Using Scenario Modeling to Estimate Burden of Human Parvovirus B19 and Impact of Increased B19 Detection in Pregnancy

CONTEXT: Human parvovirus B19 (B19) is a common infection that typically causes mild symptoms but can cause severe fetal complications among pregnant individuals. There are limited data to inform public health responses because B19 is not a reportable disease. OBJECTIVE: We sought to estimate the burden of B19-related pregnancy complications and impact of increasing B19 detection in both Minnesota and the United States using electronic health record data and scenario modeling. DESIGN: To estimate the burden of B19-related complications for the United States (4 000 000 annual pregnancies), a spreadsheet-based model was developed. B19 outcomes were estimated under varying scenarios of population immunity (25%-75%) and probability of infection (1%-7.5%). To evaluate the impact of increased B19 detection in pregnancy, a decision tree model compared the status quo (5% detection of cases) to a strategy that increased detection (50%). Inputs for both models were derived from published literature or expert opinion and were varied in sensitivity analyses. SETTING: Not applicable. PARTICIPANTS: Not applicable. INTERVENTION: Increasing detection of B19 infections during pregnancy. MAIN OUTCOME MEASURES: Main outcomes included number of stillbirths and intrauterine transfusions. RESULTS: For the United States nationally, the model estimated 750-2250 B19-related fetal complications annually under scenarios of 1% infection probability and 5625-16,875 with 7.5% infection probability, depending on proportion of pregnant individuals immune. Increasing the percent of maternal infections detected early from 5% to 50% could avert 42 stillbirths and lead to 35 more intrauterine transfusions under the 1% infection scenario. With the 7.5% infection scenario, 50% detection could avert 318 stillbirths and lead to 265 more transfusions annually. CONCLUSIONS: In the context of limited B19 data, this analysis aimed to support public health investigation and response by providing estimates of B19 burden in pregnancy and evaluating the potential impact of increasing early detection of B19.