NNDSS Helps Modernize Pregnancy Data
Experts from CDC’s National Center on Birth Defects and Development Disabilities support health departments to bring together data from multiple sources. These sources include case surveillance data from the National Notifiable Diseases Surveillance System (NNDSS) Bringing together multiple data sources helps experts to better understand the impact of COVID-19 on pregnant people and infants to guide public health action.
Using a system called Surveillance for Emerging Threats to Mothers and Babies Network (SET-NET), experts are gathering information on COVID-19 in pregnant people. The integration of data, such as COVID-19 case data, vital records and other data sources, into SET-NET helped determine risk factors for severe illness and death and adverse pregnancy outcomes of pregnant people with COVID-19. These data also inform messaging and guidance on how to prevent and treat COVID-19 among pregnant people.
Beyond the COVID-19 response, scientists are engaged in a leading-edge effort to identify opportunities to prevent and treat syphilis infections during pregnancy and understand the longer-term outcomes of infants born with and without congenital syphilis. Through a pilot effort with two state health departments, CDC merged NNDSS syphilis data on adults and infants to create a mother-baby-linked dataset for SET-NET. This effort can help to streamline reporting for health departments to identify parent-child pairs for surveillance. As we continue to face health threats, these efforts to improve data collection will help experts get information faster and better protect the nation.
CDC is at the forefront of modernizing public health data by linking information from different sources to answer important questions. In one effort, experts from CDC’s National Center on Birth Defects and Development Disabilities are working to bridge knowledge gaps by collaborating with health departments. This collaboration seeks to efficiently combine case surveillance data from the National Notifiable Diseases Surveillance System (NNDSS) with other data sources. This will help experts better understand the impact of COVID-19 on pregnant people and infants.
Improving Completeness of Data on COVID-19 and Pregnancy
In 2020, as COVID-19 cases escalated, pregnant people were found to be at higher risk for severe illness. Scientists quickly expanded a system already in place that uses data to identify the impact of health threats to pregnant people and their infants. The system, called the Surveillance for Emerging Threats to Mothers and Babies Network (SET-NET), supports information gathering by health departments working with CDC.
SET-NET originated from mother-infant linked surveillance established in 2016, when Zika became the first mosquito-borne virus known to cause birth defects. As SET-NET traces its beginnings to a public health emergency response, experts were ready to adapt the system to meet demands of the fast-evolving COVID-19 pandemic.
Experts quickly began working with epidemiologists to monitor existing COVID-19 data for cases among pregnant people. State and jurisdictional health departments voluntarily send case data to CDC through NNDSS, including information about pregnancy status. Early in the pandemic, pregnancy information often was incomplete. Through SET-NET, CDC worked with health departments to link data from disease surveillance, contact tracing, medical record review, laboratory testing, infant screenings, and birth records to get a clearer picture of COVID-19 on pregnancy and infant outcomes.
The collaboration between SET-NET and case data sent through NNDSS already has made an impact. The SET-NET data have helped determine risk factors for more severe illness during pregnancy and confirmed that pregnant people are at a higher risk for adverse birth outcomes from COVID-19. These findings have informed messaging and guidance on how to prevent and treat COVID-19 among pregnant people. For example, these data helped guide CDC recommendations that prioritized pregnant people for COVID-19 vaccines. SET-NET and NNDSS also collect information about demographic characteristics such as mothers’ race and ethnicity and age. These data give experts important insights about health equity among mothers and babies, including the higher burden of COVID-19 on Hispanic pregnant people.
Beyond the COVID-19 response, experts are using SET-NET to integrate data in other areas, including syphilis control and prevention. Health departments submit disease data to CDC through NNDSS. CDC uses the data and tools to merge and de-duplicate the information, making it quicker and easier for health departments to match data on the pregnant person and infant. CDC piloted the effort by partnering with health departments in Arizona and Georgia to link multiple syphilis reports among pregnant people with congenital syphilis cases in NNDSS from 2016–2021 to create a mother-baby dataset for SET-NET. The process is ongoing, and experts are now comparing the data with SET-NET submissions to determine the accuracy and completeness of the linkage.
Evaluating data completeness and streamlining work are just two ways experts are making strides toward data modernization in pregnancy reporting. They continue to work to standardize data elements across systems; improve collaboration among health departments, CDC programs, and other agencies; and build technical expertise by bringing informatics and other professionals onboard. As we continue to face health threats such as COVID-19, these efforts to improve data collection will help experts get information faster and better protect the nation.