The Cytomegalovirus Infection In Pregnant Women And Newborns In High Seroprevalent Regions:a Prospective Cohort Study

Background:Congenital cytomegalovirus(CMV)infection is one of the leading causes of infant disabilities,including sensorineural hearing loss(SNHL)and developmental delay.The primary infection in seronegative pregnant women or nonprimary infection(including reinfection and reactivation)in seropositive pregnant women(with a history of CMV infection)may cause congenital CMV infection in newborns.In China,it’s reported the seroprevalence was extremely high and congenital CMV prevalence was also relatively high.However,in highly seroprevalent regions including China,the congenital CMV infection is largely unrecognized and underemphasized;the method to identify population with high risk,optimal screening strategy and the protective effect of maternal pre-existing immunity remain unkown.Objectives:This research aims at understanding the epidemiology of CMV infection in pregnant women and newborns in China,and to further provide the scientific evidence relevant to several important aspects in congenital CMV infection control and management in highly seroprevalent regions.Methods:A perspective cohort study and a nested case-control study were designed.From Jul 2015 to Jun 2018,the pregnant women in the early pregnancy were consecutively enrolled in Xinmi Maternal and Child Health Hospital(MCHH),Zhongmu MCHH and Jiaxian MCHH,and followed-up in the middle and late pregnancy,with blood and urine collection at each time for detection of immunological indicators,virological indicators and metabolomics.The newborns were further followed up and collected with saliva and urine for screening of congenital CMV infection by CMV-DNA PCR detection.The newborns with positive result in the screening were subsequently collected saliva and urine samples for confirmatory testing within 21 days of age.In the cohort study,by analyzing maternal CMV-IgG level during pregnancy and CMV-DNA results of newborns,we analyzed the epidemiology of CMV infection in pregnant women and newborns,explored the optimal detection strategy for congenital CMV infection screening,and the dynamic of antibody during pregnancy and its relationship with outcome of congenital CMV infection.Based on the cohort,the congenital CMV infection newborns and matched uninfected newborn were included in a nested case-control study to explore the differential indicators in the two groups,including the potential indicators as IgM,IgG avidity,CMV-DNA in urine and blood,metabolites.Results:A total of 6729 pregnant women were enrolled in the early pregnancy(around 13.9 gestational weeks(gw)),among which 5537 were successefully followed up in the middle and late pregnancy(around 25.5 gw and 38.0 gw).In 6350 newborns who were performed congenital CMV infection screening soon after delivery(at around 1 days of age),287 were tested positive,and among them 254 were completed the collection of subsequent samples and confirmatory testing.Finally,49 newborns were confirmed as congenital CMV infection,and 35 newborns were deemed as highly suspected congenital CMV infection,and 33 were deemed as suspected congenital CMV infection.In the first part,the epidemiology of CMV infection in pregnant women and newborns were attained.The CMV seroprevalence in pregnant women was 98.11%(6602/6729,95%CI:97.76%-98.41%),and congenital CMV prevalence was 1.27%(80.51/6350,95%CI:1.02%-1.57%).Newborns from pregnant women under 25 years old or from twin pregnancies had a higher prevalence of congenital CMV infection,with OR value of 1.84 and 3.99 respectively.The majority(98.41%)of congenital CMV newborns were from pregnant women who were seropositive in early gestation in China.The prevalence of congenital CMV infection in newborns from seropositive and seronegative pregnant women was similar(1.27%vs 1.05%,P=0.32).In the second part,the optimal detection strategy for congenital CMV infection screening was explored.In the screening test,the CMV DNA positivity rate remained similar from day 0 to day 5,increased slowly from day 6 to day 13,and became high in newborns beyond 13 days of birth.In the confirmatory testing,the positive rates increased significantly beyond day 21.For the 49 newborns with congenital CMV infection,the proportion of agreement between saliva and urine testing was poor.Upon evaluating alternative screening strategies,using saliva and urine screening with saliva and urine confirmation as the reference strategy,saliva screening with saliva and urine confirmation showed good diagnostic accuracy and feasibility,with sensitivity,specificity,positive predictive value(PPV)and negative predictive value(NPV)of 85.7%,100.0%,100.0%and 99.9%,respectively.In the third part,the protective effect of pre-existing maternal immunity against congenital congenital CMV was quantitatively measured.The geometric mean concentration(GMC)of CMV-IgG at an early gestational age in the women who delivered congenital CMV-positive newborns(i.e.,the transmitters)was 8.54 IU/mL;this was significantly lower than the GMC in the non-transmitters(11.01 IU/mL;P=0.04).In early gestation,the risk of congenital CMV infection decreased as maternal IgG antibody levels increased(P=0.020);however,the same was not true in middle or late gestation(P>0.05).The rate of fourfold rise was 5.11 times higher in transmitters comparing with nontransmitters.Using receiver operating characteristic analysis,a CMV-IgG concentration of 12.83 IU/mL was established as the optimal diagnostic threshold.Compared to lower levels of CMV-IgG(<12.83 IU/mL)in seropositive pregnant women,higher maternal CMV-IgG levels(≥12.83 IU/mL)were associated with a 50%reduction in congenital CMV infection risk in infants(relative risk=0.50;95%confidence interval:0.27-0.93;P=0.028).In the fourth part,48 newborns with confirmed congenital CMV infection,35 newborns with highly suspected congenital CMV infection and mathed 249 uninfected newborns were included,and the relationship of potential immunological,virological and metabolomics indicators with congenital CMV infection was analyzed.In seropositive pregnant women,the IgM and IgG avidity and CMV shedding in urine wasn’t associated with outcome of congenital CMV infection.Pregnant women with CMV viremia in the early,middle and late pregnancy indicating a higher risk of vertical transmission,with the OR values of 5.0,5.9 and 8.9 respectively,and the percentages of population attributable risk were 32.6%,33.3%and 45.5%respectively.However,the sensitivity(0.21-0.25)and PPV(0.05-0.07)are low if applying blood testing of CMV-DNA in screening of congenital CMV infection.47 newborns with confirmed congenital CMV infection and mathed 47 uninfected newborns were included in the analysis of the association between potential metabolomics indicators and congenital CMV infection,and a total of 15 differential metabolites were identified in the nontargeted metabolomics analysis,which requires further validation.Based on the data existing,additional analysis were conducted,as follow:(1)in the analysis of congenital CMV infection in twin pregnancy,it was showed that women with low CMV antibody level and twin pregnancy was facing 9.38 times higher risk of vertical transmission,which should be emphasized in congenital CMV infection screening;(2)In the analysis of miscarriage cases,indicators relavant to CMV infection in pregnant women weren’t associated with outcome of miscarriage;(3)The agreement between two consensus in congenital CMV infection diagnosis was low(kappa=0.39).Conclusions:The prevalence of congenital CMV infection in China is high,and the majority of congenital CMV infection was from seropositive pregnant women,which should be target population in congenital CMV infection control.In settings with limited medical resources,saliva screening(within 13(ideally 5)days of age)with saliva and urine confirmation(within 21(ideally 13)days of age)might be an alternative strategy for screening congenital CMV infections.In seropositive women,high pre-existing maternal immunity was protective against congenital cytomegalovirus infection.In seropositive pregnant women,CMV IgM and IgG avidity were unrelated with congenital CMV infection.Although CMV-DNA in blood or IgG fourfold rise indicated a higher risk of congenital CMV infection,the diagnosis accuracy was low.