Measles IgG Antibody Research Articles

Optimization and Stability Testing of Four Commercially Available Dried Blood Spot Devices for Estimating Measles and Rubella IgG Antibodies.

ABSTRACTBlood collection using dried blood spots (DBS) provides an easier alternative to venipuncture for sample collection, transport, and storage but requires additional processing that can cause variability in results. Whole-blood samples spotted on four DBS devices and respective paired serum samples were tested for antimeasles and antirubella IgG antibody concentrations by enzyme immunoassay. Elution protocols for DBS devices were optimized for comparability relative to serum samples using 12 adult volunteers. Stability of DBS collected on HemaSpot HF was assessed under various temperature conditions (+4, 22 to 25, and 45°C) at six time points (0, 7, 15, 30, 60, and 90 days) in a controlled laboratory setting using six adult volunteers. Devices were shipped and stored for 30 days at four settings with variable temperature and humidity conditions to assess the impact on antibody concentrations. Three DBS devices demonstrated comparable antibody concentrations with paired sera following optimization. Antibodies recovered from DBS were stable for at least 90 days at 4°C and for 30 days at ambient temperature (22 to 25°C) using the HemaSpot HF device. A drastic decline in antibody concentrations was observed at 45°C, resulting in quantitative and qualitative discrepancies by day 7. HemaSpot HF devices shipped to field sites and stored at ambient temperature and humidity resulted in quantitative, but not qualitative, variability. Measurement of antimeasles and antirubella IgG antibodies with DBS devices is an accurate alternative to testing serum, provided elution protocols are optimized. Stability of HemaSpot HF devices at ambient temperature enables broader use in surveys when serum processing and cold storage are not feasible.IMPORTANCE Dried blood spot (DBS) collection offers various advantages over conventional methods of blood collection, especially when collecting and transporting samples for a serosurvey. Yet use of DBS requires additional processing steps in the laboratory that can add to variability in results. We optimized a protocol to elute IgG antibodies against measles and rubella viruses in four DBS devices, demonstrating high concordance with paired venous sera for most devices. Extensive stability studies with various temperature and storage conditions in the laboratory and in the field were conducted using HemaSpot HF DBS devices prior to its use in one of the largest community-based measles and rubella serological surveys in the world.

Immunogenicity and safety of concomitant inoculation of Measles and rubella combined live vaccine and Japanese encephalitis attenuated live vaccine

Objective: To evaluate the immunogenicity and safety of concomitant inoculation of Measles and Rubella Combined Live-attenuated Japanese encephalitis vaccine. Methods: Healthy children aged 8 months in selected cities in Zhejiang Province were randomly assigned to the MR and JVE-L combined vaccination group (the experimental group), and the MR single vaccination group (the control group) was taken before the exemption and 6 weeks after the exemption. Peripheral venous blood 1 ml was used as serum antibody test for measles and rubella, and the levels of measles and rubella antibodies before and after vaccination were evaluated. The safety of combined vaccination was evaluated. Measles and rubella IgG antibodies were detected by enzyme-linked immunosorbent assay (ELISA). Data were double-entry with Epidata and statistical analysis was performed using Epi Info epidemiological statistical analysis software. Results: The results showed that no severe adverse event occurred in two groups, clinical reactions in each inoculation group were mild.The seroconversion rate of measles antibody and rubella antibody were 96.43% and 88.49% in the experimental group after vaccination, the geometrical mean concentrations(GMC) of measles antibody was 1 526.45 mIU/ml and the GMC of rubella antibody was 47.70 mIU/ml after concomitant inoculation; the seroconversion rate of measles antibody and rubella antibody were 97.62% and 86.11% in the control group, the GMC of Measles antibody was 1 392.28 mIU/ml and the GMC of Rubella antibody was 45.72 mIU/ml after MV inoculation. No difference were detected in two groups of seroconversion rate of measles antibody and rubella antibody and GMC after vaccination. Conclusion: The immunogenicity and safety is equivalent when MR and JVE-L were simultaneous inoculation.

Preclinical toxicological evaluation of measles virus vaccine strain in non-human primates: A two-month intravenous study

Introduction: Based on its ability to kill tumor cells, the vaccine strain of the measles virus is used for oncolytic virotherapy. However, the dose required for cancer therapy is much higher than that used for vaccination. Therefore, this study was conducted to evaluate the preclinical toxicology of the vaccine strain of measles virus in monkeys.
 Methods: 16 healthy Macaca mulata monkeys were randomly divided into four groups, of which one was a control. A preclinical safety evaluation of the vaccine strain of the measles virus was performed, and the three experimental groups were intravenously injected with the strain at doses of 105 TCID50, 106 TCID50 and 107 TCID50 respectively.
 Results: There were no significant abnormalities in the physical, clinical, haematological, and biochemical parameters following the intravenous injection with measles vaccine at doses of 105 TCID50, 106 TCID50 and 107 TCID50. The vaccine strain of measles virus remained in the plasma until the 30th day and disappeared on the 60th, and it did not persist in the tissues on days 30 and 60 post injection. Measles IgG antibody was negative on days 0, 1, 3, and 8 and was positive on days 15, 30, and 60 post administration of the measles virus. The histopathology of target organs was not affected in all groups on days 30 and 60 post injection.
 Conclusions: The systematic preclinical safety data of the present study confirms the safety of two months of concentrated measles vaccine administration in the Macaca mulata monkey for clinical trials.

Risk of Absence of Measles Antibody in Healthcare Personnel and Efficacy of Booster Vaccination

We aimed to identify the presence of the measles IgG antibody (mIgG-Ab) in healthcare personnel and finding out who needs the measles vaccination. The history of measles vaccination was obtained from the national vaccine registry. A baseline mIgG-Ab test was performed, and the measles vaccine was administered to participants who tested negative or equivocal for mIgG-Abs. During the study, 2885 (87.3%) of the 3303 employees were tested for measles serostatus. The baseline seropositivity rate for mIgG-Abs was 91.9%. Among the 234 seronegative cases, 82.9% were born after 1985. The seroprevalence rate was lower in those who received the measles–mumps–rubella (MMR) vaccine >10 years before the testing time, especially if they were born after 1985 and if there was only one previous record of vaccination. Among the 234 seronegative cases, MMR vaccination was administered in 174 cases, of which serostatus was evaluated in 146 cases. After the first dose, positive seroconversion was achieved in 126 participants (86.3%). After a second dose, 15 achieved (75.0%) positive seroconversion. In healthcare personnel born after the period when measles incidence significantly decreased, it may be necessary to reassess their immune status for measles if more than 10 years have elapsed since the last vaccination.

Low Seroprevalence of Measles-Specific IgG in Children of Three Ethnic Groups from Mexico: Influence of Age, Sex, Malnutrition and Family Size.

Background: The reemergence of measles represents a public health problem. The aim of the study was to determine the seroprevalence of IgG antibodies against measles in children of three ethnic groups in southern Mexico and the nutritional status and demographic risk factors associated. Methods: A cross-sectional study in 416 school-age children, 207 belonging to the Tlapaneco ethnic group, 101 to the Mixteco group and 108 were considered Mestizo. Sociodemographic data were collected, an anthropometric evaluation of the children was performed and a fasting blood sample was obtained from each child for the measurement of measles IgG antibodies by Enzyme-Linked Immunosorbent Assay (ELISA). Results: From the total sample, 59% of the children were seropositive for IgG antibodies against measles; in contrast, 41% lacked IgG antibodies. Measles antibody seropositivity was higher in girls (64%). 90.5% of 6-year-old children had higher antibodies seroprevalence, compared to the children between 10 and 13 years old (45.5%). In the three ethnic groups, age was negatively correlated with the index standard ratio (ISR) of measles antibody levels and the families with ≥8 members showed less seropositivity. According to the antibodies levels, most of the positive cases remained around 1 Standard Deviation (SD) of the ISR values and no underweight children had antibody levels above 2 SD. Conclusions: The Anti-Measles serological coverage is low in children of three ethnic groups from Southern Mexico and the age, sex, malnutrition and family size are associated factors. Therefore, it is important to strengthen immunization campaigns, principally in vulnerable groups.

Contribution of measles virus IgG antibody avidity assay to the identification of measles cases

Objective: To evaluate the value of measles IgG antibody avidity assay in identifying the measles cases. Methods: Data from the Measles Surveillance Information System was used to collect laboratory confirmed or discarded cases in 2013-2015, and then tracing back the blood specimens from all measles network laboratories in Tianjin. Measles antibody avidity assay was used to detect and to redefine cases from the discarded ones. Results: A total of 326 measles cases including 267 laboratory-confirmed and 59 discarded cases were enrolled into this study, with 92.33% (301/326) of them aged ≥20 years. Result from the measles IgG antibody avidity assay showed that the ratio of high-avidity was 91.23%(52/57) of the discarded cases, which was significantly higher than 66.95% (158/236) of the laboratory confirmed cases (χ2=13.33, P<0.001). According to the case criterion, 15.25% (9/59) of the discarded cases were redefined as measles cases. Eight out of the nine cases were high-avidity with measles containing vaccine (MCV) vaccination history that named as SVF cases. One in nine cases with low-avidity was with typical clinical symptomatic measles but with no vaccination history of MCV. Conclusion: Measles IgG antibody avidity assay could provide reference serological evidence to reduce the error from those discarded cases caused by false negative results on IgM antibody, when diagnosing the measles cases.

Three-year prevalence of measles antibody seropositivity at a tertiary care hospital in Turkey

Objective: Measles virus is an unsegmented, single-stranded and negative-polarized RNA virus belonging to Morbillivirus genus in Paramyxoviridae family in the order of Mononegavirales. This study aimed to evaluate measles antibody seropositivity proportions in different age groups from different geographical regions within three years. Material and methods: This retrospective study, IgM and IgG antibodies specific to measles were detected in serum samples with enzyme immunoassay method. Measles IgG antibody seroprevalence was calculated by correlating all data with demographic variables. Results: Median age of patients included in the study was 27 years and while 352 (44.4%) were male. Seropositivity rate of measles IgG antibody was 87.1%. Seropositivity in the age group of 0-18 was 77.7% (p = 0.002). IgG seropositivity rates were 82.8%, 88.8% and 90.7% between 2017 and 2019 respectively (p = 0.05). Seropositivity rate of IgM antibody in all cases was 11.1% and the highest rate was detected in the age group of 0-18 (13.5%) (p = 0.09). IgM antibody seropositivity rate was determined most in the winter months (23.8%) (p < 0.001). While measles IgM positivities were 10.6% and 21.1% in Turkish and foreign patients respectively IgG positivities were 86.9% and 92.3% (p = 0.32, p = 1.00 respectively). Measles IgG seropositivity was the highest in patients living in Aegean region (96.8%). Conclusions: In conclusion, measles IgG seropositivity was 87.1% in this study. This rate was lower in pediatric age group. Increasing regional seroprevalence studies may help enhancement efforts on vaccination program to reach and sustain high population immunity.

A Cross-sectional Serological Study for Measles among Italian Medical Students in 2020

Background: Measles is an infectious disease and a major health concern worldwide. Among individuals with a higher risk of exposure to measles, there are the Health Care Workers (HCWs), who may transmit the virus to other people. According to the Italian National Plan for Immunization and Prevention, all HCWs should have presumptive evidence of immunity to measles (documented two doses of MMR vaccination) or serological evidence of protective antibodies. Aim: The study aims to evaluate the immunological status, the vaccine coverage, and the protective IgG antibody titre for measles in medical students of the teaching hospital PoliclinicoTor Vergata (PTV). Methods: IgG measles antibodies titre was evaluated in a sample of 461 medical students undergoing annual health surveillance visits from January 1st to May 31th, 2020. Results: 73.7% of medical students showed protective measles IgG antibody levels. The immunization rate was higher among subjects aged less than 25 years with respect to students aged over 25 years (77.4% vs. 66.4%; P &lt;0,001). Furthermore, average antibody titre showed a statistically significant association with the age group (124,2 AU/ml for the age group 18-25 and 133,2 AU/ml among subjects aged 25 or more; P&lt;0.001). Conclusion: Our study shows a non-protective measles IgG antibody titre, especially among the older students. Therefore, it is essential to evaluate the serological levels, to vaccinate those subjects whose antibody level is not adequate, and promote the vaccination even in the general population.

How well are patients with inflammatory rheumatic diseases protected against measles?

HintergrundPatienten mit entzündlich rheumatischen Erkrankungen haben aufgrund ihrer Autoimmunerkrankung, aber auch bedingt durch die immunsuppressive Medikation ein erhöhtes Infektrisiko. Obwohl Impfungen in der Primärprophylaxe von Infektionen bekanntermaßen effektiv sind, ist die Impfrate in Deutschland generell zu niedrig. Wegen des zuletzt zunehmenden, teils epidemieartigen Auftretens von Masern ist die Lebendimpfung gegen Masern in Deutschland seit Kurzem gesetzlich vorgeschrieben.FragestellungWie viele Patienten mit entzündlich rheumatischen Erkrankungen sind aktuell ausreichend gegen Masern geschützt?MethodePatienten mit entzündlich rheumatischen Erkrankungen des Rheumazentrums Ruhrgebiet wurden zwischen Dezember 2017 und Oktober 2018 prospektiv und konsekutiv eingeschlossen. Dabei wurden Daten zu Erkrankung und Therapie auf Ebene von Substanzklassen sowie die Impf- und Infektanamnese erhoben. Alle Angaben zu Impfungen wurden im Impfpass kontrolliert. Antikörpertiter gegen Masern wurden mit ELISA bestimmt. Als Schwellenwert für einen ausreichenden Schutz gegen Masern wurden 150 mIU/ml festgelegt.ErgebnisVon 975 Patienten konnten 540 (55,4 %) einen Impfausweis vorlegen. Bei 201 Patienten mit Ausweis (37,2 %) lagen dokumentierte Impfungen seit Geburt vor. Insgesamt hatten 45 von 267 nach 1970 geborene Patienten (16,9 %) einen suffizienten Impfschutz gegen Masern. Die anamnestischen Angaben zu einer Masernerkrankung in der Kindheit differenzierten nicht zwischen Patienten mit und ohne protektiven Masern-IgG-Antikörpern. Protektive Masern-IgG-Antikörper wurden bei 901 Patienten von 928 Patienten mit Messung der Masern-IgG-Antikörperspiegel (97,1 %) nachgewiesen. Die unterschiedlichen Wirkprinzipien der aktuellen immunsuppressiven Therapie hatten darauf keinen Einfluss.DiskussionDiese Daten zeigen, dass mindestens 2,9 % der Patienten keinen ausreichenden Schutz gegen Masern haben. Interessanterweise hatte die Mehrheit der nach 1970 geborenen Patienten protektive Antikörper trotz fehlenden Impfschutzes gegen Masern. Die Anstrengungen sowohl im primär- als auch im fachärztlichen Bereich sollten dringend verstärkt werden, um eine adäquate Infektionsprophylaxe bei besonders gefährdeten Patienten gewährleisten zu können.

Surprisingly Low Levels of Measles Immunity in Persons With HIV: A Seroprevalence Survey in a United States HIV Clinic.

BackgroundMeasles outbreaks have become increasingly common due to deteriorating vaccination rates, fluctuating herd immunity, and varying antibody decline. Limited knowledge exists regarding prevalence and risk factors associated with measles seronegativity among persons with HIV (PWH).MethodsThis was a cross-sectional study conducted at an academic HIV clinic in Omaha, Nebraska. Participants were screened for the presence of measles IgG antibody. Demographic and clinical information was obtained through electronic medical record review. Simple and multivariable logistic regressions were performed to identify risk factors for measles seronegativity.ResultsThree hundred fifty-one participants were enrolled, with a measles seroprevalence rate of 70.3%. The mean age (range) was 48 (20–74) years, 77% were male, and 53% were Caucasian. The mean CD4 nadir (range) was 334 (1–1675) cells/mm3. At the time of testing, 86% and 87% of the seronegative and seropositive participants had an HIV RNA <50 copies/mL, respectively. Younger age was significantly associated with measles seronegativity (P = .003), as was birth year after 1957 (P = .021). Prior history of measles infection was associated with seropositivity (P = .011). All other risk factors evaluated, including written documentation of adequate vaccination, were not associated with seronegativity.ConclusionsOur study demonstrates a measles seroprevalence rate that is remarkably lower than previously reported in PWH (92%), and, more importantly, is considerably lower than the rate needed to maintain herd immunity (95%). With higher than expected seronegativity and absence of notable risk factors aside from age, our findings support expanded measles immunity screening for PWH who are at risk of measles exposure.

Measles humoral immunity in health-care workers

Healthcare-workers are at risk of contact with measles patients and disease transmission. Measles-infected employees of healthcare facilities may contribute to the nosocomial measles spread and serve as a source of infection for most susceptible cohorts such as pregnant women, neonates, and immunocompromised patients. In order to study the humoral immunity against measles in healthcare workers and reveal factors associated with seronegative status, we performed a cross-sectional study by enrolling 847 healthcare workers of the Arkhangelsk Regional Clinical Hospital. Anti-measles virus serum immunoglobulin G antibodies were quantified by using VectorMeasles-IgG ELISA kit (Vector-Best, Russia). According to the manufacturer's recommendations specific IgG anti-measles titer cut-off value higher than 0.18 IU/ml, equal to 0.12—0.17 IU/ml, or lower than 0.12 IU/ml was considered as positive (protective), equivocal, or negative, respectively. Assessing an impact of employee's gender, age, affiliation (department), current position was carried out by using binary logistic regression analysis while analyzing seronegative status of healthcare workers. Study participants dominated by females (92.1%). The median age was 48 (39; 57) years. The employees of somatic departments prevailed (26.7%). It was found that 93.7% of medical workers had concentration of anti-measles antibodies exceeding magnitude of protective titer (above 0.18 IU/ml), 4.4% and 1.9% were measles seronegative and equivocal, respectively. The level of antibodies against measles was associated with age of healthcare workers, but not with gender. All employees older than 60 years were measles seropositive, whereas those younger than 35 or within range 35 to 60 years of age had protective antibody titer in 77% and 95.5% of cases, respectively. The proportion of subjects with seronegative results did not depend on employee's position (doctor, nurse, cleaning worker), but varied a lot between different hospital departments. According to the data of logistic regression, the odds to have a seronegative test result among employees from somatic and remaining departments were 4.4-fold higher. Importantly, the rate of seronegative results was by 10-fold lower in employees born between 1968 and 1984 than those found in subjects born after 1985. On the other hand, subjects older than 60 years of age were seronegative at 50-fold lower rate than those who were under 35. The median concentration of measles immunoglobulin G among vaccinated healthcare workers vs. subjects recovered after natural infection was significantly lower reaching 0.56 IU/ml and 4.2 IU/ml (p 0.001), respectively. Five-year monitoring showed that titer of measles IgG antibodies decreased by 1.2-1.9-fold (average — 1.5). Thus, a cohort of healthcare workers from multidisciplinary healthcare facility demonstrated that the proportion measles-susceptible subjects was 6.3%. Importantly, age of examined subjects mainly affected seronegative status. Taking into consideration age-related lowered serum antibody level in vaccinated healthcare workers, seroprevalence studies and subsequent revaccination of seronegative people should be performed at least once every 5 years to prevent measles spread in healthcare facilities.

Evaluating the population measles susceptibility in Tianjin, China

BackgroundMeasles is a highly infectious illness requiring herd immunity of 95% to interrupt transmission. China has not reached elimination goals despite high vaccination coverage. We estimated the population susceptibility against measles in Tianjin, China and to tailor awareness raising activities in the measles elimination plan. MethodsAge-specific measles seroprevalence was evaluated by Enzyme-Linked Immunosorbent Assay (ELISA) on 12,164 individual aged 0–44 years in 2009–2018. Measles IgG avidity testing was performed to confirm the relationship of the waning immunity after vaccination and secondary vaccination failures (SVF) on 324 confirmed measles cases in 2013–2018. Results11,108 samples (91.32%) tested positive for measles IgG, 239 (1.96%) tested as equivocal and 817 (6.72%) were negative. The age distribution of measles cases in Tianjin followed a U-shaped curve and was highest for those at <8 months and again at 20–39 years which correlated closely with the age distribution of measles susceptibility based on measles IgG antibody status (r = 0.72, P < 0.001). The seropositivity rate and antibody geometric mean concentration (GMC) for the 2018 study population were significantly lower (χ2 = 7.45, P = 0.006 and t = 12.01, P < 0.001) compared to 2009. The multivariate stepwise logistic regression analysis showed that age and region were the risk factors for both measles seropositivity rate and GMC after vaccination. The proportion of high avidity cases increased with age, being significantly higher in 75.31% of cases in patients aged 30–34 years (χ2 = 18.04, P = 0.003). ConclusionsHigh immunization coverage in children alone will not be adequate to realizing sufficient levels of population herd immunity, particularly given that the potential susceptibility window in adult. Implementation of supplemental immunization activity (SIA) targeted to appropriate group aged 30–34 years is recommended.

Level of measles herd immunity assessed in hospital medical workers within a framework of the state measles elimination program

Within a framework of the state measles elimination program, in April, 2018 a level of measles herd immunity was assessed in 1899 Moscow hospital medical workers aged from 19 to 69 years and older. All subjects enrolled in the study were vaccinated against measles or recovered after measles infection. Serum samples were collected from subjects and examined by ELISA for measles IgG antibodies with the Vector-Best IgG-measle test system (Russia). It was found that 278 (14.6%) and 1621 (85.4%) subjects were seronegative ( 0.18 IU/mL) and seropositive ( 0.18 IU/ml), respectively. Age-related group distribution of 1855 serum samples revealed that percentage of seronegative subjects was in: aged 19—23 years was -38.5%; 24-28 and 29-33 years - 22.2%; 34-38 years - 27.5%; 39-43 years - 25.8%; 44-48 years - 16.8%; 49-53 and 54-58 years — 8.6% and 8.3%, respectively; 59-63 years old — 4.9%; 64-68 and over 69 years old — 0%. Moreover, mean level of measles IgG antibodies increased proportionally to age of medical workers from 0.58 IU/ml (19-23 years) to 2.94-2.72 IU/ml (64-68 and over 69 years). The data obtained indicate that a cohort of measles susceptible subjects (from 38.5% to 16.8%), respectively, is identified among young and middle age (from 19 to 48 years) individuals. It is assumed that two-dose measles vaccination in childhood does not contribute to the long-term preservation of protective levels of measles antibodies, thereby justifying a need to administer a three-dose measles vaccine.

Formation of humoral and cellular immunity to measles vaccine in adults

Despite adherence to the policy of mass measles vaccination in the majority of countries, this infection still remains far from being fully eradicated. Measles outbreaks are reported worldwide, when the vast majority of cases are recorded in subjects of 18—35 years of age. Studies on assessing measles IgG antibody level in different regions of Russia reveal increased percentage of measles seronegative subjects among young adults. Current study was aimed at investigating formation of humoral and cellular immunity after measles vaccination in seronegative adults aged 18 to 30 years old. There were enrolled 50 measles seronegative healthy volunteers aged 18 to 30 years old. Level of anti-measles IgM and IgG antibodies was measured by ELISA (Vector-Best, Russia). Subclasses of measles specific IgG antibodies were analyzed by ELISA, by replacing IgG conjugate for IgG1, IgG2, IgG3, IgG4 conjugates, whereas measles specific IgA antibodies were estimated by ELISA with IgA conjugate (Polygnost, Russia) at a concentration of 1 μg/ml. Antibody avidity was assessed by ELISA (Euroimmun, Germany). Cell-mediated measles immunity was estimated by CD107a surface expression on CD8hi T cell subset stimulated by measles virus-derived antigens. A specific cellular response to measles antigens before vaccination was detected in 50% of examined subjects, whereas 40% samples showed no signs of cellular immune response, with 10% of remaining cases described as equivocal. It was found that 6 weeks after vaccination all vaccinated subjects developed measles specific IgG antibodies at protective level reaching 1.33 (0.85—1.82) IU/ml [Me (LQ—UQ)]. Anti-measles IgA antibodies were of 0.655 (0.423—1.208) IU/ml [Me (LQ—UQ)]. However, no measles specific IgM antibodies were detected 6 weeks after vaccination. In addition, primary type of immune response (dominant low-avidity anti-measles antibodies IgG3 subclass) to measles vaccination was observed in 24 out of 50 subjects, whereas 26 subjects developed secondary type of immune response (high-avidity anti-measles antibodies dominated by IgG1 subclass). A measles specific cellular immune response was observed in 47 of the 50 examined subjects, and in 3 volunteers it was equivocal. Further analysis revealed a cohort of subjects who were not vaccinated against measles (18 subjects), although 60% of them provided medical record on previous dual measles vaccination occurred in childhood. Another cohort consisted of subjects who had medical record of measles vaccination in childhood (32 subjects), but lost protective measles antibodies produced by plasma cells (23 subjects), and memory T cells (3 subjects), or measles antibodies and memory B cells (6 subjects) over time. Such pattern evidences that measles-specific cellular and humoral arms immune responses were developed and maintained independently of each other.

Non-invasive detection of IgG antibodies from common pathogenic viruses using oral flocked swabs

Salivary antibodies are useful in surveillance and vaccination studies. However, low antibody levels and degradation by endonucleases are problematic. Oral flocked swabs are a potential non-invasive alternative for detecting viral antibodies. Seroprevalence for Cytomegalovirus (CMV), Varicella-Zoster virus (VZV), Epstein–Barr virus (EBV), Measles and Mumps IgG antibodies were determined from 50 matched serum, saliva and swabs samples from healthy volunteers using commercial ELISAs. CMV IgG, VZV IgG, and EBV EBNA-1 IgG, VCA IgG, and Measles IgG swab versus serum sensitivities were 95.8%, 96.0%, 92.1%, 95.5%, 84.5%, respectively, and swabs correlated well with saliva. Sensitivity of Mumps IgG in swabs and saliva was poor at 60.5%, and 68.2%, respectively. Specificities for IgG antibodies were 100% for CMV, EBV and Mumps, but could not be determined for VZV and Measles due to exclusively seropositive volunteers. Except for Mumps IgG, swabs correlate well with serum, are easy to self-collect and are stable at room temperature.

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.

Prevalence of measles IgG antibodies among immigrant workers in South Korea

Abstract Background After the national vaccination for measles was introduced in 1985, the measles has been controlled in South Korea despite the epidemic in 2000-2001. Current cases in Korea were assumed to be transmitted from outside the country. Because the dynamics and social changes of the population has emerged as important factors in the measles epidemic, this study aimed to assess the prevalence of measles IgG antibodies among immigrant workers. Methods The cross sectional seroprevalence survey was conducted in Gyeongsangnamdo province, Korea. Because the representative sampling frame could not be possible, the voluntary foreign workers who have agreed informed consents with a translated format into the native language, participated in this study. IgG antibodies of measles was examined by ELISA using the automation equipment (BEP III- ELISA). This study obtained the approval of Dong-A University Clinical Research Ethics Review Committee. Results 364 people of foreign workers participated in the study. Regional distribution for study participants was composed of 30 people in Vietnam (16.5%), Uzbekistan 71 people (19.5%), Thailand 70 people (19.2%), China 60 people (16.5%), Philippines 36 people (9.9%), and Indonesia 32 people (8.8%). The average age was 33.0 ± 6.9 years old and 86.5% of the total was men. High school or higher education accounted for 74%. 93.7% showed positivity (95% CI: 95.7-98.9%) for measles IgG antibody and 3.6% showed equivocal. Conclusions The measles seropositivity among immigrant workers in Korea was considered to be at the recommended level. Key messages The measles seropositivity among immigrant workers in Korea was considered to be at the recommended level. International cooperation is needed to prevent global measles epidemic.

Seroprevalence of Transplacentally acquired Measles antibodies in unvaccinated infants at nine months of age and its relation to the feeding practices

BackgroundIn recent years Pakistan has faced frequent measles outbreaks killing hundreds of children despite the availability of vaccine for decades. This study was undertaken to determine the persistence of maternal transferred measles antibody levels in infants before measles vaccination with relation to their feeding practices.MethodsA cross sectional study was conducted at district Islamabad over 1 year between 1st October 2013 to 30th Sept. 2016. Any infant less than 9 months of age, not suffering from an acute or debilitating illness and not vaccinated was enrolled in the study. After taking written informed consent from parents / guardians, information was collected on a pretested questionnaire. About 3 cc venous blood was taken to quantify any measles IgG antibodies. Data was analyzed by using Epi Info 7.2 version.ResultsThree hundred eighty-four infants were enrolled and were divided into three age groups, 1–90, 91–180 and 181–270 days age groups. Mean age of infants was 4.4 months ±3.2 SD. Male to female ratio was 1.2:1. A level of maternal measles IgG antibodies ≥12 U/ml was taken as protective. Of total 384 infants, 91(24%) had protective measles antibody titters (> 12 U/ml). and 65 (73%) of them were on breast milk. Highest antibody levels were found in 1–90 days age group. Analysis showed that 181–270 days aged infants had 3.1875 more odds of having unprotected/ low levels of antibodies against measles than children aged less than 180 days. Age group < 180 days found to be statistically significant with protective IgG levels (OR: 3.1875, P value: < 0.000063).ConclusionMeasles protective antibodies were found in infants < 180 days age group. Breast feeding provides early protection against measles. Levels drop down to low levels immediately after birth and then after 06 months. It is, therefore, recommended that measles vaccination should be considered for administration at 6 months or even earlier if measles immunity is desired.

Incidence of measles specific IgG antibody among children in Adamawa State, Nigeria

Measles account for nearly half of the 1.7 million annual deaths due to childhood vaccine- preventable diseases. Presence of measles specific IgG antibodies has been proven to correlate with protection (immunity) to natural measles infection. This study was therefore designed to determine the prevalence of measles specific IgG antibody and also to determine the association between prevalence of measles specific IgG antibody and age, gender, as well as history of measles infection among children aged 0-14 years in Adamawa State. The research was carried out within the three senatorial districts of the State. Serum samples (368) collected from children were used to determine the prevalence using ELISA method. Questionnaire was used to obtain demographic data of the children relevant to the study. The study revealed that 227 (61.6%) of the children had protective measles IgG antibody with antibody titre ranging from 10-250 U/mL, while 141 (38.4%) had non-protective measles IgG antibody. There was significant association between history of measles infection and protective antibodies (P-value=0.000), but there was no significant association between gender (P-value = 0.958), age (P- value = 0.140) and protective measles IgG antibody.

The application of measles specific IgM and IgG antibody detection in classification measles vaccine failure, Tianjin

Objective: To study the application of measles specific IgM and IgG antibody detection in classification of primary vaccination failure (PVF) and secondary vaccination failure (SVF). Methods: Measles surveillance information system was used to collect measles confirmed cases in Tianjin, 2013-2015, and their blood specimens were collected, totally 284 cases were enrolled. Measles IgM and IgG were detected with enzyme-linked immunosorbent assay (ELISA), and the relative avidity index (RAI) was used to express the result of measles avidity. Measles IgM, IgG and IgM/IgG was analyzed with receiver operating characteristic (ROC) curve, the area under the ROC curve (AUC) as evaluation indicators. In addition, compared with a measles outbreak (26 cases) of a middle school in Tianjin in 2016, for making further verification on the diagnostic value of vaccination failure with IgM, IgG and IgM/IgG. Results: The age of cases ranged was 0-58 years old, the interval median (P(25), P(75)) of serum collection after rash onset was 2 (1, 4) days. The positive rate of measles IgM and IgG in acute phase specimens were 76.06% (216 cases) and 88.38% (251 cases). According to the ROC curve analysis, the area under the ROC curve (AUC) of IgM, IgG and IgM/IgG were 0.753, 0.891 and 0.952, indicating that IgM/IgG was the best index to distinguish PVF and SVF. The best cut off value for IgM/IgG was 0.06, the sensibility and specificity were 88.75% and 86.63%. When IgM/IgG >1, 96.30% cases were low-avidity (RAI <40%), only 1 case was equivocal response (RAI: 40%-60%). 97.14% cases were high-avidity (RAI >60%) when IgM/IgG <0.01, only 3 cases were equivocal response (RAI 40%-60%). The threshold of IgM/IgG was used to verify the measles outbreak of a middle school in Tianjin, 2016. In the acute phase specimens, 100% (26 cases) of IgM/IgG were <0.06, 84.62% (22 cases) of IgM/IgG were <0.01. Conclusion: The detection of measles IgM and IgG with ELISA, and IgM/IgG is a valuable diagnostic tool to distinguish PVF and SVF.