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Respiratory Syncytial Virus: What Are The Symptoms And Risk Factors One Should Know
Respiratory Syncytial Virus (RSV) is a viral infection that affects the respiratory tract. While it usually causes mild cold-like symptoms in healthy individuals, it can lead to more severe respiratory issues, especially in infants, older adults, and individuals with weakened immune systems.
Even in India, RSV is widespread. According to research published in the National Library of Medicine, RSV detection rates in younger children, ages zero to five, range from 2.1% to 62.4%. This number is higher than in other age groups.
Symptoms of RSV Infection CoughingPersistent coughing, often accompanied by mucus production, is a common symptom of RSV infection.
CongestionNasal congestion and difficulty breathing may occur, particularly in infants who have smaller airways.
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FeverA fever is a typical response to viral infections, and RSV is no exception. It can range from mild to moderate.
Wheezing and difficulty breathing, especially during exhaling, can be observed, particularly in infants and young children.
Runny NoseExcessive nasal discharge is common, contributing to congestion and discomfort. As per MayoClinic, the fluid might vary from thin and transparent to thick and yellow-green. The fluid may trickle or stream from the nose, down the back of the throat, or both. Postnasal drip occurs when it flows down the back of the throat.
Decreased AppetiteIndividuals, especially infants, may show a decreased interest in feeding due to difficulty breathing.
Bluish Skin Colour (Cyanosis)In severe cases, a bluish tint to the skin, particularly around the lips and nails, may indicate inadequate oxygen levels.
Risk Factors for RSV Infection AgeInfants and young children, especially those under six months of age, are at higher risk due to their immature immune systems. According to the Centers of Disease Control and Prevention, if someone is 60 or older, there is a vaccine available to protect you from severe RSV.
Chronic Lung DiseaseIndividuals with chronic lung conditions, such as asthma or bronchopulmonary dysplasia, are at an increased risk of complications.
Heart DiseasePeople with congenital heart disease or other heart-related conditions are at higher risk.
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Weakened Immune SystemIndividuals with weakened immune systems, whether due to medical conditions or medications, may be more vulnerable to severe RSV infections.
Exposure to Secondhand SmokeExposure to tobacco smoke, especially in infants, increases the risk of RSV infection and complications.
Crowded Living ConditionsPeople living in crowded or communal settings, such as daycare centers or nursing homes, may have an increased risk of exposure.
Respiratory Syncytial Virus (RSV) infection can range from mild cold-like symptoms to severe respiratory distress, especially in high-risk populations. Recognizing the symptoms and understanding the risk factors is crucial for timely intervention and management. If you suspect an RSV infection, particularly in infants or those with underlying health conditions, seeking prompt medical attention is essential for appropriate care and support.
RSV: Preventable And Treatable Infection Of Young And Old
Respiratory syncytial virus (RSV) affects infants, young children, and older adults, particularly those with compromised respiratory or cardiovascular health. Every year RSV causes approximately 58,000 to 80,000 hospitalizations and 100 to 300 deaths in children aged less than 5 years, as well as 60,000 to 160,000 hospitalizations and 6,000 to 10,000 deaths among adults aged 65 years and older.1
Most recent studies reveal a high threat of this infection in the southeastern region of the United States. A landmark study on patients under the age of 5 years suggested that RSV infection is the single greatest causative factor of pneumonia in this age group in the US.2 In another study of adults aged 60 years and older hospitalized with RSV infection, 66% developed pneumonia.3
Risk Factors and Transmission for RSVIn children, risk factors for infection include prematurity at birth, low birthweight (<2500 g), underlying immunologic disorders (either natural or acquired), genetic and chromosomal abnormalities (eg, Down syndrome), the presence of other pulmonary disease processes, neoplasias, and defects of the heart and/or lung structures. In older adults, immunosuppression, chronic obstructive pulmonary disease (COPD), and heart failure increase susceptibility to RSV infection.4
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Diagnosis of RSV is made by rapid antigen detection tests (RADTs), direct fluorescent antibody (DFA), polymerase chain reaction (PCR), and viral cultures of nasopharyngeal swabs and aspirates.
Transmission of RSV takes place via droplets and contaminated surfaces. The virus can survive for many hours on hard surfaces such as tables and crib rails. Those infected with RSV are usually contagious for 3 to 8 days after showing symptoms. However, people can spread the disease in the prodromal phase, which is 1 to 2 days before demonstration of symptoms. Some infants and immunosuppressed adults can continue to spread the virus for as long as 4 weeks. Children are often exposed to and infected with RSV outside the home, such as in school or childcare centers.5
Clinical Manifestations of RSVSymptoms of RSV infection include fever, cough, sneezing, and wheezing. Bronchiolitis is common in younger children with RSV. Clinically, bronchiolitis is characterized by expiratory breathing difficulty in infants. Other signs and symptoms include cough, tachypnea, hyperinflation, intercostal retractions, and wheezing.6 Pneumonia is a common sequela of RSV infection in both children and adults; it is most commonly evidenced by fever, cough, hypoxia, cyanosis, and pulmonary crackles. Infection can lead to complications that require supplemental oxygen, intensive care unit (ICU) admission, and mechanical ventilation. In older adults, particularly those over age 60 with underlying comorbidities, RSV can cause exacerbations of heart failure and COPD.3,7
Pathophysiologic Mechanism of RSVIn children, particularly in premature infants, the immaturity of the pulmonary immune system is partly responsible for increased susceptibility to RSV infection. A genetic predisposition may also play a role in the development of severe lower respiratory infection and hyper-reactivity of the airway. It is believed that the infant's lungs are stimulated by a T-helper 2 cell inflammation reaction against RSV. There is a deficient response by interferons, which should naturally fight viruses, and increased response by the inflammatory mediators, interleukins. This results in goblet cell hyperplasia, increased mucus production, and bronchospasm.8,9
The mechanism by which RSV causes lower respiratory illness in older adults is less clear. Older adults are known to be less immunocompetent than younger adults and children. It is believed they possess lower RSV-specific serum immunoglobulin (Ig) and nasal IgA titers, which increases their susceptibility.10 Older patients with COPD have hyper-reactive airways and RSV, as well as other pathogens, can trigger an exacerbation. RSV infection causes mucous overproduction, reduced mucociliary clearance, and subsequent airway obstruction in those with COPD. Those with heart failure are in a precarious position where inflammation of the lungs can cause hypoxia, which can lead to decompensation of cardiac function.11 Importantly, natural infection does not provide long-lasting immunity to RSV and reinfections with RSV can occur throughout life.12
Diagnosis of RSVRespiratory syncytial virus can be detected by rapid antigen detection tests (RADTs), direct fluorescent antibody (DFA), and polymerase chain reaction (PCR) testing on nasopharyngeal swabs and aspirates (Figure). Viral cultures can be done, however, turn-around time is up to 7 days. If RSV is the main concern, DFA testing or RADTs are most commonly recommended, particularly for infants and children. If other respiratory viruses are also of concern, PCR panels are available that test for a spectrum of respiratory viruses, including RSV. PCR testing is generally more reliable in adults and is recommended for all hospitalized or immunocompromised patients.13
Treatment of RSVTreatment for RSV infection mainly includes supportive interventions to prevent dehydration, reduce fever, and manage airway obstruction. Intravenous fluids, bronchodilators, corticosteroids, and mucolytic agents can be used to relieve symptoms. Continual monitoring of oxygenation is necessary. Supplemental oxygen should be administered if needed. Mechanical ventilation may be required in severely affected individuals.
Prevention of RSV InfectionNew prevention tools for RSV have become available according to the Centers for Disease Control and Prevention (CDC).14 These include monoclonal antibody agents and vaccines. Nirsevimab is a long-acting monoclonal antibody approved by the US Food and Drug Administration (FDA) to protect infants and young children at increased risk for severe RSV disease. Nirsevimab is safe and efficacious. In clinical trials, 1 dose of nirsevimab administered as an intramuscular injection protected infants for at least 5 months (the length of an average RSV season) and reduced the risk of severe RSV disease by about 80%.14
Another monoclonal antibody, palivizumab, is recommended by the American Academy of Pediatrics (AAP) for administration to infants and young children who are at increased risk of severe RSV disease. It is given in monthly intramuscular injections during RSV season.15
The FDA has approved two recombinant protein vaccines RSVPreF3 and RSVpreF that are approved by the FDA for use in adults aged 60 years and older to prevent RSV-associated lower respiratory tract disease. During the first RSV season after vaccination, each vaccine was more than 80% efficacious in preventing RSV-associated lower respiratory tract disease.16
On August 21, 2023, FDA approved the RSVpreF vaccine for use in pregnant women during weeks 32 through 36 of gestation for the prevention of RSV-associated lower respiratory tract disease in infants from birth through 6 months of age.17
ConclusionRespiratory syncytial virus affects infants, young children, and older adults, particularly those with compromised respiratory or cardiovascular health. Most recent studies reveal a high threat of this infection in the southeastern region of the United States. Diagnosis of RSV is made by rapid antigen detection tests (RADTs), direct fluorescent antibody (DFA), and polymerase chain reaction (PCR) testing on nasopharyngeal swabs and aspirates. New prevention tools for RSV include monoclonal antibody agents and vaccines. These are proving to be highly efficacious and safe for children and adults.
This article originally appeared on Clinical Advisor
RSV Can Trigger Inflammation And Nerve Damage
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.
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