Measles Antibody Levels Research Articles

Correlations among measles virus-specific antibody, lymphoproliferation and Th1/Th2 cytokine responses following measles–mumps–rubella-II (MMR-II) vaccination

Immunity to measles is conferred by the interplay of humoral and cellular immune responses, the latter being critical in maintaining long-term recall response. Therefore, it is important to evaluate measles-specific humoral and cellular immunity in populations several years after vaccination and understand the correlations among these measures of immunity. We examined measles-specific antibodies, lymphoproliferation and the Th1/Th2 signature cytokines, interferon (IFN)-gamma and interleukin (IL)-4, in a population-based cohort of healthy children from Olmsted County, Minnesota after two doses of measles-mumps-rubella-II (MMR-II) vaccine. We detected positive measures of measles-specific cellular and humoral immunity in the majority of our study population. However, a small proportion of subjects demonstrated an immune response skewed towards the Th2 type, characterized by the presence of either IL-4 and/or measles-specific antibodies and a lack of IFN-gamma production. Further, we observed a significant positive correlation between lymphoproliferation and secretion of IFN-gamma (r = 0.20, P = 0.0002) and IL-4 (r = 0.15, P = 0.005). Measles antibody levels were correlated with lymphoproliferation (r = 0.12, P = 0.03), but lacked correlation to either cytokine type. In conclusion, we demonstrated the presence of both long-term cellular and humoral responses after MMR-II vaccination in a significant proportion of study subjects. Further, a positive correlation between lymphoproliferation and IL-4 and IFN-gamma suggests that immunity to measles may be maintained by both Th1 and Th2 cells. We speculate that the Th2 biased response observed in a subset of our subjects may be insufficient to provide long-term immunity against measles. Further examination of the determinants of Th1 versus Th2 skewing of the immune response and long-term follow-up is needed.

Extinction of the Human Leukocyte Antigen Homozygosity Effect After Two Doses of the Measles-Mumps-Rubella Vaccine

We have reported associations between human leukocyte antigen (HLA) homozygosity and low measles antibody levels after one dose of the measles, mumps, and rubella (MMR) vaccine. Here, we examined associations between HLA homozygosity and immune responses to MMR after two doses of vaccine. We examined associations between HLA homozygosity and measles antibody levels in a group of 178 children (cohort 1) as well as associations between homozygosity and antibody levels and lymphoproliferative responses to MMR in 346 children (cohort 2). In cohort 1, HLA homozygotes and heterozygotes had similar increases in measles antibody levels after a second dose of measles vaccine. In cohort 2, HLA homozygosity was not associated with measles immune measures after two doses of vaccine. Homozygosity at the DPB locus was associated with increased rubella antibody levels, and homozygosity at the class IA alleles was associated with lower mumps lymphoproliferative response. Homozygosity at increasing numbers of loci was also associated with lower mumps antibody levels and lymphoproliferative response. Therefore, two doses of the MMR vaccine appear to induce sufficient antibody levels and lymphoproliferative responses against measles and rubella, regardless of HLA homozygosity status. However, children who are HLA homozygous may be less protected against mumps compared with children who are heterozygous.

Neonatal Measles Immunity in Rural Kenya: The Influence of HIV and Placental Malaria Infections on Placental Transfer of Antibodies and Levels of Antibody in Maternal and Cord Serum Samples

Young infants are protected from measles infection by maternal measles antibodies. The level of these antibodies at birth depends on the level of antibodies in the mother and the extent of placental transfer. We investigated predictors of levels of measles antibodies in newborns in rural Kenya. A total of 747 paired maternal-cord serum samples (91 from human immunodeficiency virus [HIV]-infected and 656 from HIV-uninfected mothers) were tested for measles immunoglobulin G antibodies. Placental malaria infection was determined by biopsy. Data on pregnancy history, gestational age, and anthropometric and socioeconomic status were collected. Infants born to HIV-infected mothers were more likely (odds ratio, 4.6 [95% confidence interval {CI}, 2.2-9.7]) to be seronegative and had 35.1% (95% CI, 9.8%-53.2%) lower levels of measles antibodies than did those born to HIV-uninfected mothers. Preterm delivery, early maternal age, and ethnic group were also associated with reduced levels of measles antibodies. There was little evidence that placental malaria infection was associated with levels of measles antibodies in newborns. Our results suggest that maternal HIV infection may reduce levels of measles antibodies in newborns. Low levels of measles antibodies at birth render children susceptible to measles infection at an early age. This is of concern in sub-Saharan African countries, where not only is the prevalence of HIV high, but measles is the cause of much morbidity and mortality.

Macular Retinitis as a First Sign of Subacute Sclerosing Panencephalitis: The Importance of Early Diagnosis

Purpose: Subacute sclerosing panencephalitis (SSPE) is a subacute inflammatory and neurodegenerative encephalitis related to the measles (rubeola) virus and usually affecting children and young adults. The overwhelming majority of cases follow a progressive downhill course leading to death, although there have been a few case reports of patients who have apparently gone into remission. Ocular changes occur in up to 50% of SSPE cases. Visual complaints, if present, generally antedate the onset of neurological symptoms by a few weeks or months. Here, we report two cases of SSPE presenting with ocular findings and their prognoses. Methods: Case reports. In the first case, a 17-year-old male presenting with macular retinitis, the macular findings were mistaken for a heredodegenerative disorder and diagnosis was postponed until neurological findings took place. He died six months after the appearance of his first ophthalmic symptoms despite intravenous immune globulin and isoprinosine therapy. The second case was a 14-year-old male, who presented with only ophthalmological complaints. His diagnosis was based on both ophthalmological findings and high doses of measles IgG in the cerebrospinal fluid (CSF); isoprinosine and intramuscular beta-interferon therapy was started before the onset of neurological findings and in the follow-up time of about 18 months, neurological findings consistent with SSPE did not develop. Results: The characteristic finding of macular retinitis in SSPE patients is rapid recovery in about one month without therapy. After improvement, neurological findings take place. Once suspected, the diagnosis of SSPE is easily established by the demonstration of high levels of measles antibody in the serum and CSF. Early diagnosis can be made with typical ocular findings and high IgG titers for rubeola in CSF. Conclusion: We suppose that ophthalmic manifestations, especially macular retinitis, may be useful in the diagnosis and management of SSPE cases with elevated IgG titers for rubeola in CSF. The typical clinical findings must be familiar to every ophthalmologist so that diagnostic pitfalls can be prevented and early therapy started. It may be discussed if early diagnosis and therapy will be possible before neurological signs appear, the prognosis of this relentless disease may show a more favorable course.

Associations between human leukocyte antigen (HLA) alleles and very high levels of measles antibody following vaccination

Associations between human leukocyte antigen (HLA) genes and very high levels of antibodies (or hyperseroresponsiveness) to measles antigens in a genetically heterogeneous human population are poorly understood. We studied the association between antibody levels after measles vaccination and HLA class I and II alleles among 170 US schoolchildren who received one dose of measles-mumps-rubella II vaccine. Vaccine recipients were divided into two groups: 93 recipients who were seropositive and 77 recipients who were hyperseropositive (the upper 10th percentile of antibody levels of all subjects). Out of all the alleles analyzed, HLA-B ∗7 (odds ratio (OR) 1.9; P=0.05), DQA1 ∗0104 (OR 4.6; P=0.02) and DPA1 ∗0202 (OR 4.8; P=0.04) alleles were positively associated with hyperseropositivity, whereas HLA-B ∗44 (OR 0.4; P=0.02), DRB1 ∗01 (OR 0.6; P=0.09), DRB1 ∗08 (OR 0.3; P=0.04), DQB1 ∗0301 (OR 0.5; P=0.04), and DPB1 ∗0401 (OR 0.6; P=0.03) alleles were negatively associated with hyperseropositivity. The alleles B ∗44, DRB1 ∗01, DRB1 ∗08 and DQA1 ∗0104 remained statistically significant after accounting for the effects of other alleles. The results suggest that HLA alleles have important associations with measles antibody hyperseropositivity. These data increase our understanding of measles vaccine-induced immune response and will be useful for future mechanistic work on measles virus antigen processing and presentation in seronegative and hyperseropositive individuals.

Associations between human leukocyte antigen (HLA) alleles and very high levels of measles antibody following vaccination

Associations between human leukocyte antigen (HLA) genes and very high levels of antibodies (or hyperseroresponsiveness) to measles antigens in a genetically heterogeneous human population are poorly understood. We studied the association between antibody levels after measles vaccination and HLA class I and II alleles among 170 US schoolchildren who received one dose of measles-mumps-rubella II vaccine. Vaccine recipients were divided into two groups: 93 recipients who were seropositive and 77 recipients who were hyperseropositive (the upper 10th percentile of antibody levels of all subjects). Out of all the alleles analyzed, HLA-B ∗ 7 (odds ratio (OR) 1.9; P =0.05), DQA1 ∗ 0104 (OR 4.6; P =0.02) and DPA1 ∗ 0202 (OR 4.8; P =0.04) alleles were positively associated with hyperseropositivity, whereas HLA-B ∗ 44 (OR 0.4; P =0.02), DRB1 ∗ 01 (OR 0.6; P =0.09), DRB1 ∗ 08 (OR 0.3; P =0.04), DQB1 ∗ 0301 (OR 0.5; P =0.04), and DPB1 ∗ 0401 (OR 0.6; P =0.03) alleles were negatively associated with hyperseropositivity. The alleles B ∗ 44, DRB1 ∗ 01, DRB1 ∗ 08 and DQA1 ∗ 0104 remained statistically significant after accounting for the effects of other alleles. The results suggest that HLA alleles have important associations with measles antibody hyperseropositivity. These data increase our understanding of measles vaccine-induced immune response and will be useful for future mechanistic work on measles virus antigen processing and presentation in seronegative and hyperseropositive individuals.

Site-directed serology of HIV-1 subtype B infection: relation between virus specific antibody levels and disease progression

Activated T helper (Th) cell-dependent (TD) antibody responses were determined over an 8-10 year period in 28 patients infected with HIV-1 subtype B. Twelve patients remain asymptomatic with normal CD4+ cell counts for 101-114 months. These individuals were defined as long-term asymptomatic (LTA). Sixteen patients progressed to severe immunodeficiency within 58-120 months. In samples derived close to the diagnosis of HIV-1, CD4+ cell counts were higher among the LTAs (P < 0.01). Antibody production driven by activated Th cells was determined using peptides corresponding to HIV-1 V3US/Eur, gp41, and the hepatitis C virus (HCV) core proteins. The less Th cell-dependent B cell antibody response was represented by measles virus immunity. Close to HIV-1 diagnosis, variable third (V3), gp41, HCV core, and measles antibody titres were at similar levels among the LTAs and the progressors. With time the LTAs displayed unchanged levels of V3 and gp41 antibodies, and slightly decreasing levels of HCV core antibodies (P < 0.05). In contrast, the progressors showed a decrease in all these antibody responses (P < 0.05, for all). In both groups, the levels of measles antibody remained stable. Our data show that no significant change of the antibody responses of LTAs is seen, even after 101-114 months of known HIV-1 infection. Furthermore, the marked decrease of TD antibody production in the progressors suggests that activated Th cells may be excellent targets for HIV-1 infection.

H1 genotype of measles virus was detected in outbreaks in Japan after 2000.

We investigated the molecular epidemiology and biological characteristics of wild measles viruses isolated since 1984 in Japan. The circulating measles virus was of genotype C1 before 1985, D3 from 1987 to 1990, and D5 from 1990 to 1997. It was replaced by the same cluster of Chicago-type D3 strain from 1997 to 1999. In 2000, D5 recirculated with sporadic cases caused by genotype H1. The H1 genotype became dominant in 2001 with a minor distribution of D5. No significant difference was observed in neutralizing titers against C1, D3, D5, and H1 when we used sera having high neutralizing titers. However, some D3 and H1 strains were not completely neutralized with low levels of neutralizing antibody, and maintaining high levels of measles antibodies would be required for the control measles outbreaks.

Progress toward measles elimination in Romania after a mass vaccination campaign and implementation of enhanced measles surveillance.

In response to an outbreak of >33,000 measles cases in 1996-1998 and to prevent an outbreak predicted for 2002, Romania conducted a nationwide measles-rubella vaccination campaign in October 1998. Some 2.1 million children aged 7-18 years were vaccinated. Data from national surveillance and seroprevalence studies conducted in three districts were used to assess the campaign and status of measles control. Surveillance data showed a dramatic drop in measles despite enhanced surveillance starting in October 1999. From October 1999 to December 2001, 400 suspected measles cases were reported, down from about 5000 cases annually in non-outbreak years. Only 29 (8%) of 386 cases with specimens were laboratory confirmed; 14 were clinically confirmed. Seroprevalence estimates showed high measles antibody levels before (92.9%) and after (94.4%) the campaign. The low number of laboratory-confirmed cases and high population immunity suggest that interruption of indigenous measles virus transmission is a real possibility for Romania.

Associations between measles antibody levels and the protein structure of class II human leukocyte antigens

In this study, we describe associations between variation in human leukocyte antigen (HLA) DP and DQ amino acid sequences and low measles antibody levels after measles immunization. We tested serum samples from 242 children for measles immunoglobulin G antibodies. We performed class II HLA typing and examined associations between DQ and DP exon 2 amino acid sequences and antibody levels. No DP amino acid variants were associated with seronegativity. However, 11 DQA and 6 DQB amino acid variants were associated with seronegativity ( p < 0.005). These amino acid variants were highly correlated, and the significant DQA amino acids were only found in alleles *0201, *0301, *0401, *0501, and *0601. Two of the amino acids associated with measles seronegativity were located in predicted binding pockets of the DQ molecule; one was present in the leader sequence. Among the DQB alleles, all of the amino acid variants associated with seronegativity were present only in the DQB*0201 allele. Two of the amino acids associated with seronegativity were located in predicted binding pockets of the DQ molecule; two were located in the leader sequence. Our data suggest that specific DQA and DQB amino acid variations are associated with measles seronegativity after vaccination.

Cytokine production patterns and antibody response to measles vaccine

Cytokines play an important role in the immune response to live measles virus immunization. To gain further insight into the cytokine production profile in response to measles vaccination, we studied interferon-gamma (IFN-γ), tumor necrosis factor (TNF-α), soluble IL-2 receptor (sIL-2R), interleukin-2 (IL-2), interleukin-4 (IL-4), and interleukin-6 (IL-6) in both supernatants from peripheral blood mononuclear cells (PBMC) stimulated with phytohaemagglutinin (PHA), and plasma. We enrolled 57 healthy infants and children residing in an area where no measles virus circulated in their lifetimes. Overall analysis of cytokines in supernatants from PBMC showed that a predominant Th1 cytokine pattern occurs after the second dose of measles immunization. However, plasma levels of Th1 cytokines (IFN-γ, sIL-2R and TNF-α) were preferentially activated by measles virus after the first dose of measles vaccination. Median IFN-γ plasma levels were 1.73pg/ml for infants compared to 0.63pg/ml for older children (P=0.003). These data suggest that after the first and the second dose of measles virus immunization, there is a predominant Th1-type directed immune response, but the Th1 cytokine pattern seems to be stronger in previously unvaccinated children. There was no correlation between cytokine production by PBMC supernatants after PHA stimulation and circulating levels of plasma cytokines. No relationship was found between any specific cytokine level and measles antibody level.

Elevated levels of measles antibodies in children with autism

Virus-induced autoimmunity may play a causal role in autism. To examine the etiologic link of viruses in this brain disorder, we conducted a serologic study of measles virus, mumps virus, and rubella virus. Viral antibodies were measured by enzyme-linked immunosorbent assay in the serum of autistic children, normal children, and siblings of autistic children. The level of measles antibody, but not mumps or rubella antibodies, was significantly higher in autistic children as compared with normal children ( P = 0.003) or siblings of autistic children ( P ≤ 0.0001). Furthermore, immunoblotting of measles vaccine virus revealed that the antibody was directed against a protein of approximately 74 kd molecular weight. The antibody to this antigen was found in 83% of autistic children but not in normal children or siblings of autistic children. Thus autistic children have a hyperimmune response to measles virus, which in the absence of a wild type of measles infection might be a sign of an abnormal immune reaction to the vaccine strain or virus reactivation.

Abnormal Measles-Mumps-Rubella Antibodies and CNS Autoimmunity in Children with Autism

Autoimmunity to the central nervous system (CNS), especially to myelin basic protein (MBP), may play a causal role in autism, a neurodevelopmental disorder. Because many autistic children harbor elevated levels of measles antibodies, we conducted a serological study of measles-mumps-rubella (MMR) and MBP autoantibodies. Using serum samples of 125 autistic children and 92 control children, antibodies were assayed by ELISA or immunoblotting methods. ELISA analysis showed a significant increase in the level of MMR antibodies in autistic children. Immunoblotting analysis revealed the presence of an unusual MMR antibody in 75 of 125 (60%) autistic sera but not in control sera. This antibody specifically detected a protein of 73–75 kD of MMR. This protein band, as analyzed with monoclonal antibodies, was immunopositive for measles hemagglutinin (HA) protein but not for measles nucleoprotein and rubella or mumps viral proteins. Thus the MMR antibody in autistic sera detected measles HA protein, which is unique to the measles subunit of the vaccine. Furthermore, over 90% of MMR antibody-positive autistic sera were also positive for MBP autoantibodies, suggesting a strong association between MMR and CNS autoimmunity in autism. Stemming from this evidence, we suggest that an inappropriate antibody response to MMR, specifically the measles component thereof, might be related to pathogenesis of autism.

Abnormal measles-mumps-rubella antibodies and CNS autoimmunity in children with autism.

Autoimmunity to the central nervous system (CNS), especially to myelin basic protein (MBP), may play a causal role in autism, a neurodevelopmental disorder. Because many autistic children harbor elevated levels of measles antibodies, we conducted a serological study of measles-mumps-rubella (MMR) and MBP autoantibodies. Using serum samples of 125 autistic children and 92 control children, antibodies were assayed by ELISA or immunoblotting methods. ELISA analysis showed a significant increase in the level of MMR antibodies in autistic children. Immunoblotting analysis revealed the presence of an unusual MMR antibody in 75 of 125 (60%) autistic sera but not in control sera. This antibody specifically detected a protein of 73-75 kD of MMR. This protein band, as analyzed with monoclonal antibodies, was immunopositive for measles hemagglutinin (HA) protein but not for measles nucleoprotein and rubella or mumps viral proteins. Thus the MMR antibody in autistic sera detected measles HA protein, which is unique to the measles subunit of the vaccine. Furthermore, over 90% of MMR antibody-positive autistic sera were also positive for MBP autoantibodies, suggesting a strong association between MMR and CNS autoimmunity in autism. Stemming from this evidence, we suggest that an inappropriate antibody response to MMR, specifically the measles component thereof, might be related to pathogenesis of autism.

Associations between human leukocyte antigen homozygosity and antibody levels to measles vaccine.

The association between human leukocyte antigen (HLA) homozygosity and measles antibody levels was assessed in a volunteer group of 242 children. Serum samples were tested for measles IgG antibodies, class I and class II HLA alleles were typed, and associations were examined between HLA homozygosity and antibody levels. Children who were homozygous for at least 1 locus were twice as likely to be seronegative (odds ratio, 1.97; 95% confidence interval, 1.08-3.61). Children who were homozygous at >/=1 loci were increasingly likely to be seronegative (chi(2) test for trend; P=.02). When serum antibody levels were examined as continuous variables, children who were homozygous at certain loci tended to have lower mean antibody levels. These results suggest that lack of HLA diversity may limit the range of peptides that can be presented to antibody-producing cells, potentially resulting in a decreased immune response to viral infections.

Effect of Differing Immunization Policies on Circulating Measles Antibody Levels in US and Canadian Children

Objective To examine the effect of differing age-at- immunization policies on measles antibody levels in US children immunized at the age of 15 months compared with Canadian children immunized at the age of 12 months. Subjects and Methods Healthy, volunteer US and Canadian children aged 6 to 11 years who had been immunized with a single dose of the measles vaccine were enrolled from 1991 to 1993. Measles antibody was measured with a whole-virus, measles-specific IgG enzyme-linked immunoassay. Age, race, sex, country of residence, general health status, age at time of measles immunization, and time from immunization to sampling were recorded. Results Of the 1052 children enrolled in the study, US children (n=719) had a significantly higher measles sero- prevalence (87%) compared with Canadian children (n=333) (76%; P<.001). After adjustment for time from immunization and age at immunization, the differences in seropositive rates were no longer significant (odds ratio [OR], 1.53; 95% confidence interval, 0.87–2.69; P=.15). We found a significant dose-response relationship between age at the time of immunization and the odds of being seropositive after immunization, with ORs varying from 1 with immunization at 13 months or younger to 2.30 with immunization at 16 months of age (P=.01). Conclusions The current US policy of immunizing with the first dose of measles at the age of 12 months may be less effective than a policy of immunizing at 12 to 15 months of age. These findings may be highly significant as we move toward an era in which measles exposure may be rare and policies are developed to eradicate measles. To examine the effect of differing age-at- immunization policies on measles antibody levels in US children immunized at the age of 15 months compared with Canadian children immunized at the age of 12 months. Healthy, volunteer US and Canadian children aged 6 to 11 years who had been immunized with a single dose of the measles vaccine were enrolled from 1991 to 1993. Measles antibody was measured with a whole-virus, measles-specific IgG enzyme-linked immunoassay. Age, race, sex, country of residence, general health status, age at time of measles immunization, and time from immunization to sampling were recorded. Of the 1052 children enrolled in the study, US children (n=719) had a significantly higher measles sero- prevalence (87%) compared with Canadian children (n=333) (76%; P<.001). After adjustment for time from immunization and age at immunization, the differences in seropositive rates were no longer significant (odds ratio [OR], 1.53; 95% confidence interval, 0.87–2.69; P=.15). We found a significant dose-response relationship between age at the time of immunization and the odds of being seropositive after immunization, with ORs varying from 1 with immunization at 13 months or younger to 2.30 with immunization at 16 months of age (P=.01). The current US policy of immunizing with the first dose of measles at the age of 12 months may be less effective than a policy of immunizing at 12 to 15 months of age. These findings may be highly significant as we move toward an era in which measles exposure may be rare and policies are developed to eradicate measles.

Effect of Differing Immunization Policies on Circulating Measles Antibody Levels in US and Canadian Children

To examine the effect of differing age-at-immunization policies on measles antibody levels in US children immunized at the age of 15 months compared with Canadian children immunized at the age of 12 months. Healthy, volunteer US and Canadian children aged 6 to 11 years who had been immunized with a single dose of the measles vaccine were enrolled from 1991 to 1993. Measles antibody was measured with a whole-virus, measles-specific IgG enzyme-linked immunoassay. Age, race, sex, country of residence, general health status, age at time of measles immunization, and time from immunization to sampling were recorded. Of the 1052 children enrolled in the study, US children (n=719) had a significantly higher measles seroprevalence (87%) compared with Canadian children (n=333) (76%; P<.001). After adjustment for time from immunization and age at immunization, the differences in seropositive rates were no longer significant (odds ratio [OR], 1.53; 95% confidence interval, 0.87-2.69; P=.15). We found a significant dose-response relationship between age at the time of immunization and the odds of being seropositive after immunization, with ORs varying from 1 with immunization at 13 months or younger to 2.30 with immunization at 16 months of age (P=.01). The current US policy of immunizing with the first dose of measles at the age of 12 months may be less effective than a policy of immunizing at 12 to 15 months of age. These findings may be highly significant as we move toward an era in which measles exposure may be rare and policies are developed to eradicate measles.

Association of Parental Vaccination Reports With Measles, Mumps, and Rubella Protective Antibody Levels: Comparison of Somali Immigrant, Hispanic Migrant, and US Children in Rochester, Minn

To compare measles, mumps, and rubella antibody levels in Somali immigrant, Hispanic migrant, and US children in Rochester, Minn, and to determine whether parental vaccination reports predict seropositivity. From 1995 to 1997, we conducted a cross-sectional analysis using measles, mumps, and rubella antibody levels obtained from a sample of Somali, Hispanic, and Rochester children. Volunteers provided blood samples, vaccination histories, and demographic information. We assessed differences in measles, mumps, and rubella antibody levels among the 3 groups of children and calculated positive and negative predictive values to determine whether parental report of vaccination predicted seropositivity. Study participants included 79 Hispanic migrant, 69 Somali immigrant, and 730 Rochester children. Somali children reported vaccination at significantly older ages compared with Hispanic or Rochester children (P<.001). Most children were seropositive for all 3 antibodies. Parental reports of vaccination had high positive predictive values (71%-100%) but low negative predictive values (0%-50%). Somali and Hispanic children were as likely as Rochester children to be seropositive for measles, mumps, and rubella antibodies despite poor documentation of vaccination. Somali children, however, tended to receive vaccinations at significantly older ages than Hispanic and Rochester children.

Optimal age for vaccination against measles in the State of São Paulo, Brazil, taking into account the mother’s serostatus

In order to investigate if the changing levels of measles antibody in women resulting from extensive vaccination programs influence the susceptibility of children, we measured the seroprevalence of measles virus antibody of children in the first year of life and of their mothers. We compared maternal antibody decay of two groups of children: those whose mothers were 25 years old or more (mothers born in the pre-vaccination era), and less than 25 years old (mothers born in the vaccination era). Therefore, the 25-year-age cut-off was chosen to distinguish between vaccinated and non-vaccinated mothers. We also compared the immunogenicity of measles vaccine in children from 6 to 12 months of age, in these two groups and also according to their mother’s serostatus. The optimal age of vaccination for a routine program was estimated by means of mathematical models. This study was carried out in a sample of 1216 mothers and their respective children. Our results indicate that the optimal age for vaccination of the whole sample was 15 months, 17 months for children born from older mothers, 14 months for children born from younger mothers, 17 months for children born from seropositive mothers and 12 months for children born from seronegative mothers. Therefore, a change to an earlier age of routine vaccination is not justified by our results.

Influence of placental malaria infection and maternal hypergammaglobulinaemia on materno-foetal transfer of measles and tetanus antibodies in a rural west African population.

Placental malaria infection jeopardizes pregnancy outcome, and its influence may also impair the transplacental transfer of some antibodies. Two hundred and thirteen Gambian mother-baby pairs were studied to determine the influence of placental malaria infection and maternal hypergammaglobulinaemia on transplacental transfer of measles and tetanus antibodies in Gambian population. Placental blood and tissue were collected for placental malaria diagnosis. Cord and maternal sera were tested for total IgG concentration by laser nephelometry and for IgG antibody to tetanus toxoid and measles by ELISA. The prevalence of placental malaria infection was 51.1%. Mothers whose placentae were parasitized had a significantly higher mean total serum IgG (22.0 g/L vs 11.3 g/L, p < 0.001) and measles antibody level (4.02 IU/mL vs 1.21 IU/mL, p < 0.01), but not tetanus antibody, than mothers with non-parasitized placentae. Results of multiple regression analysis showed that placental malaria infection and maternal hypergammaglobulinaemia were associated with the reduction of 72% (95% CI 67.84) and 86% (95% CI 76.91) in transplacental transfer of measles antibody respectively but did not influence the transfer of tetanus antibody. It is concluded that the combined influence of placental malaria infection and maternal hypergammaglobulinaemia is significantly associated with the transfer of impaired measles antibody in this population.