Database of diseases - Flu and cold

RSV virus (Respiratory Syncytial Virus) - is a RNA virus size 150 - 300 nm, belonging to the family Paramyxoviridae, genus Pneumovirus. Currently, two types of virus (A and B) are distinguished, and numerous serotypes within them.


Dangerous for infants and older children
 
According to the World Health Organization (WHO), respiratory syncytial virus (RSV) infects the entire global population of children, both elderly and infants. Almost 100 percent children under two years of age in the US undergo at least one infection with the RSV virus. It is estimated that globally, up to one million child deaths may be directly or indirectly related to RSV infection.



How to recognize the symptoms of RSV infection?

The disease starts with runny nose, cough, moderate fever and these symptoms subside to 2 weeks. Symptoms differ from the typical symptoms of infection of a cold-catarrhal infection, in that they last a week longer! Inflammation of mucous membranes, runny nose, cough fever results from the pathomechanism of RSV virus replication in the child's body, during which neighboring cells merge into large multinuclear syndrome (syncytia)


How often does he infect?

High infectivity causes RSV to be responsible for the annual number of respiratory infections in infants and older children. The ignition of children in crèches in case of epidemics caused by this virus reaches 100%! And in kindergartens up to 50%. Almost 100 percent children under two years of age in the US undergo at least one infection with the RS virus. It is transmitted by droplets and by direct contact with infected surfaces. For the home environment, the virus is most often transmitted by older siblings who bring it from school or kindergarten.


Infections in Poland

The first multicentre epidemiological study carried out in Poland in the autumn and winter of 2000/2001 showed that 41.3 percent of of 179 children under two years of age hospitalized for lower respiratory tract infection were infected with RS virus. These data confirm that this virus is one of the most common pathogenic agents that cause respiratory tract infections among hospitalized infants and newborns.


Short-term complications of acute RSV infections

Respiratory infections caused by the RS virus in many cases cause serious complications. The most common short-term complications with RS virus infection include apnea, which occurs in about 20% of cases. hospitalized children and usually refers to the early phase of the disease.


The deadly virus RSV

According to data from the World Health Organization (WHO), every child under the age of 5 suffers about 5 times a year, and from 600,000 to 1,000,000 deaths of children are directly or indirectly related to RS virus infection. According to European data, the mortality rate of children from high-risk groups with confirmed RSV infection is 1-3%.








Long-term complications of RSV infections

- hypersensitivity of the airways manifested by exhaustion
- bronchial asthma.



The most serious complications of RSV infection can lead to:

- laryngotracheitis,
- acute otitis media,
- bronchitis - leading to obstruction,
- complete obstruction of the airways, which in turn may lead to pneumonia, as well as the ganglia syndrome.

Inflammation of the middle ear Inflammation of the paranasal sinuses Laryngitis in children Bronchitis Pneumonia

RSV virus and asthma

Currently, the relationship between the risk of bronchial asthma and the early infancy of RSV infection is increasingly emphasized.The follow-up studies in the US covered a period of 7 years and their aim was to determine the occurrence of symptoms of exhaust dyspnea and bronchial asthma in the first, third and seventh years of life. The results left no doubt that infection with the RS virus predisposes to the occurrence of exhaustive dyspnoea and bronchial asthma at the age of seven.


Risk groups complication

Based on the observation of the frequency of RS infections and the course of the acute phase of infection, three risk groups were identified, i.e. groups of children most exposed to the negative effects of infection (including the possibility of death). These are:
- children with prematurity and bronchopulmonary dysplasia,
- children with congenital heart defects,
- children suffering from cystic fibrosis


Prematurity and RS virus

Prematurity and RS virus infection are a serious threat to the health and life of an infant. Infants with pre-natal history (born before 32 weeks of gestation) are 10 times more likely to have lower respiratory tract infections compared to those born at time. The course of infection in this group is severe, and these children usually require treatment under intensive care consisting in administering oxygen, using replacement breath, administering bronchodilator and intravenous fluids. Such treatment can last up to several weeks.


Broncho-pulmonary dysplasia in premature babies (BPD)

Due to the better perinatal care in Poland, the survival limits of premature babies have clearly shifted towards the earlier weeks of intrauterine life and lower birth weight of the newborn. The lungs of un-infants are often underdeveloped. A consequence of the treatment of respiratory disorders in preterm infants in the neonatal period is chronic lung disease, also known as bronchopulmonary dysplasia (BPD - bronchopulmonary dysplasia). Another factor contributing to the severe RS virus infection is that maternal antibodies that help the neonatal sheath against diseases caused by the RS virus in an infant born ahead of time do not have the chance to achieve a protective level.


Infants with bronchopulmonary dysplasia are severely infected with RS virus

Infant research with the history of BPD showed that 90 percent. of them, during the winter season, they suffered from acute inflammation of the airways, 59% of which it was caused by the RS virus. The stay in the hospital and numerous complications occurred in 69% who had an infection of the lower respiratory tract. In the case of a severe course of infection, this treatment usually takes place under intensive care. Therefore, the best way to protect your child is to prevent RSV infection.

In Poland, the number of premature babies is about 50,000. annually.

This number includes children with low birth weight, which currently constitute about 6 percent. the total number of live births. It is 2 percent. more than in Western European countries. With extremely low birth weight - below 1000g, over 1,000 children are born each year. The number of children diagnosed with bronchopulmonary dysplasia is estimated at approximately 400 new cases per year, the majority of whom are premature babies born before the 32nd week of pregnancy. It is estimated that the increment of new BPD cases is around 25 percent. annually.

 

RSVand breastfeeding

Some scientists have also suggested that breastfeeding may contribute to a lower incidence of airway inflammation caused by the RS virus. However, these hypotheses have never been fully proven. Therefore, more attention was paid to the prevention of RSV infection than to treatment.


Prevention of RSV infections

A few years ago, new prevention options emerged when the humanized monoclonal anti-RSV antibody was allowed to be used. Randomized multicentre studies on the effectiveness of this prophylaxis gave very convincing results; 55 percent reduction of hospitalization due to RSV infection, 78 percent reduction of hospitalization for RSV among premature infants without BPD and 39% reduction of hospitalization among infants with BPD. The conclusions are clear: monthly prophylaxis is an effective form of prophylaxis against RSV infections. Therapy begins one month before the start of the period of increased morbidity caused by the RS virus and continues throughout the autumn-winter-spring period.

Treatment of RSV infections

Because chest x-ray may suggest bacterial pneumonia, it often happens that infected children get antibiotics. As a rule, however, it does not bring any improvement and can often be a cause of worsening the course of the disease. The issue of antibiotic therapy was even more severely questioned after the publication of the results of multi-center randomized studies, which showed the absence of any positive effect of this treatment.





Factors determining the high risk of developing RSV infection in a child

- Unblocking from a neonatal unit (neonatal ICU) just before or during the RS virus season

- Exposure to environmental toxins (especially passive smoking)

- Essential diseases (e.g., neurological disorders)

- Large number of household members (> 4-6 people)

- Dividing a bedroom by an infant with siblings or other infected members of the family

- A mother from the group of multiple births

- Siblings at school age

 

Author: Dr n. Med. Marek Migdal; INSTITUTE "Monument - Children's Health Center"
 

Prophylaxis of RS virus infections - for further information:
Dr n. Med. Marek Migdał, RSV Center, Institute "Memorial - Children's Health Center", tel./fax (022) 815 18 70