A nasopharyngeal swab can accurately diagnose whether you have an RSV infection or influenza. — Bloomberg
Respiratory syncytial virus (RSV) is a common infection that affects the nose, throat and sometimes the lungs of young children and senior citizens.
Whilst the majority of RSV infections are usually mild with cold-like symptoms, they are unpredictable and can spread rapidly to the lower respiratory tract, causing lung infection (pneumonia) and/or infection of the small airway passages entering the lungs. (bronchiolitis)
In the United States, it was reported that two out of three babies were infected with RSV before they reached the age of one.
RSV was a seasonal disease that usually occurs from autumn through spring.
Infants were 16 times more likely to be hospitalised with an RSV lung infection than with influenza.
In Malaysia, an analysis of 23,306 children who presented with acute respiratory infection from 2015 to 2019 revealed that 18,538 (79.5%) tested positive for respiratory pathogens.
The most prevalent were enterovirus/rhinovirus (6,837; 29.7%), influenza virus (5,176; 22.5%) and RSV (3652; 15.9%).
Throughout the study period, RSV demonstrated the most pronounced seasonality with peak infection from July to September, unlike influenza which was detected year-round.
There was no seasonal variation in other respiratory pathogens.
The risk of RSV hospitalisation was significantly higher in children below two years old whereas hospitalisation rates for influenza peaked in children between the ages of three and six.
An earlier study reported that 26.4% of samples for respiratory virus detection from children five years old and below were positive for the common respiratory viruses.
The viruses detected were RSV (1913, 70.6%), parainfluenza viruses 1 - 3 (357, 13.2%), influenza A and B viruses (297, 11.0%), and adenovirus (141, 5.2%).
A cross-sectional study in Sarawak revealed that more than 30% of samples collected from children under one year of age were positive for RSV.
A recent study of the burden of RSV in adults reported that there were 7,416 RSV attributable hospitalisations in 2019 in Malaysia of which 60% were 65-year-olds and above.
The incidence of hospitalisations attributed to RSV increased with age, from 3.8 per 100,000 population in 20-49 year-olds to 294.3 per 100,000 population in 75-year-olds and above.
The estimated number of RSV attributable deaths was 704, of which, 63% were 65-years old and above.
The incidence of RSV attributable deaths increased with age from 0.4 per 100,000 population in 20-49-year-olds to 33.6 per 100,000 population in the 75 and above age group.
RSV is the leading cause of infant hospitalisation in the United States. — Filepic
Features and treatment
The clinical features of RSV infection include coughing, sneezing, fever, runny nose, wheezing, rapid breathing, feeding difficulty, restlessness, breathing difficulty and bluish skin or lips (cyanosis) in severe infections.
It is difficult to clinically differentiate RSV infection from influenza and the common cold because all these respiratory infections have similar symptoms of varying severity.
However, there are commercial tests of samples from the nasopharynx or trachea, which can provide an accurate diagnosis.
The risk of severe RSV infection is increased in infants and young children (the younger, the higher the risk); and children who are born prematurely, have chronic lung or congenital heart or neuromuscular disease; or have poor immunity.
The risk of severe RSV is increased in senior citizens above 75 years; those with chronic lung or heart disease, poor immunity, underlying medical conditions like diabetes and/or obesity; and residents in nursing homes.
Adult RSV can sometimes lead to a worsening of asthma, chronic obstructive airway disease and heart failure.
Supportive care is the mainstay of treatment as there is no specific treatment for RSV.
As RSV is a viral infection, antibiotics will not be of any use.
The treatment includes adequate hydration; clearance of nasal congestion or obstruction with saline nose drops, nasal bulb suction or suctioning in the hospital; and adequate nutrition with oral feeds encouraged.
Temporary feeding tubes (e.g. nasogastric) may be required in rare situations.
Oxygen may be needed in those unable to keep their oxygen saturation above 90% and mechanical ventilation considered if there is respiratory failure and/or severe apnoea.
Contact precautions and play or toy restrictions are necessary to decrease the spread of the infection.Leaving the respiratory syncytial virus (RSV) untreated can lead to serious health conditions.
Prevention methods
The Health Ministry has licensed an RSV vaccine for adults above 60 years and adults 50-59 years who are at increased risk of RSV lower respiratory tract disease.
Adult RSV can sometimes lead to a worsening of asthma, chronic obstructive airway disease and heart failure. — 123rf.com
However, an RSV vaccine for maternal and infant administration has yet to be licensed in Malaysia, although it has been licensed in many countries including United Kingdom, European Union, United States, Canada, Singapore, Hong Kong and Australia.
A 2024 local review of RSV vaccines for pregnant mothers concluded that, “Maternal immunisation with the RSVpreF vaccine effectively reduces the incidence of severe RSV-related LRTIs and hospitalisations in infants up to six months old. “The safety profile is favourable, supporting its use in maternal immunisation programmes globally.
“Further research should monitor the long-term outcomes and evaluate seasonal against universal administration for pregnant women.”
Children at increased risk of RSV are candidates for the monoclonal antibodies Nirsevimab and Palivizumab, both of which are administered intramuscularly.
The most significant constraint of these medicines is the high cost and the limited supply.
The shift in the prevention of infant RSV disease occurred with the availability of the RSV vaccine in 2023. This vaccine can be administered to mothers between 32 and 36 weeks of pregnancy, in addition to the monoclonal antibody which can be given directly to infants after birth.
The administration of vaccines to pregnant women stimulates their immune systems to produce antibodies which are then transferred to the foetus through the placenta.
At least 14 days are needed after maternal vaccination for sufficient antibodies to be produced to protect the baby after birth.
In some instances, babies born before 14 days after maternal vaccination may also receive the monoclonal antibody after birth, if cost is not an issue.
Regardless of maternal vaccination status, the recommendation in many developed countries is that infants born at below 34 weeks should receive the monoclonal antibody.
It is to be hoped that when the RSV vaccine is available for pregnant mothers in Malaysia, it would help turn the page on RSV with the potential to reduce the burden which is typically placed on babies.
Dr Milton Lum is a past president of the Federation of Private Medical Practitioners Associations and the Malaysian Medical Association. For more information, email starhealth@thestar.com.my. The views expressed do not represent that of organisations that the writer is associated with. The information provided is for educational and communication purposes only, and it should not be construed as personal medical advice. Information published in this article is not intended to replace, supplant or augment a consultation with a health professional regarding the reader’s own medical care. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.
