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Roma Chilengi - One of the best experts on this subject based on the ideXlab platform.

  • contribution of Maternal Immunity to decreased rotavirus vaccine performance in low and middle income countries
    Clinical and Vaccine Immunology, 2017
    Co-Authors: Katayi Mwila, Roma Chilengi, Michelo Simuyandi, Sallie R Permar, Sylvia Beckerdreps
    Abstract:

    The role of Maternal Immunity, received by infants either transplacentally or orally from breast milk, in rotavirus vaccine (RV) performance is evaluated here. Breastfeeding withholding has no effect on vaccine responses, but higher levels of transplacental rotavirus-specific IgG antibody contribute to reduced vaccine seroconversion. The gaps in knowledge on the factors associated with low RV efficacy in low- and middle-income countries (LMIC) remain, and further research is needed to shed more light on these issues.

  • association of Maternal Immunity with rotavirus vaccine immunogenicity in zambian infants
    PLOS ONE, 2016
    Co-Authors: Roma Chilengi, Michelo Simuyandi, Lauren Beach, Katayi Mwila, Sylvia Beckerdreps, Devy M Emperador, Daniel E Velasquez, Samuel Bosomprah, Baoming Jiang
    Abstract:

    Introduction Live attenuated oral vaccines against rotavirus (RV) have been shown to be less efficacious in children from developing countries. Reasons for this disparity are not fully understood. We assessed the role of Maternal factors including breast milk RV-specific IgA, transplacentally acquired infant serum RV-specific IgG and Maternal HIV status in seroconversion among Zambian infants routinely immunized with Rotarix™ (RV1). Methods 420 mother-child pairs were recruited at infant age 6–12 weeks in Lusaka. Clinical information and samples were collected at baseline and at one month following the second dose of RV1. Determination of breast milk RV-specific IgA and serum RV-specific IgA and IgG was done using standardized ELISA. Seroconversion was defined as a ≥ 4 fold rise in serum IgA titre from baseline to one-month post RV1 dose 2, while seropositivity of IgA was defined as serum titre ≥ 40 and antibody variables were modelled on log-base 2. Logistic regression was used to identify predictors of the odds of seroconversion. Results Baseline infant seropositivity was 25.5% (91/357). The seroconversion frequency was 60.2% (130/216). Infants who were IgA seropositive at baseline were less likely to seroconvert compared to their seronegative counterparts (P = 0.04). There was no evidence of an association between Maternal HIV status and seroconversion (P = 0.25). Higher titres of breast milk rotavirus-specific IgA were associated with a lower frequency of seroconverson (Nonparametric test for trend Z = -2.84; P<0.01): a two-fold increase in breast milk RV-specific IgA titres was associated with a 22% lower odds of seroconversion (OR = 0.80; 95% CI = 0.68–0.94; P = 0.01). There was seasonal variation in baseline breast milk rotavirus-specific IgA titres, with significantly higher GMTs during the cold dry months (P = 0.01). Conclusion Low immunogenicity of RV1 vaccine could be explained in part by exposure to high antibody titres in breast milk and early exposure to wild-type rotavirus infections. Potential interference of anti-RV specific IgA in breast milk and pre-vaccination serum RV specific-IgA and IgG titres with RV1 seroconversion and effectiveness requires further research.

  • association of Maternal Immunity with rotavirus vaccine immunogenicity in zambian infants
    PLOS ONE, 2016
    Co-Authors: Roma Chilengi, Michelo Simuyandi, Katayi Mwila, Sylvia Beckerdreps, Devy M Emperador, Daniel E Velasquez, Samuel Bosomprah, Lauren Brittany Beach, Baoming Jiang
    Abstract:

    Introduction Live attenuated oral vaccines against rotavirus (RV) have been shown to be less efficacious in children from developing countries. Reasons for this disparity are not fully understood. We assessed the role of Maternal factors including breast milk RV-specific IgA, transplacentally acquired infant serum RV-specific IgG and Maternal HIV status in seroconversion among Zambian infants routinely immunized with Rotarix™ (RV1). Methods 420 mother-child pairs were recruited at infant age 6–12 weeks in Lusaka. Clinical information and samples were collected at baseline and at one month following the second dose of RV1. Determination of breast milk RV-specific IgA and serum RV-specific IgA and IgG was done using standardized ELISA. Seroconversion was defined as a ≥ 4 fold rise in serum IgA titre from baseline to one-month post RV1 dose 2, while seropositivity of IgA was defined as serum titre ≥ 40 and antibody variables were modelled on log-base 2. Logistic regression was used to identify predictors of the odds of seroconversion. Results Baseline infant seropositivity was 25.5% (91/357). The seroconversion frequency was 60.2% (130/216). Infants who were IgA seropositive at baseline were less likely to seroconvert compared to their seronegative counterparts (P = 0.04). There was no evidence of an association between Maternal HIV status and seroconversion (P = 0.25). Higher titres of breast milk rotavirus-specific IgA were associated with a lower frequency of seroconverson (Nonparametric test for trend Z = -2.84; P<0.01): a two-fold increase in breast milk RV-specific IgA titres was associated with a 22% lower odds of seroconversion (OR = 0.80; 95% CI = 0.68–0.94; P = 0.01). There was seasonal variation in baseline breast milk rotavirus-specific IgA titres, with significantly higher GMTs during the cold dry months (P = 0.01). Conclusion Low immunogenicity of RV1 vaccine could be explained in part by exposure to high antibody titres in breast milk and early exposure to wild-type rotavirus infections. Potential interference of anti-RV specific IgA in breast milk and pre-vaccination serum RV specific-IgA and IgG titres with RV1 seroconversion and effectiveness requires further research.

Baoming Jiang - One of the best experts on this subject based on the ideXlab platform.

  • association of Maternal Immunity with rotavirus vaccine immunogenicity in zambian infants
    PLOS ONE, 2016
    Co-Authors: Roma Chilengi, Michelo Simuyandi, Lauren Beach, Katayi Mwila, Sylvia Beckerdreps, Devy M Emperador, Daniel E Velasquez, Samuel Bosomprah, Baoming Jiang
    Abstract:

    Introduction Live attenuated oral vaccines against rotavirus (RV) have been shown to be less efficacious in children from developing countries. Reasons for this disparity are not fully understood. We assessed the role of Maternal factors including breast milk RV-specific IgA, transplacentally acquired infant serum RV-specific IgG and Maternal HIV status in seroconversion among Zambian infants routinely immunized with Rotarix™ (RV1). Methods 420 mother-child pairs were recruited at infant age 6–12 weeks in Lusaka. Clinical information and samples were collected at baseline and at one month following the second dose of RV1. Determination of breast milk RV-specific IgA and serum RV-specific IgA and IgG was done using standardized ELISA. Seroconversion was defined as a ≥ 4 fold rise in serum IgA titre from baseline to one-month post RV1 dose 2, while seropositivity of IgA was defined as serum titre ≥ 40 and antibody variables were modelled on log-base 2. Logistic regression was used to identify predictors of the odds of seroconversion. Results Baseline infant seropositivity was 25.5% (91/357). The seroconversion frequency was 60.2% (130/216). Infants who were IgA seropositive at baseline were less likely to seroconvert compared to their seronegative counterparts (P = 0.04). There was no evidence of an association between Maternal HIV status and seroconversion (P = 0.25). Higher titres of breast milk rotavirus-specific IgA were associated with a lower frequency of seroconverson (Nonparametric test for trend Z = -2.84; P<0.01): a two-fold increase in breast milk RV-specific IgA titres was associated with a 22% lower odds of seroconversion (OR = 0.80; 95% CI = 0.68–0.94; P = 0.01). There was seasonal variation in baseline breast milk rotavirus-specific IgA titres, with significantly higher GMTs during the cold dry months (P = 0.01). Conclusion Low immunogenicity of RV1 vaccine could be explained in part by exposure to high antibody titres in breast milk and early exposure to wild-type rotavirus infections. Potential interference of anti-RV specific IgA in breast milk and pre-vaccination serum RV specific-IgA and IgG titres with RV1 seroconversion and effectiveness requires further research.

  • association of Maternal Immunity with rotavirus vaccine immunogenicity in zambian infants
    PLOS ONE, 2016
    Co-Authors: Roma Chilengi, Michelo Simuyandi, Katayi Mwila, Sylvia Beckerdreps, Devy M Emperador, Daniel E Velasquez, Samuel Bosomprah, Lauren Brittany Beach, Baoming Jiang
    Abstract:

    Introduction Live attenuated oral vaccines against rotavirus (RV) have been shown to be less efficacious in children from developing countries. Reasons for this disparity are not fully understood. We assessed the role of Maternal factors including breast milk RV-specific IgA, transplacentally acquired infant serum RV-specific IgG and Maternal HIV status in seroconversion among Zambian infants routinely immunized with Rotarix™ (RV1). Methods 420 mother-child pairs were recruited at infant age 6–12 weeks in Lusaka. Clinical information and samples were collected at baseline and at one month following the second dose of RV1. Determination of breast milk RV-specific IgA and serum RV-specific IgA and IgG was done using standardized ELISA. Seroconversion was defined as a ≥ 4 fold rise in serum IgA titre from baseline to one-month post RV1 dose 2, while seropositivity of IgA was defined as serum titre ≥ 40 and antibody variables were modelled on log-base 2. Logistic regression was used to identify predictors of the odds of seroconversion. Results Baseline infant seropositivity was 25.5% (91/357). The seroconversion frequency was 60.2% (130/216). Infants who were IgA seropositive at baseline were less likely to seroconvert compared to their seronegative counterparts (P = 0.04). There was no evidence of an association between Maternal HIV status and seroconversion (P = 0.25). Higher titres of breast milk rotavirus-specific IgA were associated with a lower frequency of seroconverson (Nonparametric test for trend Z = -2.84; P<0.01): a two-fold increase in breast milk RV-specific IgA titres was associated with a 22% lower odds of seroconversion (OR = 0.80; 95% CI = 0.68–0.94; P = 0.01). There was seasonal variation in baseline breast milk rotavirus-specific IgA titres, with significantly higher GMTs during the cold dry months (P = 0.01). Conclusion Low immunogenicity of RV1 vaccine could be explained in part by exposure to high antibody titres in breast milk and early exposure to wild-type rotavirus infections. Potential interference of anti-RV specific IgA in breast milk and pre-vaccination serum RV specific-IgA and IgG titres with RV1 seroconversion and effectiveness requires further research.

Sallie R Permar - One of the best experts on this subject based on the ideXlab platform.

  • impact of Maternal Immunity on congenital cytomegalovirus birth prevalence and infant outcomes a systematic review
    Vaccine, 2019
    Co-Authors: Tiziana Coppola, Sallie R Permar, Jesse F Mangold, Sarah Cantrell
    Abstract:

    Congenital cytomegalovirus (cCMV) is the leading non-genetic cause of sensorineural hearing loss (SNHL), and efforts are geared towards prevention through vaccine development. Transmission rates following primary Maternal infection occur at rates of 30–40%, however reported placental rates upon non-primary Maternal infection is reported to be less than 80%) areas or in developing regions that examined a cohort of at least 50 infants for congenital CMV acquisition. We identified 19 articles that met criteria and were further categorized based on pre-conception serology, Maternal seroprevalence, or previously known seroprevalence. Birth prevalence rates ranged from 0.4% to 6% (median 1.1%), with the studies reporting on clinical outcome (16/19 studies) noting the majority of infected infants as asymptomatic. We also utilized a recent study that differentiated primary Maternal infections from chronic infections in a highly seropositive population to calculate a placental transmission rate in women with pre-existing Immunity compared to that of no pre-existing Immunity. This work confirms a low cCMV birth prevalence in highly seropositive populations, indicates via a calculated placental transmission rate that the CMV placental transmission rate is lower in non-primary infection than that of primary infection, and reveals gaps in data for further research aiming to identify targets for vaccine development.

  • advancing our understanding of protective Maternal Immunity as a guide for development of vaccines to reduce congenital cytomegalovirus infections
    Journal of Virology, 2018
    Co-Authors: Sallie R Permar, Mark R Schleiss, Stanley A Plotkin
    Abstract:

    Human cytomegalovirus (HCMV) is the most common congenitally transmitted pathogen worldwide, impacting an estimated 1 million newborns annually. Congenital HCMV (cCMV) infection is a major global contributor to long-term neurologic deficits, including deafness, microcephaly, and neurodevelopmental delay, as well as to fetal loss and occasional infant mortality. Accordingly, design of a Maternal vaccine to prevent cCMV continues to be a top public health priority. Nevertheless, we remain without a licensed vaccine. Maternal Immunity provides partial protection, as the risk of vertical HCMV transmission from chronically infected mothers is reduced compared to settings in which the mother is newly infected during pregnancy. Therefore, an understanding of the Maternal immune correlates of protection against cCMV is critical to informing design of an efficacious Maternal vaccine. Although vaccine development is being assiduously pursued by a large number of pharmaceutical manufacturers, biotechnology organizations, and academic researchers, some pessimism has been expressed regarding the issue of whether a vaccine to protect against cCMV is possible. This pessimism is based on observations that natural Immunity is not completely protective against Maternal reinfection and congenital transmission. However, we assert that optimism regarding vaccine development is indeed justified, on the basis of accruing evidence of immune correlates of protection-readily achievable by vaccination-that are associated with reduced transmission of HCMV to the fetus in seronegative women. In light of the substantial burden on society conferred by cCMV infection, even a modest reduction in the occurrence of this fetal disease is an important public health goal and justifies aggressive clinical evaluation of vaccines currently in the pipeline.

  • contribution of Maternal Immunity to decreased rotavirus vaccine performance in low and middle income countries
    Clinical and Vaccine Immunology, 2017
    Co-Authors: Katayi Mwila, Roma Chilengi, Michelo Simuyandi, Sallie R Permar, Sylvia Beckerdreps
    Abstract:

    The role of Maternal Immunity, received by infants either transplacentally or orally from breast milk, in rotavirus vaccine (RV) performance is evaluated here. Breastfeeding withholding has no effect on vaccine responses, but higher levels of transplacental rotavirus-specific IgG antibody contribute to reduced vaccine seroconversion. The gaps in knowledge on the factors associated with low RV efficacy in low- and middle-income countries (LMIC) remain, and further research is needed to shed more light on these issues.

  • Maternal immune correlates of protection against placental transmission of cytomegalovirus.
    Placenta, 2017
    Co-Authors: Hannah L. Itell, Cody S. Nelson, David R. Martinez, Sallie R Permar
    Abstract:

    Human cytomegalovirus (HCMV) is the most common congenitally transmitted pathogen worldwide, impacting an estimated 1 million newborns annually. In a subset of infected infants, congenital HCMV causes severe, long-lasting sequelae, including deafness, microcephaly, neurodevelopmental delay, and even death. Accordingly, a Maternal vaccine to prevent congenital HCMV infection continues to be a top public health priority. Nevertheless, all vaccines tested to date have failed to meet clinical trial endpoints. Maternal Immunity provides partial protection against congenital HCMV transmission, as vertical transmission from seropositive mothers is relatively rare. Therefore, an understanding of the Maternal immune correlates of protection against HCMV congenital infection will be critical to inform design of an efficacious Maternal vaccine. This review summarizes our understanding of the innate and adaptive immune correlates of protection against congenital transmission of HCMV, and discusses the advantages and applications of a novel nonhuman primate model of congenital CMV transmission to aid in rational vaccine design and evaluation.

Sylvia Beckerdreps - One of the best experts on this subject based on the ideXlab platform.

  • contribution of Maternal Immunity to decreased rotavirus vaccine performance in low and middle income countries
    Clinical and Vaccine Immunology, 2017
    Co-Authors: Katayi Mwila, Roma Chilengi, Michelo Simuyandi, Sallie R Permar, Sylvia Beckerdreps
    Abstract:

    The role of Maternal Immunity, received by infants either transplacentally or orally from breast milk, in rotavirus vaccine (RV) performance is evaluated here. Breastfeeding withholding has no effect on vaccine responses, but higher levels of transplacental rotavirus-specific IgG antibody contribute to reduced vaccine seroconversion. The gaps in knowledge on the factors associated with low RV efficacy in low- and middle-income countries (LMIC) remain, and further research is needed to shed more light on these issues.

  • association of Maternal Immunity with rotavirus vaccine immunogenicity in zambian infants
    PLOS ONE, 2016
    Co-Authors: Roma Chilengi, Michelo Simuyandi, Lauren Beach, Katayi Mwila, Sylvia Beckerdreps, Devy M Emperador, Daniel E Velasquez, Samuel Bosomprah, Baoming Jiang
    Abstract:

    Introduction Live attenuated oral vaccines against rotavirus (RV) have been shown to be less efficacious in children from developing countries. Reasons for this disparity are not fully understood. We assessed the role of Maternal factors including breast milk RV-specific IgA, transplacentally acquired infant serum RV-specific IgG and Maternal HIV status in seroconversion among Zambian infants routinely immunized with Rotarix™ (RV1). Methods 420 mother-child pairs were recruited at infant age 6–12 weeks in Lusaka. Clinical information and samples were collected at baseline and at one month following the second dose of RV1. Determination of breast milk RV-specific IgA and serum RV-specific IgA and IgG was done using standardized ELISA. Seroconversion was defined as a ≥ 4 fold rise in serum IgA titre from baseline to one-month post RV1 dose 2, while seropositivity of IgA was defined as serum titre ≥ 40 and antibody variables were modelled on log-base 2. Logistic regression was used to identify predictors of the odds of seroconversion. Results Baseline infant seropositivity was 25.5% (91/357). The seroconversion frequency was 60.2% (130/216). Infants who were IgA seropositive at baseline were less likely to seroconvert compared to their seronegative counterparts (P = 0.04). There was no evidence of an association between Maternal HIV status and seroconversion (P = 0.25). Higher titres of breast milk rotavirus-specific IgA were associated with a lower frequency of seroconverson (Nonparametric test for trend Z = -2.84; P<0.01): a two-fold increase in breast milk RV-specific IgA titres was associated with a 22% lower odds of seroconversion (OR = 0.80; 95% CI = 0.68–0.94; P = 0.01). There was seasonal variation in baseline breast milk rotavirus-specific IgA titres, with significantly higher GMTs during the cold dry months (P = 0.01). Conclusion Low immunogenicity of RV1 vaccine could be explained in part by exposure to high antibody titres in breast milk and early exposure to wild-type rotavirus infections. Potential interference of anti-RV specific IgA in breast milk and pre-vaccination serum RV specific-IgA and IgG titres with RV1 seroconversion and effectiveness requires further research.

  • association of Maternal Immunity with rotavirus vaccine immunogenicity in zambian infants
    PLOS ONE, 2016
    Co-Authors: Roma Chilengi, Michelo Simuyandi, Katayi Mwila, Sylvia Beckerdreps, Devy M Emperador, Daniel E Velasquez, Samuel Bosomprah, Lauren Brittany Beach, Baoming Jiang
    Abstract:

    Introduction Live attenuated oral vaccines against rotavirus (RV) have been shown to be less efficacious in children from developing countries. Reasons for this disparity are not fully understood. We assessed the role of Maternal factors including breast milk RV-specific IgA, transplacentally acquired infant serum RV-specific IgG and Maternal HIV status in seroconversion among Zambian infants routinely immunized with Rotarix™ (RV1). Methods 420 mother-child pairs were recruited at infant age 6–12 weeks in Lusaka. Clinical information and samples were collected at baseline and at one month following the second dose of RV1. Determination of breast milk RV-specific IgA and serum RV-specific IgA and IgG was done using standardized ELISA. Seroconversion was defined as a ≥ 4 fold rise in serum IgA titre from baseline to one-month post RV1 dose 2, while seropositivity of IgA was defined as serum titre ≥ 40 and antibody variables were modelled on log-base 2. Logistic regression was used to identify predictors of the odds of seroconversion. Results Baseline infant seropositivity was 25.5% (91/357). The seroconversion frequency was 60.2% (130/216). Infants who were IgA seropositive at baseline were less likely to seroconvert compared to their seronegative counterparts (P = 0.04). There was no evidence of an association between Maternal HIV status and seroconversion (P = 0.25). Higher titres of breast milk rotavirus-specific IgA were associated with a lower frequency of seroconverson (Nonparametric test for trend Z = -2.84; P<0.01): a two-fold increase in breast milk RV-specific IgA titres was associated with a 22% lower odds of seroconversion (OR = 0.80; 95% CI = 0.68–0.94; P = 0.01). There was seasonal variation in baseline breast milk rotavirus-specific IgA titres, with significantly higher GMTs during the cold dry months (P = 0.01). Conclusion Low immunogenicity of RV1 vaccine could be explained in part by exposure to high antibody titres in breast milk and early exposure to wild-type rotavirus infections. Potential interference of anti-RV specific IgA in breast milk and pre-vaccination serum RV specific-IgA and IgG titres with RV1 seroconversion and effectiveness requires further research.

Tjeerd G. Kimman - One of the best experts on this subject based on the ideXlab platform.

  • The influence of Maternal Immunity on the development of the in vitro lymphocyte proliferation response against pseudorabies virus in pigs
    Research in veterinary science, 1998
    Co-Authors: Annemarie Bouma, M.d.m. De Jong, Tjeerd G. Kimman
    Abstract:

    Abstract In this study, the influence of Maternal Immunity against pseudorabies virus (PRv) on the development of a PRV-specific T-cell response in pigs was investigated. Pigs with or without Maternal Immunity were challenged by inoculation with wild-type PRv, or were vaccinated with 783 and subsequently inoculated. Peripheral blood lymphocytes, collected after vaccination and/or inoculation, were used for PRV-induced lymphocyte proliferation assays in vitro as a measure of a PRv-specific T-cell response. In unvaccinated pigs, the presence of Maternal Immunity did not inhibit the development of a T-cell response after inoculation with PRv. In contrast, Maternal Immunity did inhibit the development of a PRV-induced response after intramuscular vaccination. Moreover, vaccinated pigs without Maternal Immunity shed virus for a shorter period after inoculation than vaccinated pigs with Maternal Immunity. The greater T-cell response induced by the vaccine might have contributed to the more rapid clearance of PRV in these pigs.

  • The influence of Maternal Immunity on the transmission of pseudorabies virus and on the effectiveness of vaccination.
    Vaccine, 1997
    Co-Authors: Annemarie Bouma, M.c.m. De Jong, Tjeerd G. Kimman
    Abstract:

    The purpose of this study was to investigate whether Maternal Immunity could prevent transmission of pseudorabies virus (PRV) among pigs, and whether it reduced the effectiveness of a single or double vaccination with regard to the transmission of PRV. In five experiments, the transmission of PRV, expressed as the reproduction ratio R, was compared in groups of pigs with Maternal Immunity and in groups of pigs without Maternal Immunity. Transmission of PRV among unvaccinated pigs with Maternal Immunity (R = 0.2) was significantly lower than among pigs without Maternal Immunity (R = 6.3). Furthermore, Maternal Immunity in young pigs prevented transmission of PRV, as R was significantly below one. In once-vaccinated groups, PRV spread extensively among pigs with Maternal Immunity (R = 23), but did not spread extensively among pigs without Maternal Immunity (R = 0.6). In twice-vaccinated groups, transmission of PRV among pigs with Maternal Immunity (R = 0.6) did not differ significantly from the transmission of PRV among pigs without Maternal Immunity (R = 0.3). Thus, a single vaccination of pigs with PRV strain 783 at 10 weeks of age, when they still possessed Maternal Immunity, seemed not sufficient to prevent transmission of PRV. Virus transmission could be reduced, however, if Maternally immune pigs were vaccinated twice at 10 and 14 weeks of age.