As the COVID-19 pandemic began spreading across the United States, public health professionals scrambled to get ahead of the virus. Early in the pandemic, scientists at the Wadsworth Center, New York State Department of Health, came up with an innovative idea to expand their state’s COVID surveillance capacity by using a tool already at their fingertips.
As part of every state’s public health newborn screening program, which tests for a number of treatable medical conditions, a small amount of blood is collected on a blood spot card from every baby before hospital discharge. In New York, the unused portion of the blood spot sample is then stored.
Because a mother’s antibodies are transferred to her infant during pregnancy, testing for antibodies in newborn blood spots provides information about previous viral infections in the mother. Wadsworth Center scientists sought to determine if testing dried blood spots for antibodies might be useful in tracking the introduction and spread of SARS-CoV-2 in New York.
Technicians are trained to use the instrument that reports the amount of antibodies in each sample. Photo by Linda Styer
Dried blood spot samples are loaded onto robotic instruments. Each instrument can test 1,392 samples at a time. Photo by Linda Styer
A technician prepares reagents to load onto the robotic instruments. Photo by Mike Wren/NYSDOH
A technician mixes dried blood spot liquid prior to adding it to test reagents. Photo by Mike Wren/NYSDOH
Wadsworth Center scientists had already developed a SARS-CoV-2 antibody test for blood serum, and a team led by Dr. Linda Styer, associate director of the Bloodborne Viruses Laboratory at the Wadsworth Center, rapidly adapted it for high-volume testing of dried blood spots. Early in the pandemic, Dr. Styer’s team used this system to test by hand more than 57,000 dried blood samples collected from residents to assess the spread of SARS-CoV-2 across the state.
To gather more historical data and to continue to monitor the spread of the virus, Dr. Michele Caggana, director of New York State’s Newborn Screening Program at the Wadsworth Center, developed a plan and obtained approval from the New York State Department of Health’s Institutional Review Board to test remnant deidentified newborn blood spots submitted to the newborn screening program from November 2019 to November 2021.
“To perform this study, we automated our antibody test, so we could test thousands of samples each day. We also expanded the test to detect antibodies to different parts of the SARS-CoV-2 virus,” Dr. Styer said. “This allows for earlier detection of antibody responses and provides better discrimination with closely related antibodies to other coronaviruses.”
Dr. Linda Styer, associate director of the Bloodborne Viruses Laboratory at the Wadsworth Center. Photo courtesy of Linda Styer
Dr. Michele Caggana, director of New York State's Newborn Screening Program at the Wadsworth Center. Photo courtesy of Michele Caggana
With the support of the CDC Foundation, Wadsworth Center scientists sampled more than 517,000 existing blood spot samples from that two-year period, from more than 415,000 individual newborns.
“We were able to go back and test newborn screening samples starting from November 2019, prior to the official emergence of SARS-CoV-2 in China, and show that antibodies weren’t detected in newborns until March 2020, one to two months after the first cases were diagnosed in pregnant women in New York State,” Dr. Styer said.
These data, recently published in JAMA Network Open, showed how the different waves of SARS-CoV-2 infections had unique geographic patterns across the state. By testing for antibodies to the SARS-CoV-2 spike protein–the target protein currently used in the COVID-19 vaccines–the study was also able to show vaccine uptake over time, all using the available newborn blood spot specimens.
Because every state collects blood spot specimens through newborn screening programs, SARS-CoV-2 antibody surveillance using these specimens may be applicable to other locations. The technology does not allow for variant-specific analyses, and the data cannot be used to identify specific individuals or determine the total number of people infected with SARS-CoV-2 over time because antibodies wane. Still, this method provides an accurate, unbiased window into specific communities as more people rely on at-home diagnostic tests and do not report positive cases to local health departments.
Many infectious diseases that affect pregnant women could be surveilled using this approach.
“Many infectious diseases that affect pregnant women could be surveilled using this approach. In fact, we already screen for HIV exposure by this technique,” Dr. Caggana said. “This could include new emerging diseases that affect the whole population, like SARS-CoV-2, or diseases that are of particular interest for pregnancy, like hepatitis C virus, rubella, toxoplasmosis, cytomegalovirus or herpes simplex virus.”
Through the support of the CDC Foundation, this efficient, low-cost method of processing existing blood samples is allowing scientists to track vaccine uptake in pregnant women–who are among the most at-risk populations for COVID-19 infections. As future public health challenges emerge, this blood spot surveillance provides an important new tool for health departments to quickly identify and track emerging infections, conditions or exposures of public health concern, creating a healthier future for us all.
