Measles epidemics and seroepidemiology of population in Wujin,Changzhou city,Jiangsu province,China 2015

The measles epidemic was rather severe in Wujin 2015, and a seroprevalence survey of measles antibody was conducted during June to September 2015 in Wjin district of Changzhou city. Blood samples were collected from community health population and convenient samples of residual blood from hospitals. Measles-specific IgG levels were measured by ELISA assay. A total of 122 measles cases were reported 2015 in Wujin district with an incidence of 8.31 per 100 000 populations. A large proportion of measles cases were adults ≥20 years (62.30%) and infants aged <18 months (28.69%). Floating population accounted for 68.57% of all cases. 1070 blood samples aged from 9 months to 49 years old were collected and the overall seroprevalence and geometric mean titer (GMT) of measles were 82.71% and 551.19 mIU/ml, respectively. Although the seroprevalence among children aged 9 months to 4 years was consistently over 90%, it began to decrease since 24 months, and till the age of ≥10 years, the seroprevalences were all <80%, however, the seroprevalence rised to above 80% in people over 40 years. There were no significant differences between the two blood sample sources in the level of seroprevalence and GMT. Also no significant differences were observed in the seroprevalence of measles and GMT levels between genders. The seroprevalence and GMT in people with measles vaccination were higher than those without measles vaccination or people whose measles vaccination are unknown (P < 0.001). Our study indicated that the adult measles cases have become a serious problem in Wujin district, which may mainly relate to the increasing size of the floating population with low measles vaccine coverage. The seroprevalence of measles decreased dramatically with increasing age since teenagers, which may mainly caused by waning vaccine-induced immunity. Therefore, it is necessary to strengthen measles vaccine in these people especially floating population.     

An increasing,potentially measles-susceptible population over time after vaccination in Korea

BackgroundIn Korea, measles occurs mainly in infants <12 months of age, who are unvaccinated. In addition, vaccine populations, including adolescents and young adults, can become infected though importation. Thus, the question arises whether the current level of herd immunity in Korea is now insufficient for protecting against measles infection.MethodsAge-specific measles seroprevalence was evaluated by performing enzyme immunoassays and plaque reduction-neutralization tests on 3050 subjects aged 0–50 years (birth cohort 1964–2014) and 480 subjects aged 2–30 years (birth cohort 1984–2012).ResultsThe overall seropositivity and measles antibody concentrations were 71.5% and 1366 mIU/mL, respectively. Progressive decline in antibody levels and seropositivity were observed over time after vaccination in infants, adolescents, and young adults. The accumulation of potentially susceptible individuals in the population was confirmed by comparing data from 2010 and 2014 seroprevalence surveys. The statistical correlation between measles incidence and measles seronegativity was determined.ConclusionsWaning levels of measles antibodies with increasing time post-vaccination suggests that measles susceptibility is potentially increasing in Korea. This trend may be related to limitations of vaccine-induced immunity in the absence of natural boosting by the wild virus, compared to naturally acquired immunity triggered by measles infection. This study provides an important view into the current measles herd immunity in Korea.     

Estimating the burden of rubella virus infection and congenital rubella syndrome through a rubella immunity assessment among pregnant women in the Democratic Republic of the Congo: Potential impact on vaccination policy

BackgroundRubella-containing vaccines (RCV) are not yet part of the Democratic Republic of the Congo’s (DRC) vaccination program; however RCV introduction is planned before 2020. Because documentation of DRC’s historical burden of rubella virus infection and congenital rubella syndrome (CRS) has been minimal, estimates of the burden of rubella virus infection and of CRS would help inform the country’s strategy for RCV introduction.MethodsA rubella antibody seroprevalence assessment was conducted using serum collected during 2008–2009 from 1605 pregnant women aged 15–46 years attending 7 antenatal care sites in 3 of DRC’s provinces. Estimates of age- and site-specific rubella antibody seroprevalence, population, and fertility rates were used in catalytic models to estimate the incidence of CRS per 100,000 live births and the number of CRS cases born in 2013 in DRC.ResultsOverall 84% (95% CI 82, 86) of the women tested were estimated to be rubella antibody seropositive. The association between age and estimated antibody seroprevalence, adjusting for study site, was not significant (p = 0.10). Differences in overall estimated seroprevalence by study site were observed indicating variation by geographical area (p ⩽ 0.03 for all). Estimated seroprevalence was similar for women declaring residence in urban (84%) versus rural (83%) settings (p = 0.67). In 2013 for DRC nationally, the estimated incidence of CRS was 69/100,000 live births (95% CI 0, 186), corresponding to 2886 infants (95% CI 342, 6395) born with CRS.ConclusionsIn the 3 provinces, rubella virus transmission is endemic, and most viral exposure and seroconversion occurs before age 15 years. However, approximately 10–20% of the women were susceptible to rubella virus infection and thus at risk for having an infant with CRS. This analysis can guide plans for introduction of RCV in DRC. Per World Health Organization recommendations, introduction of RCV should be accompanied by a campaign targeting all children 9 months to 14 years of age as well as vaccination of women of child bearing age through routine services.     

Mumps,measles and rubella vaccination in children with PFAPA syndrome

There is no published data regarding immunologic response to vaccinations in children with PFAPA syndrome (periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis). The aim of this study was to evaluate mumps, measles and rubella immunity in children with PFAPA. 31 children with PFAPA syndrome and 22 healthy children (control group – CG) were recruited to the study. All children were previously vaccinated with one dose of MMR vaccine according to the Polish obligatory vaccination schedule. The patients from both groups were evaluated for anti-measles, anti-mumps and anti-rubella IgG antibodies concentrations (ELISA tests; the reference values for protective antibody levels were 150 IU/L, 16 RU/L and 11 IU/ml respectively). The percentage of patients with protective antibodies levels was as follows: measles – 93.55% of PFAPA and 95.45% of CG patients (p = 0.77); mumps – 74.19% of PFAPA and 95.45% of CG patients (p = 0.02); rubella – 80.65% of PFAPA and 90.9% of CG patients (p = 0.30). Conclusions: Children with PFAPA syndrome present a good response to the measles and rubella component of the MMR vaccine, however immunity against mumps after one dose of MMR may not be sufficient. Further investigation concerning immunity against vaccine-preventable diseases and the safety of vaccinations in children with periodic fever syndromes is required.     

CHRONOVAC VOYAGEUR: A study of the immune response to yellow fever vaccine among infants previously immunized against measles

For administration of multiple live attenuated vaccines, the Advisory Committee on Immunization Practices recommends either simultaneous immunization or period of at least 28 days between vaccines, due to a possible reduction in the immune response to either vaccine.The main objective of this study was to compare the immune response to measles (alone or combined with mumps and rubella) and yellow fever vaccines among infants aged 6–24 months living in a yellow fever non-endemic country who had received measles and yellow fever vaccines before travelling to a yellow fever endemic area.Subjects and methods: A retrospective, multicenter case-control study was carried out in 7 travel clinics in the Paris area from February 1st 2011 to march 31, 2015. Cases were defined as infants immunized with the yellow fever vaccine and with the measles vaccine, either alone or in combination with mumps and rubella vaccine, with a period of 1–27 days between each immunization. For each case, two controls were matched based on sex and age: a first control group (control 1) was defined as infants having received the measles vaccine and the yellow fever vaccine simultaneously; a second control group (control 2) was defined as infants who had a period of more than 27 days between receiving the measles vaccine and yellow fever vaccine.The primary endpoint of the study was the percentage of infants with protective immunity against yellow fever, measured by the titer of neutralizing antibodies in a venous blood sample.Results: One hundred and thirty-one infants were included in the study (62 cases, 50 infants in control 1 and 19 infants in control 2). Of these, 127 (96%) were shown to have a protective titer of yellow fever antibodies. All 4 infants without a protective titer of yellow fever antibodies were part of control group 1.Discussion: The measles vaccine, alone or combined with mumps and rubella vaccines, appears to have no influence on humoral immune response to the yellow fever vaccine when administered between 1 and 27 days. The absence of protective antibodies against yellow fever was observed only among infants who received both vaccines simultaneously.Conclusion: These results may support a revision of current vaccination recommendations concerning the administration of these two live attenuated vaccines either on the same day or at least 28 days apart. Our findings show no statistically significant difference if the interval between both vaccines is more than 24 h, but the immune response seems to be reduced when the two vaccines are given at the same time.     

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.     

Influences on immunization rates: Vaccination coverage of mumps,measles, rubella and varicella before and after the STIKO intervention 2011 – A retrospective study

BackgroundIn September 2011, the German Standing Committee on Vaccinations (STIKO) changed their recommendation regarding the mumps–measles–rubella–varicella vaccination (MMRV). We compared the immunization rates against MMRV in Germany before and after the STIKO intervention.MethodsWe recorded the immunization status of children born between 09/2008 and 08/2012 in 35 selected doctor’s surgeries in Germany.ResultsAfter the STIKO intervention, the ratio of the combined MMRV vaccine as the first dose immunization was reduced to approximately 25% of the initial value. A slight increase in the number of children not sufficiently vaccinated against varicella (1.2%) was observed, but the immunization rates against measles, mumps, rubella and varicella did not significantly decrease.ConclusionsThe STIKO intervention led to a significant change in physicians’ vaccination procedures. The separate administration MMR + V vaccination may be a helpful option to improve the immunization rates in general.     

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.     

Prevalence and decay of maternal pneumococcal and meningococcal antibodies: A meta-analysis of type-specific decay rates

BackgroundAt the time of an infant’s initial vaccination at age ∼2 to 3 months, some infants already have maternal antibodies against vaccine antigens and these can suppress the immune response to vaccination. Modelling the effects of maternal antibody and the timing of infant doses on the antibody response to vaccination, requires estimates of the rate of maternal antibody decay. Decay rates are not well characterised in the medical literature. We investigated variation in the prevalence of maternal anti-capsular pneumococcal and meningococcal antibodies in infants in 14 countries, and estimated type-specific half-lives.MethodsIndividual participant serological data were obtained from clinical trials. Half-lives were estimated from antibody concentrations in infants who did not receive meningococcal or pneumococcal vaccines.ResultsThe seroprevalence of maternal pneumococcal antibodies was highest for serotypes 14, and 19F (92% and 80% respectively) and lowest for serotypes 4 and 1 (30% and 34% respectively). Half-life estimates ranged from 38.7 days (95% CI 36.6–41.0) for serotype 6B, to 48.3 days (95% CI 46.7–50.2) for serotype 5. The overall half-life was 42.6 days (95% CI 41.5–43.7). Seroprevalence was highest in Mali, Nigeria, India, and the Philippines, (all >65%) and lowest in the Czech Republic and Finland (both <45%).In studies of meningococcal vaccines, seroprevalence was 13% for group C (half-life 39.8 days, 95% CI 33.4–49.4) and 43% for group A (half-life 43.1 days 95% CI 39.8–47.2).ConclusionSubstantial proportions of infants in many countries have antibodies to vaccine serotypes of pneumococcus, however fewer infants have maternally acquired antibodies to groups A and C meningococcus.Passively-acquired antibodies to capsular polysaccharides decay with a half-life of approximately 6 weeks. These estimates are useful for modelling the impact of proposed vaccination programmes, and consideration of schedules with a delayed start.     

Measles seroprevalence in Chiradzulu district,Malawi: Implications for evaluating vaccine coverage

IntroductionSelf-reported measles vaccination coverage is frequently used to inform vaccination strategies in resource-poor settings. However, little is known to what extent this is a reliable indicator of underlying seroprotection, information that could provide guidance ensuring the success of measles control and elimination strategies.MethodsAs part of a study exploring HIV infection and measles susceptibility, we conveniently sampled consenting HIV-uninfected patients presenting at the HIV voluntary counselling and testing centre, and HIV-infected patients presenting for regular care, in Chiradzulu district hospital, Malawi, between January and September 2012.ResultsA total of 2106 participants were recruited between January and September 2012, three quarters of whom were HIV positive. Vaccination cards were available for just 7 participants (0.36%). 91.9% of participants were measles seropositive.Older age (OR = 1.11 per year increase in age; 95%CI: 1.09–1.14) and being female (OR = 1.90; 95%CI: 1.26–2.87) were both associated with significantly increased odds for seroprotection. Prior vaccination history was associated with lower odds (Odds Ratio (OR) = 0.44; 95% confidence interval (CI): 0.22–0.85) for confirmed seropositivity. Previous measles infection was not significantly associated with seroprotection (OR = 1.31; 95%CI: 0.49–3.51).Protection by history and serological status were concordant for 64.3% of participants <35 years old. However, analysis by age group reveals important differences in concordance between the ages, with a greater degree of discordance among younger ages.Vaccination and/or infection history as a predictor of seropositivity was 75.8% sensitive, but just 10.3% specific.ConclusionReported vaccination and previous infection were poor predictors of seropositivity, suggesting these may be unreliable indicators of seroprotection status. Such serosurveys may be indicated in similar settings in which overestimation of the proportion of seroprotected individuals could have important ramifications if used to guide vaccination strategies.     

Pre-vaccination evolution of antibodies among infants 0, 3 and 6 months of age: A longitudinal analysis of measles,enterovirus 71 and coxsackievirus 16

BackgroundDue to waning levels of maternal antibodies (measles; enterovirus 71, EV71; and coxsackievirus A16, CoxA16), some infants may lose protection against infection prior to vaccination. Using a longitudinal design, we examine how maternal antibody levels evolve over time in infants prior to vaccination.MethodsIn 2013–2014, we collected sera at ages 0, 3 and 6 months from infants. We assayed for levels of measles IgG antibody (717, 233 and 75 sample sera tested at months 0, 3 and 6, respectively), and neutralizing antibodies for EV71 and CoxA16 (225, 217, and 72). Demographic and health information were collected, and a linear mixed model (LMM) was used to describe antibody levels over time.ResultsPre-vaccination monotonic antibody decreases were observed for measles (1410, 195 and 22 mIU/ml, p < 0.001), EV71 (1:19.9, 6.3 and 4.5, p < 0.001) and CoxA16 (1:16.3, 5.9, and 4.5, p < 0.001). At 6 months of age, only 2.7% (95%CI, 0.6–8.3), 6.8% (95%CI, 2.7–14.4) and 5.6% (95%CI, 1.9–12.7) of infants were antibody positive for measles, EV71 and CoxA16, respectively. LMM findings indicated that infants with higher antibody titers at birth experienced a greater loss of antibody level. An infection rate of 1.3% (95%CI, 0.1–6.1) was reported for both EV71 and CoxA16.ConclusionsFurther modifications of vaccination strategies for measles, earlier vaccination for EV71 infection, and deployment of a CoxA16 vaccine need to be considered to limit infection among the very young.     

Monitoring the process of measles elimination by serosurveillance data: The Apulian 2012 study

In 2003 Italy adopted the National Plan for Measles and Congenital Rubella Elimination, but some outbreaks of measles are still occurring, as the target coverage rate (≥95%) for new-borns has currently not been achieved.In order to support the monitoring of the measles elimination programme, the authors carried out a survey about the seroprevalence of measles among Apulia young adults.The study was carried out from May 2011 to June 2012 among blood donors of the Department of Transfusion Medicine of Policlinico General Hospital in Bari. Subjects were enrolled by a convenience sampling. For each enrolled patient we collected a 5 mL serum sample. Collected sera were tested by chemiluminescence (CLIA) for anti-Measles IgG.We enrolled 1764 subjects; 1362 (77.2%) were male with a mean age of 38.4 ± 11.7 years. Anti-Measles IgG titre was >16.5 UA/mL in 95.1% (95% CI = 94.1–96.1) of enrolled subjects with a Geometric Mean Titre (GMT) of 2.3 ± 0.4, which did not differ dividing the enrolled subjects into age groups.As our data showed, the universal routine vaccination changed the epidemiological pattern among adults, in particular young adults (18–24 years), who showed lowest seropositivity rates; in these groups of population there is a risk of the onset of outbreaks due to the presence of susceptible population. This is a paradox linked to the vaccination strategy: when coverage rates keep sub-optimal, measles is more likely to affect young adults and a higher percentage of complications is expected. According to our data, health authorities have to plan a mop-up strategy to actively offer measles vaccination to susceptible young adults.     

Comparing the rubella seronegativity in pregnant women who received one dose of rubella vaccine at different ages in Taiwan

IntroductionVaccination is the best strategy to prevent rubella and congenital rubella. The aim of our study was to assess the immunity to rubella and determine rubella virus antibody titers in pregnant women who were offered a single dose of rubella vaccine at different ages of their lives.MethodsA total 15,067 rubella IgG antibody test results for Taiwanese pregnant women who received routine prenatal checkup at Fooyin University Hospital from 1999 to 2014 were analyzed in this study. The women were divided into five birth cohorts in order to compare their rubella seronegativities and antibody titers according to the different period of rubella vaccination policy in Taiwan.ResultsThe total rubella seronegativity rate was 11.2% (95% CI: 10.7–11.7%) and the mean rubella antibody titers was 51.0 IU/mL (SD = 54.7 IU/mL). The junior school cohort has the lowest rubella seronegativity of 7.6% (95% CI: 6.9–8.2%). The seronegativities were significantly high in the preschool cohort and in the 15-month-old cohort, 14.9% (95% CI: 13.2–16.6%) and 14.8% (95% CI: 11.5–18.1%), respectively. The OR values were 2.1 (95% CI: 1.8–2.5, p < 0.001) in the preschool cohort and 2.2 (95% CI: 1.6–2.8, p < 0.001) in the 15-month-old cohort, respectively, against the junior school cohort. Women in the 15-month-old cohort have lowest average rubella IgG titer, 25.4 IU/mL.ConclusionThe total rubella seronegativity rate was 11.2% in all native pregnant women. Women who received one dose rubella vaccine at preschool and 15-month-old have highest seronegativities. The 15-month-old cohort has the lowest average rubella IgG titer. We recommend a revised catch-up immunization policy to women who received one dose rubella vaccine at a younger age.     

A hospital-associated measles outbreak among individuals not targeted for vaccination in eastern China, 2014

BackgroundAn outbreak of measles occurred in early 2014 among individuals not targeted for vaccination—adults, and infants too young to vaccinate, in Xiangshan County, Zhejiang Province, in eastern China.ObjectiveWe conducted an investigation to identify risk factors responsible for this outbreak and to provide evidence-based recommendations for measles elimination strategies in China.MethodsMeasles was diagnosed using national standard case definitions. In a case-control study, 20 randomly selected measles patients were matched with controls selected from the same village or community as each case in a 1:2 case-to-control ratio. Controls were matched on age, within 5 years, and gender. We compared exposure histories during the 7–21 days before rash onset of the case and the same time period for the matched controls. We also conducted a measles antibody seroprevalence survey of a convenient sample of residual serum obtained from healthy patients during routine care in a hospital.ResultsThe outbreak consisted of 45 measles cases, with an attack rate of 8.9/100,000 total population. Among cases, 91.1% (41/45) were adults (ranged 23–51 years) who had unknown vaccination histories; the other cases were infants younger than 8 months of age. The case-control study showed major risk factors to be a visit to Hospital X (OR_MH = 7.3, 95% CI: 1.8–30.7) and treatment in an IV room in Hospital X (OR_MH = 11.0, 95% CI: 1.3–96.1). The seroprevalence survey showed that 88.8% of adults had measles IgG antibodies, and that 100% of children 2–19 years of age were seropositive.ConclusionsThe outbreak was primarily among age groups not targeted for vaccination—primarily adults, but with some children too young to vaccinate. Visiting a hospital was the major risk factor for measles transmission. We conclude that in addition to maintaining high 2-dose coverage with measles vaccine, working with hospital infection control programs to implement evidence-based strategies to prevent or limit hospital transmission is an important action for eliminating measles in eastern China.     

Persistence of measles antibodies,following changes in the recommended age for the second dose of MMR-vaccine in Portugal

In populations vaccinated with two doses of combined measles–mumps–rubella vaccine (MMR), the serum levels of antibodies against measles depend on the vaccination schedule, time elapsed from the last dose and the area-specific epidemiological situation. Variables measuring “schedule” are age at first and second doses of MMR and intervals derived from that. Changes in vaccination schedules have been made in Portugal. The specific objectives of this study were to measure the association between those potential determinants and the concentration of measles-specific IgG antibodies, after the second dose of MMR. Convenience samples of three Portuguese birth cohorts were selected for this study (41, 66 and 60 born, respectively, in 2001–2003, 1990–1993 and 1994–1995). Geometric mean concentrations (GMC) for measles IgG were, respectively, 934, 251 and 144 mIU/ml; p < 0.001). Anti-measles-IgG serum concentration decreased with time since last vaccination (waning immunity) and was not influenced by any other component of vaccination schedule, namely age at vaccination with the second dose of MMR. Waning levels of measles antibodies have been observed elsewhere but not as fast as it was observed in Portuguese birth cohorts in this study. Changes in the vaccination schedules might have to be considered in the future.     

Seroprevalence of antibodies against serogroup C meningococci in the region of Valencia,Spain: Impact of meningococcal C conjugate vaccination

Background and aimsMeningococcal C conjugate (MCC) vaccination programs provide direct and indirect protection against meningococcal disease. However, a decrease in the antibodies could affect herd immunity. We conducted a seroprevalence study to assess the immunity in subjects 8–12 years after different MCCV vaccination programs were launched and evaluated the impact of vaccination on seroprotection.MethodsSeroepidemiological study conducted from October 2010 to April 2012 in the region of Valencia, Spain. Sample size was not proportional to the population but to the expected seroprotection by age group. Sera from subjects that were ≥ 3 years old were tested using a standardized complement-mediated serum bactericidal antibodies (SBA) assay. Age-stratified proportions of subjects with SBA titers ≥ 8 were considered seroprotected and evaluated. A multivariate logistic regression model was performed to evaluate the impact of vaccination on the seroprotection.ResultsSerum samples from 1880 subjects were collected. In total, 523 (27.8%) of the 1880 subjects and 446 (31.2%) of the 1430 subjects < 30 years (targeted to any vaccination campaign) showed protective SBA titers. The highest percentage of seroprotected subjects (67.8%, 95%CI 56.9–77.4) was observed in those that were vaccinated in a catch-up campaign at 10–13 years of age (20–21 years old at the time of blood sampling). Those scheduled for immunization in infancy at 2, 4 and 6 months of age (7–8 years at blood sample) represented the lowest (7.1%, 95% CI 3.3–13.1) number of seroprotected subjects. Having received one vaccine dose after 12 months of age was associated with increased seroprotection. The present study revealed a positive correlation between the increasing age at vaccination and longer duration of seroprotection.ConclusionOnly one in three subjects who were vaccinated with MCC vaccine was seroprotected after 8–12 years. These findings emphasize that seroprevalence studies are essential to identify susceptible cohorts and to inform vaccine policy.     

Age-stratified seroprevalence of measles, mumps and rubella (MMR) virus infections in Switzerland after the introduction of MMR mass vaccination

We have performed age-stratified seroprevalence studies for MMR to evaluate these vaccinations. Serum samples submitted for diagnostic testing were randomly selected for unlinked anonymous panels. IgG antibodies were tested by ELISA and indirect immunofluorescence. In the vaccination cohort (age 1.5 to 6.5 years), seroprevalence attained 80%. For measles and mumps it continued to increase to 95%, while for rubella it declined transiently to 60% between 7 and 12 years of age. We observed no differences according to gender in any age group in 1991--1992. (Semi)quantitative values of the IgG antibodies against all three viruses increased during adolescence, suggesting wild virus circulation. In 1992, MMR vaccination has reached < 80% of the children during their second year of age. Due to previous monovalent measles and mumps vaccinations in pre-school children and due to endemic and epidemic activity, particularly of mumps virus, a trough of the seroprevalence in adolescents was evident only for rubella. MMR vaccination campaigns performed at school since 1987 have increased seroprevalence in this population segment and have probably over-compensated for the expected shift to the right of the seroprevalence curves. A more compulsive implementation of the recommended childhood vaccination schedule and continued efforts at catchup vaccinations during school age especially for rubella are necessary to avoid the accumulation of susceptible young adults during the forthcoming decades.     

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.     

Birth outcomes for Australian mother-infant pairs who received an influenza vaccine during pregnancy, 2012–2014: The FluMum study

IntroductionIn Australia, influenza vaccination is recommended for all women who will be pregnant during the influenza season. Vaccine safety and effectiveness are key concerns and influencers of uptake for both vaccine providers and families. We assessed the safety of receiving an influenza vaccination during any trimester of pregnancy with respect to preterm births and infant birthweight.MethodsWe conducted a nested retrospective cohort study of ‘FluMum’ participants (2012–2014). Our primary exposure of interest was influenza vaccination during pregnancy. The primary outcomes of interest were infant birthweight and weeks’ gestation at birth for live singleton infants. Analyses included comparisons of these birth outcomes by vaccination status and trimester of pregnancy an influenza vaccine was given. We calculated means, proportions, and relative risks and performed multivariable logistic regression for potential confounding factors.ResultsIn the 7126 mother-infant pairs enrolled in this study, mean maternal age at infant birth was 31.7 years. Influenza vaccine uptake in pregnancy was 34%. Most mothers with a known date of vaccination received a vaccine in the second trimester (51%). Those mothers with a co-morbidity or risk factor were 13% more likely to have influenza vaccine during pregnancy compared to other mothers (RR 1.13, 95% CI 1.04–1.24, p = 0.007). Mean weeks’ gestation at birth was 38.7 for the vaccinated and 38.8 for the unvaccinated group (p = 0.051). Infants in the vaccinated group weighed 15 g less in birthweight compared to the unvaccinated infants (95% CI −12.8 to 42.2, p = 0.29).ConclusionResults arising from this large Australian cohort study are reassuring with respect to two critical safety outcomes; preterm births and low infant birthweights. Studies examining a broader range of birth outcomes following influenza vaccination during pregnancy are required, particularly now that maternal vaccination in pregnancy has expanded to include pertussis as well as influenza.     

Immunity against infectious diseases: predictive value of self-reported history of vaccination and disease.

OBJECTIVE: To determine whether self-reported history of disease and/or vaccination is predictive of immunity against hepatitis B, varicella, rubella, mumps, and measles. DESIGN: The seroprevalence of viral antibodies and the predictive value of a self-report questionnaire were determined for 616 paramedical students who matriculated into Padua Medical School (Padua, Italy) during 2003-2005. RESULTS: The majority of subjects (86.9%) remembered being vaccinated against hepatitis B but had no recollection of disease. Among vaccinees, 1.5% showed markers of previous infection, 6.7% tested negative for anti-hepatitis B virus surface antigen (anti-HBsAg) antibodies, and 91.8% tested positive for anti-HBsAg. Self-reported vaccination history had a positive predictive value of 93.2% for test results positive for immunity against hepatitis B. Immunity against varicella (93.7% of subjects) and rubella (95.5%) was high, compared with immunity against mumps (79.9%) and measles (83.1%). In addition, results of tests for detection of immunity against mumps and measles were equivocal for more than 7% of subjects, probably because their vaccination regimen was not completed. Self-reported histories of varicella disease and rubella disease and vaccination had high positive predictive values (greater than 98% each) for testing positive for antiviral antibodies, compared with self-reported histories of mumps disease and vaccination and measles disease and vaccination; however, high positive predictive values were observed for self-reported histories of mumps only (92.0%) and measles only (94.7%). CONCLUSIONS: The self-report questionnaire used in this study did not accurately predict immunity against 5 transmittable but vaccine-preventable diseases. A complete serological evaluation of healthcare workers, followed by vaccination of those with negative or equivocal results of serological tests, is an appropriate measure to decrease the risk of infection in this population.