Transient Decrease in Incidence Rate of Maternal Primary Cytomegalovirus Infection during the COVID-19 Pandemic in Japan.

This study evaluated the impact of the coronavirus disease 2019 (COVID-19) pandemic on the occurrence of maternal primary cytomegalovirus (CMV) infection in Japan. We performed a nested case-control study using data from maternal CMV antibody screening under the Cytomegalovirus in Mother and infant-engaged Virus serology (CMieV) program in Mie, Japan. Pregnant women with negative IgG antibodies at ≤20 weeks of gestation who were retested at ≥28 weeks were enrolled. The study period was divided into 2015-2019 as the pre-pandemic and 2020-2022 as the pandemic period, and the study site included 26 institutions conducting the CMieV program. The incidence rate of maternal IgG seroconversion was compared between the pre-pandemic (7008 women enrolled) and pandemic (2020, 1283 women enrolled; 2021, 1100 women; and 2022, 398 women) periods. Sixty-one women in the pre-pandemic period and five, four, and five women during 2020, 2021, and 2022, respectively, showed IgG seroconversion. The incidence rates in 2020 and 2021 were lower (p < 0.05) than that in the pre-pandemic period. Our data suggest a transient decrease in the incidence of maternal primary CMV infection in Japan during the COVID-19 pandemic, which could be due to prevention and hygiene measures taken at the population level.

Revision of Cytomegalovirus Immunoglobulin M Antibody Titer Cutoff in a Maternal Antibody Screening Program in Japan: A Cohort Comparison Involving a Total of 32,000 Pregnant Women.

Cytomegalovirus (CMV) is associated with congenital infections. We aimed to validate the revised CMV immunoglobulin (Ig) M titer cutoff for IgG avidity measurements as a reflex test in maternal screening to identify women with primary CMV infection and newborn congenital cytomegalovirus (cCMV). We screened maternal CMV antibodies (the Denka assay) in Japan, from 2017 to 2019, using a revised IgM cutoff (≥4.00 index). Participants were tested for IgG and IgM antibodies, and for IgG avidity if IgM levels exceeded the cutoff. We compared these with corresponding results from 2013 to 2017 based on the original cutoff (≥1.21) and recalculated using the revised cutoff. Newborn urine CMV DNA tests were performed for women with low avidity (≤35.0%). Among 12,832 women screened in 2017-2019, 127 (1.0%) had IgM above the revised cutoff. Thirty-five exhibited low avidity, and seven infants developed cCMV. Of 19,435 women screened in 2013-2017, 184 (1.0%) had IgM above the revised cutoff, 67 had low avidity, and 1 had cCMV. The 2017-2019 results were not significantly different from the 2013-2017 results. The revised IgM cutoff improves maternal screening in identifying primary infection and newborn cCMV; however, further study related to other assays than Denka is required.

Characteristics and serology of pregnant women with cytomegalovirus immunoglobulin G seroconversion during pregnancy in Japan.

OBJECTIVE: Investigate the characteristics and serology of pregnant women with cytomegalovirus (CMV) immunoglobulin (Ig)G seroconversion during pregnancy to understand the risk factors associated with primary CMV infection and the occurrence of fetal congenital CMV infection. MATERIALS AND METHODS: We retrospectively studied 3202 pregnant women who were CMV IgG-negative in early pregnancy and were retested for IgG in late pregnancy. Characteristics were compared between participants with and without IgG seroconversion, and serological parameters were compared between participants with and without fetal congenital CMV infection. RESULTS: Twenty-six participants showed CMV IgG seroconversion and fifteen showed fetal congenital CMV infection. Seroconversion rates were significantly higher in teens (5.0%) than in older women (20s: 0.8%; 30s and over: 0.6%) (p < 0.001). Titers of CMV IgM at IgG seroconversion were higher in women without (median 8.66) than with (median 6.54) congenital infection (p = 0.045). The congenital infection rate was high when IgM titers at IgG seroconversion were low (47.1% with 4.00-12.00 titers and 100% with 1.21-3.99 IgM titers) (p = 0.048). CONCLUSIONS: Nulliparous pregnant teenagers have a high risk of CMV IgG seroconversion and the CMV IgM titer at IgG seroconversion may help predict the occurrence of fetal congenital CMV infection.

Primary cytomegalovirus infection during pregnancy and congenital infection: a population-based, mother-child, prospective cohort study.

OBJECTIVE: This study assessed maternal cytomegalovirus antibodies, and the occurrence of primary and congenital cytomegalovirus infections, and risk factors of congenital infection after a maternal primary infection. STUDY DESIGN: We included 19,435 pregnant women in Japan, who were tested for serum cytomegalovirus antibodies before 20 gestational weeks. Immunoglobulin (Ig) G avidity was evaluated in women with both IgG and IgM antibodies; tests were repeated at ≥28 gestational weeks among women without IgG and IgM antibodies. RESULT: Primary and congenital infections were 162 and 23 cases, respectively. The risk ratios for congenital infection were 8.18 (95% confidence interval: 2.44-27.40) in teenage versus older women, and 2.25 (95% confidence interval: 1.28-3.94) in parity ≥ 2 versus parity ≤ 1. Of 22 live birth congenital infection cases, three had abnormal neurological findings. CONCLUSION: We demonstrated teenage and parity ≥ 2 pregnant women as risk factors of post-primary congenital infection.