In the United States, two types of COVID-19 vaccines are recommended: the messenger ribonucleic acid (mRNA) vaccine and a protein subunit vaccine. Both are considered safe during all stages of pregnancy and are recommended to help safeguard both maternal and infant health.

Study of 434 Toddlers

The investigation was conducted by researchers within the Maternal-Fetal Medicine Units Network. The team evaluated 434 children between 18 months and 30 months of age for signs of autism and other developmental concerns.

The study was prospective, multi-center, and observational, and took place between May 2024 and March 2025. Half of the children (217) were born to mothers who received at least one dose of an mRNA COVID-19 vaccine either during pregnancy or within 30 days before becoming pregnant. The remaining 217 children were born to mothers who did not receive an mRNA vaccine during or within 30 days prior to pregnancy.

“Neurodevelopment outcomes in children born to mothers who received the COVID-19 vaccine during or shortly before pregnancy did not differ from those born to mothers who did not receive the vaccine,” said senior researcher George R. Saade, MD, Professor and Chair of Obstetrics and Gynecology, and Associate Dean for Women’s Health, at Macon & Joan Brock Virginia Health Sciences at Old Dominion University in Norfolk, VA.

How Researchers Compared Developmental Outcomes

To make the comparison as accurate as possible, vaccinated mothers were paired with unvaccinated mothers based on where they delivered (hospital, birth center, etc.), the date of delivery, insurance status, and race. Certain pregnancies were excluded from both groups, including those that ended before 37 weeks, involved multiple babies, or resulted in a child with a major congenital malformation.

When the children reached 1 ½ — 2 ½ years of age, researchers assessed their development using the Ages and Stages Questionnaire Version 3. This screening tool measures progress in five areas: communication, gross motor skills, fine motor skills, problem solving, and personal social interaction. The team also reviewed results from the Child Behavior Checklist, Modified Checklist for Autism in Toddlers, and the Early Childhood Behavior Questionnaire to further evaluate behavioral and developmental patterns.

“This study, conducted through a rigorous scientific process in an NIH clinical trials network, demonstrates reassuring findings regarding the long-term health of children whose mothers received COVID-19 vaccination during pregnancy,” said Brenna L. Hughes, MD, MSc, Edwin Crowell Hamblen Distinguished Professor of Reproductive Biology and Family Planning and Interim Chair of the Department of Obstetrics and Gynecology at Duke University in Raleigh, NC.

Funding and Disclosure

The study was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development. The authors noted that the conclusions presented are their own and do not necessarily reflect the official views of the National Institutes of Health.

Oral abstract #8 “Association between SARS-CoV-2 vaccine in pregnancy and child neurodevelopment at 18-30 months” will be published in the February 2026 issue of PREGNANCY, the official peer-reviewed medical journal of the Society for Maternal-Fetal Medicine.   

To accomplish this, the researchers created a machine learning platform called SIGNET. Unlike traditional tools that only detect genes that appear to move together, SIGNET is designed to uncover true cause-and-effect relationships. Using this approach, the team identified important biological pathways that may contribute to memory loss and the gradual breakdown of brain tissue.

The findings were published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association. The study also highlights newly identified genes that could become promising targets for future treatments. Funding support came in part from the National Institute on Aging and the National Cancer Institute.

Why Understanding Gene Control Matters in Alzheimer’s

Alzheimer’s disease is the leading cause of dementia and is expected to affect nearly 14 million Americans by 2060. Although scientists have linked several genes to the disease, including APOE and APP, they still do not fully understand how these genes interfere with normal brain function.

“Different types of brain cells play distinct roles in Alzheimer’s disease, but how they interact at the molecular level has remained unclear,” said Min Zhang, co-corresponding author and professor of epidemiology and biostatistics. “Our work provides cell type-specific maps of gene regulation in the Alzheimer’s brain, shifting the field from observing correlations to uncovering the causal mechanisms that actively drive disease progression.”

How SIGNET Reveals Cause and Effect Between Genes

To build these detailed maps, the team analyzed single-cell molecular data from brain samples donated by 272 participants enrolled in long-term aging studies known as the Religious Orders Study and the Rush Memory and Aging Project. SIGNET was designed as a scalable, high-performance computing system that combines single-cell RNA sequencing with whole-genome sequencing data. This integration allowed the researchers to detect cause-and-effect relationships among genes across the entire genome.

Using this method, they constructed causal gene regulatory networks for six major brain cell types. This made it possible to determine which genes are likely directing the activity of others, something conventional correlation-based methods cannot reliably accomplish.

“Most gene-mapping tools can show which genes move together, but they can’t tell which genes are actually driving the changes,” said Dabao Zhang, co-corresponding author and professor of epidemiology and biostatistics. “Some methods also make unrealistic assumptions, such as ignoring feedback loops between genes. Our approach takes advantage of information encoded in DNA to enable the identification of true cause-and-effect relationships between genes in the brain.”

Major Genetic Rewiring in Excitatory Neurons

The researchers found that the most significant gene disruptions occur in excitatory neurons — the nerve cells that send activating signals — where nearly 6,000 cause-and-effect interactions revealed extensive genetic rewiring as Alzheimer’s progresses.

The team also identified hundreds of “hub genes” that function as central regulators, influencing many other genes and likely playing an important role in harmful changes in the brain. These hub genes could become valuable targets for earlier diagnosis and future therapies. The study further uncovered new regulatory roles for well-known genes such as APP, which was shown to strongly control other genes in inhibitory neurons.

To strengthen their conclusions, the researchers validated their findings using an independent set of human brain samples. This additional confirmation increases confidence that the observed gene relationships reflect genuine biological mechanisms involved in Alzheimer’s disease.

Beyond Alzheimer’s, SIGNET may also be applied to the study of other complex diseases, including cancer, autoimmune disorders and mental health conditions.

The study found that middle age and older adults at elevated risk for cardiometabolic disease benefited from extending their overnight fasting window by roughly two hours. They also avoided food and dimmed lights for three hours before going to sleep. These changes led to measurable improvements in heart and metabolic markers during sleep and throughout the following day.

“Timing our fasting window to work with the body’s natural wake-sleep rhythms can improve the coordination between the heart, metabolism and sleep, all of which work together to protect cardiovascular health,” said first author Dr. Daniela Grimaldi, research associate professor of neurology in the division of sleep medicine at Northwestern University Feinberg School of Medicine.

The findings were published Feb. 12 in Arteriosclerosis, Thrombosis, and Vascular Biology, a journal of the American Heart Association.

“It’s not only how much and what you eat, but also when you eat relative to sleep that is important for the physiological benefits of time-restricted eating,” said corresponding author Dr. Phyllis Zee, director of the Center for Circadian and Sleep Medicine and chief of sleep medicine in the department of neurology at Feinberg.

Why Cardiometabolic Health Matters

Earlier data show that only 6.8% of U.S. adults had optimal cardiometabolic health in 2017 to 2018. Poor cardiometabolic health raises the risk of chronic conditions such as type 2 diabetes, non-alcoholic fatty liver disease, and cardiovascular disease.

Time-restricted eating has grown in popularity because studies suggest it can improve cardiometabolic markers and sometimes match the benefits of traditional calorie restricted diets. However, most research has concentrated on how long people fast rather than how well that fasting window aligns with sleep timing, which is crucial for metabolic regulation.

With nearly 90% adherence in this trial, the researchers believe anchoring time-restricted eating to the sleep period may be a realistic and accessible non-pharmacological approach, especially for middle age and older adults who face higher cardiometabolic risk.

The team plans to refine this protocol and expand testing in larger multi-center trials.

Blood Pressure, Heart Rate, and Blood Sugar Improvements

The 7.5 week study compared individuals who stopped eating at least three hours before bedtime with those who maintained their usual eating habits. Those who adjusted their timing experienced several meaningful changes.

Nighttime blood pressure decreased by 3.5%, and heart rate dropped by 5%. These shifts reflected a healthier daily pattern, with heart rate and blood pressure rising during daytime activity and falling at night during rest. A stronger day night rhythm is associated with better cardiovascular health.

Participants also demonstrated improved daytime blood sugar control. When given glucose, their pancreas responded more effectively, suggesting improved insulin release and steadier blood sugar levels.

The trial included 39 overweight/obese adults (36 to 75 years old). Participants were assigned either to an extended overnight fasting group (13 to 16 hours of fasting) or to a control group that maintained a habitual fasting window (11 to 13 hours). Both groups dimmed lights three hours before bedtime. The intervention group consisted of 80% women.

Funding: NIH/National Heart, Lung and Blood Institute, National Institute on Aging, NIH/National Center for Advancing Translational Sciences (NCATS)

“Sperm metabolism is special since it’s only focused on generating more energy to achieve a single goal: fertilization,” said Melanie Balbach, an assistant professor in the Department of Biochemistry and Molecular Biology and senior author of the study.

Before ejaculation, mammalian sperm remain in a low energy state. Once inside the female reproductive tract, they rapidly transform. They begin swimming more forcefully and adjust the outer membranes that will eventually interact with the egg. These changes demand a sudden and significant rise in energy production.

“Many types of cells undergo this rapid switch from low to high energy states, and sperm are an ideal way to study such metabolic reprogramming,” Balbach said. She joined MSU in 2023 to expand her pioneering work on sperm metabolism.

Tracking the Fuel That Powers Fertilization

Earlier in her career at Weill Cornell Medicine, Balbach helped show that blocking a critical sperm enzyme caused temporary infertility in mice. That discovery highlighted the possibility of nonhormonal male birth control.

Although scientists understood that sperm require large amounts of energy to prepare for fertilization, the exact mechanism behind this surge remained unclear until now.

Working with collaborators at Memorial Sloan Kettering Cancer Center and the Van Andel Institute, Balbach’s team developed a method to follow how sperm process glucose, a sugar they absorb from their surroundings and use as fuel.

By mapping glucose’s chemical path inside the cell, the researchers identified clear differences between inactive sperm and those that had been activated.

“You can think of this approach like painting the roof of a car bright pink and then following that car through traffic using a drone,” Balbach explained.

“In activated sperm, we saw this painted car moving much faster through traffic while preferring a distinct route and could even see what intersections the car tended to get stuck at,” she said.

Using resources such as MSU’s Mass Spectrometry and Metabolomics Core, the team assembled a detailed picture of the multi step, high energy process sperm rely on to achieve fertilization.

Aldolase and the Control of Sperm Metabolism

The study found that an enzyme known as aldolase plays a key role in converting glucose into usable energy. Researchers also learned that sperm draw on internal energy reserves they already carry when their journey begins.

In addition, certain enzymes act like regulators, directing how glucose moves through metabolic pathways and influencing how efficiently energy is produced.

Balbach plans to continue investigating how sperm rely on different fuel sources, including glucose and fructose, to meet their energy demands. This line of research may affect multiple areas of reproductive health.

Implications for Infertility and Nonhormonal Birth Control

Infertility affects about one in six people worldwide. Balbach believes that studying sperm metabolism could lead to better diagnostic tools and improved assisted reproductive technologies.

The findings may also support the development of new contraceptive strategies, particularly nonhormonal approaches.

“Better understanding the metabolism of glucose during sperm activation was an important first step, and now we’re aiming to understand how our findings translate to other species, like human sperm,” Balbach said.

“One option is to explore if one of our ‘traffic-control’ enzymes could be safely targeted as a nonhormonal male or female contraceptive,” she added.

Most efforts to create male contraceptives have focused on stopping sperm production. That strategy has drawbacks. It does not provide immediate, on demand infertility, and many options rely on hormones that can cause significant side effects.

Balbach’s latest work suggests an alternative. By targeting sperm metabolism with an inhibitor based, nonhormonal approach, it may be possible to temporarily disable sperm function when desired while minimizing unwanted effects.

“Right now, about 50% of all pregnancies are unplanned, and this would give men additional options and agency in their fertility,” Balbach said. “Likewise, it creates freedom for those using female birth control, which is hormone-based and highly prone to side effects.

“I’m excited to see what else we can find and how we can apply these discoveries.”

Why This Matters

• Sperm must dramatically boost their energy levels to complete the demanding journey to an egg and achieve fertilization.
• Scientists have now uncovered how sperm tap into glucose in their surroundings to power this surge, revealing the fuel source behind their rapid transformation.
• This discovery deepens our understanding of reproductive biology and could open the door to better infertility treatments and innovative, nonhormonal birth control options.

The research was published in the Proceedings of the National Academy of Sciences and supported by the National Institute of Child Health and Human Development.