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  • RSV is spreading in the U.S. this winter.
  • A new study sheds light on how the virus may cause neurological symptoms.
  • The virus, which is the most common cause of lower respiratory tract infections, can infect nerve cells and trigger inflammation.

A recent study has revealed why respiratory syncytial virus (RSV) may cause neurological symptoms in certain individuals.

The virus, which is the most common cause of lower respiratory tract infections, can infect nerve cells and trigger inflammation that may contribute to neurological symptoms.

The report is the first study to show that RSV can enter nerve cells.

Many children with RSV develop mild symptoms, including cough and fever. However, according to past research some young children may develop encephalopathy, a brain condition that can lead to confusion, memory loss or cognitive difficulties after contracting RSV.

The virus has also been detected in the spinal fluid of children with seizures.

“Our study, recently published in The Journal of Infectious Diseases, is the first to prove that RSV, one of the most common respiratory viruses in young children and the elderly, can infect peripheral nerves and may provide the clearest link between RSV and reported neurological symptoms,” one of the study’s co-authors Dr. Giovanni Piedimonte, the vice president for research and professor of pediatrics, biochemistry and molecular biology at Tulane University, told Healthline.

To understand if and how RSV affects the nervous system, the researchers studied nerve cultures grown from stem cells and rat embryos.

They found that the virus is able to directly infect parts of the nervous system, including peripheral nerve cells, macrophages, and dendritic cells.

RSV infection was also associated with a strong inflammatory response — the release of infection-fighting proteins called chemokines — and changes in nerve function.

With low levels of viral infection, the nerves became hyperreactive, and with higher levels of viral infection, there was nerve degeneration and neurotoxicity.

The researchers suspect that the increased nerve sensitivity may explain why some children develop asthma.

Based on the findings, the researchers theorize that by infecting the peripheral nerves, RSV can reach the spinal cord, pass the blood-brain barrier, get into the central nervous system, and infect the brain.

“This study suggests RSV may affect the nervous system, highlighting the importance of ongoing research and preventative measures like new vaccines,” says Dr. Daniel Ganjian, FAAP, a board-certified pediatrician at Providence Saint John’s Health Center in Santa Monica, CA.

Ganjian was not involved with the study.

The study is the first to show that the respiratory virus can infect neural cells.

“This finding is somewhat surprising because for many years since its discovery in 1956, RSV was thought to be able to infect only the respiratory tract,” says Piedimonte.

Other respiratory viruses, such as the measles virus, are well known to infect central nervous tissue, according to Dr. Richard Martinello, Yale Medicine infectious diseases specialist and professor of medicine at Yale School of Medicine.

Martinello was not involved in this study.

The long-standing belief with RSV was that the body’s inflammatory response damaged nerve cells.

Inflammation in the nervous system can impact cellular function, “limiting or preventing them from performing their normal ‘job,’ leading to problems such as a depressed level of cognition and/or alertness and possibly also leading to seizure activity,” says Martinello.

Now, it appears that not only does RSV trigger inflammation, but the virus can also directly penetrate the nervous system.

Piedimonte’s lab has previously discovered that RSV is able to infect tissues outside of the lungs, including human bone marrow.

“There is growing evidence that RSV can spread via the blood circulation outside of the initial focus of infection in the respiratory tract and land into other tissues and organs causing inflammation and clinical symptoms,” he said.

This study further highlights the importance of the RSV vaccines recently approved for older adults and pregnant people, says Piedimonte.

In certain cases, such as if the mother did not receive the vaccine, children aged younger than 8 months are advised to receive nirsevimab, a monoclonal antibody that can help to protect against RSV, during their first RSV season.

Data suggests the maternal vaccine can reduce a baby’s risk of being hospitalized from RSV by 57% in the first six months after birth.

The vaccines are also effective at preventing infection in infants.

“By preventing infection due to RSV, it can prevent complications related to infection,” says Martinello.

Future studies are needed to investigate how RSV interacts with the central nervous system and whether it could lead to neurological or developmental disorders.

“This is a developing field, and more research is needed to fully understand RSV’s long-term effects and best preventive strategies,” Ganjian said.

A new study has revealed that respiratory syncytial virus (RSV), the most common cause of lower respiratory tract infections, can infect nerve cells and trigger inflammation that may contribute to neurological symptoms. The study is the first to show that RSV can directly infect nerve cells. The findings also underscore the importance of the recently approved RSV vaccines, as they can help prevent serious outcomes in those who are at-risk, including babies.