Yali Hu

Gaps in the prevention of perinatal transmission of hepatitis B virus between recommendations and routine practices in a highly endemic region: a provincial population-based study in China.

BackgroundHepatitis B virus (HBV) infection is endemic in China; perinatal transmission is the main source of chronic HBV infection. Simultaneous administration of hepatitis B immune globulin (HBIG) and hepatitis B vaccine is highly effective to prevent perinatal transmission of HBV; however, the effectiveness also depends on full adherence to the recommended protocols in daily practice. In the present investigation, we aimed to identify gaps in immunoprophylaxis of perinatal transmission of HBV between recommendations and routine practices in Jiangsu Province, China.MethodsTotally 626 children from 6 cities and 8 rural areas across Jiangsu Province, China, born from February 2003 to December 2004, were enrolled; 298 were born to mothers with positive hepatitis B surface antigen (HBsAg) and 328 were born to HBsAg-negative mothers. Immunoprophylactic measures against hepatitis B were retrospectively reviewed for about half of the children by checking medical records or vaccination cards and the vaccine status was validated for most of children.ResultsOf 298 children born to HBV carrier mothers, 11 (3.7%) were HBsAg positive, while none of 328 children born to non-carrier mothers was HBsAg positive (P < 0.01). The rates of anti-HBs ≥ 10 mIU/ml in children of carrier and non-carrier mothers were 69.5% and 69.2% respectively (P = 0.95). The hepatitis B vaccine coverage in two groups was 100% and 99.4% respectively (P = 0.50), but 15.1% of HBV-exposed infants did not receive the timely birth dose. Prenatal HBsAg screening was performed only in 156 (52.3%) of the carrier mothers. Consequently, only 112 (37.6%) of HBV-exposed infants received HBIG after birth. Furthermore, of the 11 HBV-infected children, only one received both HBIG and hepatitis B vaccine timely, seven missed HBIG, two received delayed vaccination, and one missed HBIG and received delayed vaccination.ConclusionsThere are substantial gaps in the prevention of perinatal HBV infection between the recommendations and routine practices in China, which highlights the importance of full adherence to the recommendations to eliminate perinatal HBV infection in the endemic regions.

Influence of maternal antibody against hepatitis B surface antigen on active immune response to hepatitis B vaccine in infants

Transplacentally acquired maternal antibodies in infants may inhibit active immune responses to vaccines. In this study, we compared the immunogenicity of the recombinant hepatitis B vaccine, which was intramuscularly injected at 0, 1, and 6 months of age, in 71 infants born to mothers with positive or negative antibody against hepatitis B surface antigen (anti-HBs). Forty-one infants born to anti-HBs positive mothers were all positive at birth. At 2 months after the second injection, anti-HBs in 30 infants with negative maternal antibody was significantly higher than that in 41 infants with positive maternal anti-HBs (191.1mIU/ml vs. 96.2mIU/ml, P=0.018). At one month after the full immunization, the anti-HBs levels had no statistical difference between maternal anti-HBs negative and positive groups, but the antibody response in infants with high maternal anti-HBs (>1000mIU/ml) was significantly inhibited. Nevertheless, all infants had anti-HBs higher than the protective level. In conclusion, passively acquired maternal anti-HBs in infants may to some extent impair the antibody response to hepatitis B vaccine. The long-term efficacy of hepatitis B vaccine in infants with high titers of maternal anti-HBs remains to be further evaluated.

Transplacentally acquired maternal antibody against hepatitis B surface antigen in infants and its influence on the response to hepatitis B vaccine.

Background Passively acquired maternal antibodies in infants may inhibit active immune responses to vaccines. Whether maternal antibody against hepatitis B surface antigen (anti-HBs) in infants may influence the long-term immunogenicity of hepatitis B vaccine remains unknown. Methodology/Principal Findings Totally 338 pairs of mothers and children were enrolled. All infants were routinely vaccinated against hepatitis B based on 0-, 1- and 6-month schedule. We characterized the transplacental transfer of maternal anti-HBs, and compared anti-HBs response in children of mothers with or without anti-HBs. In a prospective observation, all 63 anti-HBs positive mothers transferred anti-HBs to their infants; 84.1% of the infants had higher anti-HBs concentrations than their mothers. One and half years after vaccination with three doses of hepatitis B vaccine, the positive rate and geometric mean concentration (GMC) of anti-HBs in 32 infants with maternal anti-HBs were comparable with those in 32 infants without maternal antibody (90.6% vs 87.5%, P = 0.688, and 74.5 vs 73.5 mIU/ml, P = 0.742, respectively). In a retrospective analysis, five and half years after vaccination with three doses vaccine, the positive rates of anti-HBs in 88 children of mothers with anti-HBs ≥1000 mIU/ml, 94 children of mothers with anti-HBs 10–999 mIU/ml, and 61 children of mothers with anti-HBs <10 mIU/ml were 72.7%, 69.2%, and 63.9% (P = 0.521), respectively; anti-HBs GMC in these three groups were 38.9, 43.9, and 31.7 mIU/ml (P = 0.726), respectively. Conclusions/Significance The data demonstrate that maternal anti-HBs in infants, even at high concentrations, does not inhibit the long-term immunogenicity of hepatitis B vaccine. Thus, current hepatitis B vaccination schedule for infants will be still effective in the future when most infants are positive for maternal anti-HBs due to the massive vaccination against hepatitis B.

Kinetics of IgG antibody to cytomegalovirus (CMV) after birth and seroprevalence of anti-CMV IgG in Chinese children

BackgroundPrevalence of cytomegalovirus (CMV) infection is 90–100% in developing countries; however, the kinetics of anti-CMV IgG in infants remains elusive.MethodsSera from 112 mother-newborn pairs and longitudinal samples from 41 infants up to 2-year old were tested for anti-CMV IgG and IgM. Additionally, samples from 837 healthy children were included.ResultsOf 112 mothers, 108 (96.4%) were anti-CMV IgG positive; their 108 newborns were also seropositive. In a 2-year follow-up among 40 infants of positive mothers, anti-CMV IgG level in 8 individuals decreased with time and became undetectable by age of 3.5–8 months, and that in 32 others decreased at 1- and 3.5-month old, and then increased. Based on the positive IgM, rising IgG levels, and low anti-CMV IgG avidity index, 76.7% of the primary infections were demonstrated to occur during 1–3.5 months of age. The overall seroprevalence of anti-CMV in 837 children was 82.4%, which was generally constant from 2 to 8 years old (χ2 = 3.150, p = 0.790).ConclusionsThe maternally acquired anti-CMV IgG in infants disappears before 8-month old. Primary CMV infection in Chinese children mostly occurs during 1–3.5 months of age. Whether the relatively lower seroprevalence of anti-CMV in Chinese children found in this survey may reflect the positive rate in child-bearing age women in the future remains to be further studied.

Low titers of measles antibody in mothers whose infants suffered from measles before eligible age for measles vaccination

BackgroundResurgence or outbreak of measles recently occurred in both developed and developing countries despite long-standing widespread use of measles vaccine. Measles incidence in China has increased since 2002, particularly in infants and in persons ≥ 15 years of age. It is speculated that infants may acquire fewer measles IgG from their mothers, resulting in the reduced duration of protection during their early months of life. This study aimed to clarify the reason of increased susceptibility to measles in young infants in China. Measles IgG in 24 measles infants ≤ 9 months of age and their vaccinated mothers was quantitatively measured. The mean measles neutralizing titer in the vaccinated mothers and in 13 age-match women with the histories of clinical measles were compared.ResultsAll the mothers were confirmed to be vaccinated successfully by the presence of measles IgG. Six vaccinated mothers were positive for measles IgM and had high concentrations of measles IgG and the neutralizing antibody, indicating underwent natural boosting. The mean measles neutralizing titer in 18 vaccinated mothers without natural boosting were significantly lower than that in 13 age-match women with the histories of clinical measles (1:37 vs 1:182, P < 0.05).ConclusionsOur results suggest that infants born to mothers who acquired immunity to measles by vaccination may get a relatively small amount of measles antibody, resulting in loss of the immunity to measles before the vaccination age. Measures to improve the immunity in young infants not eligible for measles vaccination would be critical to interrupt the measles transmission in China.

Association of polymorphisms of cytokine and TLR-2 genes with long-term immunity to hepatitis B in children vaccinated early in life

Hepatitis B vaccine is effective in preventing hepatitis B virus (HBV) infection. However, 5-10% of vaccinees fail to produce sufficient antibody against hepatitis B surface antigen (anti-HBs). In this study, we investigated the association of genetic polymorphisms with long-term response to hepatitis B vaccine in 301 children who received the vaccine 5-7 years ago. Of them, 86 (28.6%) had anti-HBs <10 mIU/ml (group A) and 215 (71.4%) had anti-HBs ≥10 mIU/ml (group B). While the frequencies of T allele and TT genotype in single nucleotide polymorphisms (SNP) rs2243250 and rs2070874 of interleukin (IL)-4 in group A were higher than those in group B (all P<0.05 and q<0.2), the frequency of C allele in SNP rs2243250, rs2070874 and rs2227284 of IL-4 in group B was higher than that in group A (all P<0.05 and q<0.2). None of 11 other SNP in IL-2, IL-10, IL-1β, IL-13, IL-12B, tumor necrosis factor-α, and toll-like receptor-2 genes was found to associate with anti-HBs response. SNP rs2070874 was associated with humoral response to hepatitis B vaccine after analyzed by multivariable logistic regression analysis (P=0.015). The haplotype TT defined by SNP rs2243250 and rs2070874 in IL-4 was associated with the poor humoral response (adjusted P=0.037). Our findings demonstrate that IL-4 gene polymorphisms may affect the long-term immune response to hepatitis B vaccine.

Survey of human papillomavirus types and their vertical transmission in pregnant women.

BackgroundThe prevalence, genotypes, and vertical transmission characteristics of human papillomavirus (HPV) among pregnant women from Nanjing, China was investigated.MethodsCervical cells were collected from healthy pregnant women (n = 3139; stage of gestation, 24.6 ± 2.1 weeks) for cytological evaluation and determination of HPV infection status. Exfoliated oral and genital cells were collected from neonates (<1-day-old, n = 233) whose mothers were positive for HPV DNA. We used HPV Gene Chip technology with 23 HPV genotype probes to conduct our analysis.ResultsOverall prevalence of HPV DNA among pregnant women was 13.4% (422/3139). The most frequently detected HPV genotypes were HPV-16 (29.6%, 125/422), -18 (14.7%, 62/422), and -58 (14.2%, 60/422). The rate of concordance for HPV DNA in maternal-neonatal pairs was 23.6% (55/233), with HPV type-specific concordance occurring in 26 cases. A higher prevalence of HPV DNA was apparent in female neonates compared with males (17.7 vs. 11.6%).ConclusionsThe prevalence of cervical HPV DNA in pregnant women from Nanjing was low, with vertical transmission rates slightly higher. From our findings, we concluded that there was efficient vertical transmission of three HPV genotypes, with HPV-16 the most prevalent type in pregnant women and newborn babies.

Second trimester amniotic fluid cytokine concentrations, Ureaplasma sp. colonisation status and sexual activity as predictors of preterm birth in Chinese and Australian women

BackgroundThis study tested if second trimester amniotic fluid cytokine levels, Ureaplasma sp. colonisation and sexual activity predict preterm birth and explain the differential preterm birth rates in Chinese compared to Australian women.MethodsAmniotic fluid was collected by amniocentesis (Chinese 480, Australian 492). Cytokines were measured by multiplex assay and Ureaplasma sp. DNA was detected by PCR analysis. Lifestyle factors, including history of smoking and sexual activity during pregnancy, were obtained through completion of questionnaires upon recruitment to the study.ResultsInflammatory cytokine concentrations were poorly predictive of preterm birth. Ureaplasma sp. was detected in two of the Chinese pregnancies and none from Australia. Sexual activity was less frequent in Chinese, and was not associated with preterm birth or amniotic fluid findings in either population.DiscussionSecond trimester amniocentesis for measurement of inflammatory markers and Ureaplasma sp. DNA was not indicative of risk of preterm birth, at least in these populations. The lower rate of preterm birth in China was not explained by differences in amniotic fluid inflammatory markers, Ureaplasma sp. colonisation, or sexual activity.