site case–control study, 2012–2013

IntroductionEndemic measles persists in China, despite >95% reported coverage of two measles-containing vaccine doses and nationwide campaign that vaccinated more than 100 million children in 2010. We performed a case–control study in six Chinese provinces during January 2012 through June 2013 to identify risk factors for measles infection among children aged 0–7 months.MethodsChildren with laboratory-confirmed measles were neighborhood matched with three controls. We interviewed parents of case and control infants on potential risk factors for measles. Adjusted matched odds ratios (mOR) and 95% confidence intervals (CIs) were calculated by multivariable conditional logistic modeling. We calculated attributable fractions for risk factors that could be interpreted as causal.ResultsEight hundred thirty cases and 2303 controls were enrolled. In multivariable analysis, male sex (mOR 1.6 [1.3, 2.0]), age 5–7 months (mOR 3.9 [3.0, 5.1]), migration between counties (mOR 2.3 [1.6, 3.4]), outpatient hospital visits (mOR 9.4 [6.6, 13.3]) and inpatient hospitalization (mOR 107.1 [48.8, 235.1]) were significant risk factors. The calculated attributable fractions for hospital visits was 43.1% (95% CI: 40.1, 47.5%) adjusted for age, sex and migration.ConclusionsHospital visitation was the largest risk factor for measles infection in infants. Improved hospital infection control practices would accelerate measles elimination in China.     

Achieving better measles immunization in developing countries: does higher coverage imply lower inequality?

Changes in measles immunization are commonly expressed in terms of a change in mean coverage rates but these mean changes may conceal substantial disparities within societies by poverty status. This paper analyzes trends in both the level and the socio-economic distribution of measles immunization coverage in the 1990s for 21 developing countries with two rounds of Demographic and Health Surveys available. We examine these trends using "achievement" indices that combine trends in means and in inequality. We propose and employ "achievement contours" to illustrate graphically how a greater degree of societal aversion to inequality may affect the ranking of countries in terms of achieved measles immunization coverage. The results indicate that most countries have experienced an improvement in their mean measles immunization rate but that this improvement was often unequally distributed across wealth groups, disfavouring the poor in all countries. Mean improvements were found to be associated with both increasing and decreasing inequality. When the trend in the mean and in the degree of inequality was opposite, the trend in the overall "achievement" score is determined by the assumed underlying degree of inequality aversion. As such, the achievement measure "penalizes" coverage improvements that leave the poor lagging behind.     

Available studies fail to provide strong evidence of increased risk of diarrhea mortality due to measles in the period 4–26 weeks after measles rash onset

Background

Measles vaccination effectiveness studies showed dramatic decreases in all-cause mortality in excess of what would be expected from the prevention of measles disease alone. This invited speculation that measles infection may increase the risk of diarrhea morbidity and mortality subsequent to the acute phase of the disease. The aim of the present systematic review is to summarize the existing evidence in the publically available literature pertaining to the putative causal link between measles and diarrhea in the period 4–26 weeks following measles rash onset.

Methods

We searched the PubMed, Embase, Open Grey and Grey Literature Report databases for relevant literature using broad search terms. Prospective, retrospective and case-control studies in low- and middle-income countries involving children under five wherein relevant evidence were presented were included. Data were extracted from the articles and summarized.

Results

Fifty abstracts retrieved through the database searches met the initial screening criteria. Twelve additional documents were identified by review of the references of the documents found in the initial searches. Six documents representing five unique studies that presented evidence relevant to the research question were found. Four of the included studies took place in Bangladesh. One of the included studies took place in Sudan. Some measles vaccine effectiveness studies show lower diarrhea morbidity and mortality among the vaccinated. However, children who received vaccine may have differed in important ways from children who did not, such as health service utilization. Additionally, cohort studies following unvaccinated children showed no difference in diarrhea morbidity and mortality between cases and controls more than 4 weeks after measles rash onset. One study showed some evidence that severe measles may predispose children to gastroenteritis, but was not able to show a corresponding increase in the risk of diarrhea mortality.

Conclusions

The available evidence suggests that the risk of measles-associated diarrhea mortality is largely limited to the 5-week period 1 week prior to and 4 weeks after measles rash onset, and that there is no increased risk of diarrhea mortality in the longer-term caused by measles.

     

Predictors related to the occurrence of a measles epidemic in the city of S?o Paulo in 1997.

A matched case-control study was performed to identify risk factors for measles during an epidemic that occurred in 1997 in the city of S?o Paulo, in the Brazilian state of the same name. Measles cases from the city of S?o Paulo from 1 January 1997 to 15 August 1997 were included in the study. The criteria for case definition were age below 30 years, having received no measles vaccine 5-21 days before the onset of rash, and laboratory confirmation by IgM antibodies detection. From a bank of confirmed measles cases, 130 cases for each of five age ranges (under 1 year, 1-5 years, 6-20 years, 21-24 years, and 25-29 years) were picked at random according to a systematic criterion proportional to the number of cases in seven areas of the city. Data were collected through a home survey, and for each measles case studied two controls matched by age and place of residence were selected. The matched conditional logistic regression analysis for the potential risk factors from the univariate analysis showed that the best predictors for acquiring measles during the epidemic were: lack of measles vaccination, previous contact with a measles-like disease at home or on the job, having been born either outside the state of S?o Paulo or in a rural area, being employed, and spending time in a semiclosed institution, such as a nursery, day care center, or school. The risk factors were not homogeneous for the different age groups. The data in the present survey suggest that, in addition to lack of vaccination, other risk factors should be considered when planning a measles vaccination strategy for a developing country.     

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?

OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.     

Description of a large measles epidemic in Democratic Republic of Congo, 2010–2013

Background

Although measles mortality has declined dramatically in Sub-Saharan Africa, measles remains a major public health problem in countries like the Democratic Republic of Congo (DRC). Here, we describe the large measles epidemic that occurred in the Democratic Republic of Congo between 2010 and 2013 using data from the national surveillance system as well as vaccine coverage surveys to provide a snapshot of the epidemiology of measles in DRC.

Methods

Standardized national surveillance data were used to describe measles cases from 2010 to 2013. Attack rates and case fatality ratios were calculated and the temporal and spatial evolution of the epidemic described. Data on laboratory confirmation and vaccination coverage surveys as a part of routine program monitoring are also presented.

Findings

Between week 1 of 2010 and week 45 of 2013, a total of 294,455 cases and 5,045 deaths were reported. The cumulative attack rate (AR) was 0.4%. The Case Fatality Ratio (CFR) was 1.7% among cases reported in health structures through national surveillance. A total of 186,178 cases (63%) were under 5 years old, representing an estimated AR of 1.4% in this age group. Following the first mass vaccination campaigns, weekly reported cases decreased by 21.5%. Results of post-vaccination campaign coverage surveys indicated sub-optimal (under 95%) vaccination coverage among children surveyed.

Conclusions

The data reported here highlight the need to seek additional means to reinforce routine immunization as well as ensure the timely implementation of Supplementary Immunization Activities to prevent large and repeated measles epidemics in DRC. Although reactive campaigns were conducted in response to the epidemic, strategies to ensure that children are vaccinated in the routine system remains the foundation of measles control.

     

Are refugees arriving in Denmark an under-immunised group for measles? A cross-sectional serology study

BackgroundIn 2018, Europe faced the highest number of Measles cases in a decade. In Denmark, the childhood vaccination programme has a coverage of approximately 90%. To eliminate the disease, vaccine coverage needs to be above the herd immunity threshold of 95%. This can be even more difficult to obtain, when vaccination programmes break down due to war, natural disasters etc. and concern has been raised, that unvaccinated refugees could facilitate spread of measles when migrating.MethodsIn order to address this concern, we tested 513 newly arrived refugees and family reunified refugees aged between 0 and 70 years for measles IgG antibodies. The participants were tested as part of a general health assessment between May 2016 and October 2018. In the cohort, 50% were males and the majority came from Syria (55%).ResultsWe found that 85% of the total group of refugees had immunity against measles. The 15% lacking antibodies were evenly distributed between the various countries of origin. Moreover, we found immunity to increase with age, leaving young children most vulnerable to infection, 79.9% (<19 years) vs 89.1% (≥19 years). Interview questions on previous vaccinations did not correlate to serology.ConclusionRefugees have measles immunity slightly lower than the host population.     

Are measles,mumps and rubella a public health issue in young adults? Results from a seroprevalence survey in university students in Italy

Aims  

A survey was conducted amongst university students to assess their level of susceptibility to and knowledge about measles, mumps and rubella (MMR) and their prevention, and to find factors associated to their seropositivity for MMR viruses.     

Study on factors associated with seroprotection after measles vaccination in children of 6–14 years in Eastern China

Measles cases have occurred in individuals with histories of vaccination against the disease in Zhejiang Province, China. The purposes of this study were to determine the seroprevalence of immunoglobulin G (IgG) measles antibodies in vaccinated individuals, to explore the waning kinetics of measles antibody among children after receipt of a measles-containing vaccine, and to define high-risk groups in the population. A seroprevalence survey of measles antibody was conducted with 1900 randomly selected and age-stratified participants aged 6–14 years in Zhejiang province. In our study, seronegative persons accounted for 7.17% of study participants. A case-control study of participants who had received at least one dose of measles-containing vaccine was conducted, with 123 cases of immune failure and 1593 controls with immune success. Multivariate logistic regression analysis showed that age, and number of doses were the influencing factors for measles immunization failure. The older a participant (odds ratio [OR] = 1.164), the more likely that measles vaccine immunity failed. In addition, immune failure was more likely to occur after one dose of MCV than two doses (OR = 0.008) or three doses and more (OR = 0.047). In a univariate logistic regression analysis, we found that immune failure was more likely to occur with MCV vaccination beginning at 8 months than at 9–11 months (OR = 0.562) and the subjects whose registration residence was in other cities in Zhejiang province (OR = 3.527). However, these differences in seropositivity were not significant in the multivariate logistic regression analysis. The exponential regression equation of the attenuation model after measles immunization was y = 884.64e^−0.057x (R² = 0.0521, p < 0.001), and results showed that the measles geometric mean concentration of IgG antibodies was approximately 884.64 mIU/ml after the last MCV vaccination and decreased with time since last vaccination.