Assessment of immunity to the measles virus through the detection of IgG antibodies

Epidemiology of a workplace measles outbreak dominated by modified measles cases at Kansai international airport, Japan, during august–september 2016

Human papillomavirus (HPV) and hepatitis B (HBV) vaccines are critical to cancer prevention strategies; however, achieving high vaccination coverage remains a challenge. We aimed to investigate the proportion of Canadian 14-year-old children who received these vaccines by child's gender and examine sociodemographic factors associated with vaccination. We used a cross-sectional design to analyse data from the 2021 Childhood National Immunization Coverage Survey. Data were collected using self-completed electronic questionnaires or telephone interviews. Parents/guardians of 14-year-old children separately reported their child's 1-dose HPV and 1-dose HBV vaccination status (categorised as vaccinated, unvaccinated or unknown vaccination status), and their sociodemographic characteristics. Univariable multinomial logistic regression models were used to calculate vaccination status by sociodemographic variables. After weights were applied, the final weighted sample size was 413 255 and 413 710 respondents for the HPV and HBV samples, respectively. Uptake of 1 dose of the HPV and HBV vaccines was 74.9% and 78.7%, respectively, with higher uptake in girls compared with boys for HPV (80.0% vs 69.9%) and HBV (80.9% vs 76.4%). Having more children in the home was associated with higher odds of being HPV unvaccinated. Less parent education, being born outside Canada, being a boy and having an Indigenous identity were associated with higher odds of an unknown HPV vaccination status. Older parent age and less parent education were associated with higher odds of being HBV unvaccinated. Less parent education and parents who were not married/common law were associated with higher odds of an unknown HBV vaccination status, while older parent age and residing in Quebec were associated with lower odds. HPV and HBV vaccination coverage in Canada did not reach national and global targets of 90% in 2021. This study highlights sociodemographic disparities in vaccine uptake, which were unique to each vaccine and vaccination status. These findings provide evidence of inequities that should be systematically monitored.

Objective To establish an indirect ELISA method for detection of measles virus antibody based on the nucleoprotein of measles virus expressed in prokaryotic system selected as the coating antigen. Methods The working conditions were screened and optimized to determine the operation process of indirect ELISA. The anti-measles virus IgG antibody in 157 sera of healthy children and mothers of newborn infants was detected and compared with the commercial measles virus ELISA IgG antibody detection kit. Results The result showed that the coefficient of variation of intra and inter assay repeatability of the indirect ELISA was less than 10%. Compared with the result of the commercial kit, the total concordance rate of serum samples was 95.5%, and the sensitivity and specificity were 94.8% and 98.3%, respectively. There was no significant difference between the two methods(χ2=0.313, P>0.05; χ2=0.000, P>0.05) in the positive rate of measles virus IgG antibody in 85 healthy children at the age of 0~15 years. The level of measles virus antibody detected by ELISA established in this study showed the same increasing and decreasing trend as that detected by the commercial kit in different age groups. The correlation coefficient r of the quantitative result was 0.893 (P< 0.001), which showed the quantitative potential of the method. Conclusions The ELISA method established in this study has good stability, high sensitivity and specificity, and there was no significant difference between the detection results of commercial kit and the ELISA method. It can be used for the seroepidemiological investigation of measles virus and the evaluation of antibody level of the population after vaccination. Key words: Measles virus; Nucleoprotein; Serology; Indirect ELISA

AIMS: The purpose of this study was to compare the performance of three automated immunoassays for the detection of IgM and IgG Toxoplasma gondii antibodies using sera of pregnant women living in Colombia, a Latin American country with a high seroprevalence. METHODS: A total of 905 sera were tested for IgM antibodies and 914 for IgG antibodies with AxSYM, VIDAS and VIDIA immunoassays. Discrepancies were resolved by using the dye test for IgG antibodies, and the ISAGA test for IgM. RESULTS: The overall agreement between AxSYM, VIDAS and VIDIA assays was excellent for detection of IgG and IgM antibodies, and discrepancies were relatively rare (3.6% and 5.5% of sera for IgG and IgM antibodies, respectively). The performance of the three immunoassays was similar for the detection of IgG antibodies with high sensitivity (100.00% for VIDIA, 99.59% for VIDAS, 99.38% for AxSYM) and specificity (99.04% for VIDIA, 98.82% for AxSYM, 98.57% for VIDAS). The specificity for IgM antibodies was excellent for the three immunassays (99.88% for VIDIA, 99.76% for AxSYM and VIDAS). The sensitivity of the detection of IgM antibodies was higher with VIDIA (95.12%) than with VIDAS (76.74%) and AxSYM (61.90%) assays. The correlation between IgG titers was limited between AxSYM and VIDAS assays and between AxSYM and VIDIA assays, but was excellent between VIDIA and VIDAS assays. CONCLUSIONS: Our study performed with Latin American sera confirmed the excellent specificity of AxSYM, VIDAS and VIDIA assays for the detection of IgG and IgM antibodies already reported in other countries. The sensitivity of the detection of IgG antibodies was slightly higher with VIDIA than with VIDAS and AxSYM assays. The sensitivity of the detection of IgM antibodies was higher with VIDIA than with VIDAS and AxSYM assays.

Measles is a highly contagious vaccine-preventable viral disease. Successful vaccination programs resulted in limited measles transmission in the United States in 2000, but U.S. cases have been increasing since early 2025. On May 20, 2025, CDC notified the Colorado Department of Public Health and Environment of a measles case in an unvaccinated, non-Colorado resident who had arrived in Denver, Colorado, on an international flight and traveled through the Denver International Airport while infectious. The patient acquired measles in the United States before travelling internationally. Nine secondary measles cases and one tertiary case associated with this traveler were confirmed among Colorado residents; seven additional cases were reported by other jurisdictions. Four of the nine secondary Colorado cases occurred among persons who had received 2 doses of measles, mumps, and rubella vaccine before exposure. Two of these vaccinated persons received negative measles reverse transcription-polymerase chain reaction (RT-PCR) test results from nasopharyngeal swab specimens and positive results from urine specimens. A third patient, with unknown measles vaccination status, received a positive urine RT-PCR test result 24 days after rash onset. Three unvaccinated patients and one with unknown vaccination status were hospitalized, and all recovered. All patients reported having a rash, but vaccinated patients reported fewer and milder symptoms overall. This outbreak highlights the importance of staying up to date with recommended vaccinations, especially before traveling. Routinely collecting urine specimens for measles testing could improve identification of cases and increase detection sensitivity, especially among previously vaccinated persons.

While a major reduction in morbidity and mortality from measles has been achieved in Qatar since it adopted the measles elimination programme in 1997, the country has experienced small, recurrent measles outbreaks. The aim of this study was to determine the demographical and epidemiological characteristics of measles cases reported to the surveillance programme in Qatar in 2007. Of 362 confirmed cases 67.7% were among children aged 1-14 years old and 16.9% were > 15 years. A majority of cases were unvaccinated (35.9%) or had unknown or undocumented vaccination status (47.0%). The high proportion of cases were among Pakistani nationals (39.5%) followed by Qataris (27.6%). Measles outbreaks were concentrated among the children of expatriates of Asian ethnicity with unknown vaccination status. This highlights the importance of achieving uniformly high levels of vaccination coverage in a community.

The indirect fluorescent antibody(IFA) test was used to detect serum IgG and IgM antibodies to Trichomonas vaginalis in 31 vaginal trichomoniasis, 7 candidiasis and in 20 non-infected healthy wonem with antigen prepared from axenic culture of Trichomonas vaginalis isolated from vulvovaginitis patient. The results were as follows: In 31 vaginal trichomoniasis the positive reactions of IgG antibody were 27 in the 1/8 dilution or higher and 4 in the 1/4 dilution whereas in healthy women the reaction showed signigicantly low as in the 1/4 dilution of below. The sensitivity and specificity of IFA test for IgG antibody to trichomonad antigen in this study were 87.1% and 100%, respectively. No significant difference of IgM antibody levels between vaginal trichomoniasis and healthy women was observed. No relation between the levels of IgG and IgM antibodies to trichomonad antigen by IFA test was observed. No relation between the time lapse and the level of serum IgG antibodies in IFA test of vaginal trichomoniasis was regarded. In conclusion the present study suggests that IFA test in trichomoniasis could be a useful tool for detection of anti-trichomonad IgG antibodies and applicable as an immundiagnostic method.

Measles: A continuing saga

A solid-phase radioimmunoassay (RIA) was used to determine the presence of IgG and IgM antibodies to measles virus in human serum and cerebrospinal fluid (CSF). Purified measles virus was adsorbed on to polystyrene balls, which were then exposed to serial dilutions of test serum or CSF. The presence of antibody was measured by its capacity to bind 125I-labelled specific anti-human IgG or IgM. Serum from a variety of patients as well as measles-immune clinically healthy persons were tested; binding ratios (using negative human serum controls) were usually between 10 and 30, but with subacute sclerosing panencephalitis (SSPE) ratios were as high as 50. Of ten CSF specimens tested, all but one, which was taken early in the convalescent phase of measles infection, had detectable IgG antibody. In six patients with acute measles, IgM antibodies were found in all serum specimens taken one or more days after the onset of rash. Maximal titers of 1:10000 to 1:40000 were found about 7 days later. Thereafter, IgM titres decreased rapidly but were still detectable at 40 days. A purified ribonucleoprotein of measles virus was also used successfully as an antigen in this RIA method.

Measles virus (MV) causes small and large outbreaks in Iran. Molecular assays allow identifying and the sources of measles imported from neighboring countries. We carried out a phylogenetic analysis of measles virus circulating in Iran over the period 2010–2012. Specimens from suspected cases of measles were collected from different regions of Iran. Virus isolation was performed on urine and throat swabs. Partial nucleoprotein gene segments of MV were amplified by RT-PCR. PCR products of 173 samples were sequenced and analyzed. The median age of confirmed cases was 2 years. Among all confirmed cases, 32% had unknown vaccination status, 20% had been vaccinated, and 48% had not been vaccinated. Genotypes B3 and D8 (for the first time), H1 and D4 were detected mainly in unvaccinated toddlers and young children. Genotype B3 became predominant in 2012 and was closely related to African strains. H1 strains were also found in small and large outbreaks during 2012 but were not identical to Iranian H1-2009 strains. A majority of the Iranian D4 strains during 2010–2012 outbreaks were linked to the D4 strain identified in the Pakistan in 2007. We identified a single case in 2010 belonging to D8 genotype with 99.7% identity to Indian isolates. Although the vaccination program is currently good enough to prevent nationwide epidemics and successfully decreased measles incidence in Iran, the fraction of protected individuals in the population was not high enough to prevent continuous introduction of cases from abroad. Due to increasing number of susceptible individuals in some areas, sustained transmission of the newly introduced viral genotype remains possible.

Transplacental HCV-antibodies circulate in the blood of infants during the first year of the life and diagnosis of HCV-transmission is difficult. Aim: to study informativeness of serological diagnostic tests in anti/HCV-positive infants. Material and methods. the study was conducted in two groups of infants: RNA-positive (n=28) and RNA-negative (n=277). All children were born from a pregnant woman with chronic viral hepatitis C. The authors determined the sensitivity, specificity and accuracy of serological diagnostic tests for HCV transmission in infants: anti/HCV total, anti-HCcore IgG, anti-HCcore IgM, anti-HCNS3 IgG, anti-HCNS3 IgМ, anti-HCNS4 IgG, anti-HCNS4 IgМ, anti-HCNS5 IgG, anti-HCNS5 IgМ. Results. Detection of anti-HCV IgG-antibodies in the first 9 months of a child’s life has a high sensitivity but low specificity and low diagnostic efficacy; detection of anti HCV-IgM antibodies in the blood of the infant has significant specificity and high diagnostic efficacy. Discussion. The terms of examination of infants for viral hepatitis C are regulated by Sanitary Regulations and Standards (SanPiN 3.1.3112-13 Prevention of viral hepatitis C). We found that the detection of IgG antibodies in the blood of infants who were born to HCV-positive women has low diagnostic efficacy and will not lead to a correct diagnosis of perinatal HCV- transmission. It is necessary to develop and make changes in sanitary epidemiological rules. Conclusion. detection IgG-antibody is not informative during the first half of the infant’s life, but detection IgM-antibody is highly specific and accurate serological test for diagnostic HCV-transmission to child from mother with chronic viral hepatitis C.

Transplacental HCV-antibodies circulate in the blood of infants during the first year of the life and diagnosis of HCV-transmission is difficult. Aim: to study informativeness of serological diagnostic tests in anti/HCV-positive infants. Material and methods. the study was conducted in two groups of infants: RNA-positive (n=28) and RNA-negative (n=277). All children were born from a pregnant woman with chronic viral hepatitis C. The authors determined the sensitivity, specificity and accuracy of serological diagnostic tests for HCV transmission in infants: anti/HCV total, anti-HCcore IgG, anti-HCcore IgM, anti-HCNS3 IgG, anti-HCNS3 IgМ, anti-HCNS4 IgG, anti-HCNS4 IgМ, anti-HCNS5 IgG, anti-HCNS5 IgМ. Results. Detection of anti-HCV IgG-antibodies in the first 9 months of a child’s life has a high sensitivity but low specificity and low diagnostic efficacy; detection of anti HCV-IgM antibodies in the blood of the infant has significant specificity and high diagnostic efficacy. Discussion. The terms of examination of infants for viral hepatitis C are regulated by Sanitary Regulations and Standards (SanPiN 3.1.3112-13 Prevention of viral hepatitis C). We found that the detection of IgG antibodies in the blood of infants who were born to HCV-positive women has low diagnostic efficacy and will not lead to a correct diagnosis of perinatal HCV- transmission. It is necessary to develop and make changes in sanitary epidemiological rules. Conclusion. detection IgG-antibody is not informative during the first half of the infant’s life, but detection IgM-antibody is highly specific and accurate serological test for diagnostic HCV-transmission to child from mother with chronic viral hepatitis C.

In 2017, the WHO registered 23,927 measles cases in 44 out of 53 countries in the European region. In 2018, measles incidence rate increased up to 82,599 cases registered in 48 countries of the region, with a large number of measles-associated deaths. Overall, 72 measles fatalities were registered in 10 European countries, including Serbia (15 cases).Aim of the study: to characterize 2017—2018 epidemiological upsurge of measles incidence rate observed in the Republic of Serbia (RS) and the Northwestern Federal District (NWFD) of the Russian Federation.Materials and methods. During the 2017—2018 season, 944 serum samples were collected from patients with measles, rubella, or exanthematous diseases in the NWFD and tested in the Laboratory of Virology at the St. Petersburg Regional Centre for Measles Surveillance (SPbRC). In 2017—2018, 2,946 serum samples from the Republic of Serbia were analyzed in the SPbRC by using ELISA with IgM measles test system (Vector-Best, Russia; or Siemens, Germany). Urine and swab samples were examined by RT-PCR and used for isolation and genotyping of measles viruses.Results. From 2017 to 2018, 5,798 measles cases were registered in the RS, among which 2,946 were laboratory-confirmed (serological testing and/or PCR). Unvaccinated subjects or those with unknown vaccination status accounted for majority of the cases. Children under 5 years of age and adults aged 30 years and over dominated among measles patients. During this season, 15 deaths were reported. Several genotypes of measles virus circulated in the RS, e.g. В3 Dublin, D8 Gir Somnath, and D8 Herborn. In 2018, 109 measles cases were recorded in the NWFD, 5 of which were imported from abroad. Among patients, adults comprised 64.2%, wherein 74.3% were covered by unvaccinated subjects or those with unknown vaccination status. Rise in measles incidence rate linked to multiple importations of various measles virus genotypes: В3 Kabul; B3 Dublin; D8 Frankfurt; D8 Cambridge; and D8 Gir Somnath.

Oral fluids for the immunodiagnosis of Schistosoma mansoni infection

BackgroundAs China approaches the elimination of measles, outbreaks of measles continue to occur. Healthcare workers (HCWs) are known to be at high risk of infection and transmission of measles virus. A measles outbreak occurred in a hospital in Xinjiang Uighur Autonomous Region of the People’s Republic of China. We report an investigation of this outbreak and its implications for measles elimination and outbreak preparedness.MethodsWe conducted a retrospective search for measles cases using hospital records. Information on cases was collected by interview, and was used to determine epidemiological linkages. We surveyed HCWs to determine their demographic characteristics, disease history and vaccination status, and knowledge about measles.ResultsWe identified 19 cases, ages 18 to 45 years, in Hospital W between December 2015 and January 2016; 14 were laboratory-confirmed, and 5 were epidemiologically linked. The primary case was a 25-year-old neurology department nurse who developed a rash on 22 December 2015 that was reported on 11 January 2016. She continued working and living with her workmates in a dormitory during her measles transmission period. Among the 19 infected HCWs, 2 had received a dose of measles-containing vaccine (MCV) before the outbreak, and 16 had unknown vaccination status. Outbreak response immunization activities were started on 8 January in a non-selective manner by offering vaccine regardless of vaccination history; 605(68%) of 890 HCWs were vaccinated. The HCW survey had a 73% response rate (646/890); 41% of HCWs reported that they had received MCV before outbreak, and 56% exhibited good knowledge of measles symptoms, transmission, complications, and vaccination.ConclusionsLow MCV coverage, low measles knowledge among HCWs, delayed reporting of measles cases, and absence of proper case management were associated with this outbreak. Training and vaccinating HCWs against measles are essential activities to prevent measles virus transmission among HCWs.