Respiratory Syncytial Virus (RSV) is a common respiratory virus that can cause mild to severe illness, particularly in infants, young children, older adults, and individuals with weakened immune systems. While often overlooked, RSV can lead to serious complications such as pneumonia and bronchiolitis, especially in infants.
In recent years, significant strides have been made in combating RSV. One of the most promising developments is the introduction of a new vaccine, Abrysvo, designed to protect vulnerable populations from this pervasive virus. This blog post will delve into the intricacies of RSV, explore traditional treatment options, and highlight the potential impact of Abrysvo on the health of mothers and their children.
Table of Contents
What is RSV?
You’ve probably heard of RSV, even if you don’t know it by name. Almost every child under the age of 3 has been exposed to it. While it often causes mild cold-like symptoms, it can be a real threat, especially for babies, the elderly, and people with weakened immune systems.
While most people recover from RSV without complications, it can be particularly dangerous for infants, older adults, and individuals with weakened immune systems. RSV typically causes cold-like symptoms such as runny nose, cough, and fever. However, in severe cases, it can lead to more serious respiratory illnesses like pneumonia and bronchiolitis.
Who’s Most at Risk?
- Infants: Premature babies, those with heart conditions, lung problems, Down syndrome, or neuromuscular disorders are particularly vulnerable.
- The Elderly: Older adults are also at risk for severe RSV infections.
In many countries, RSV is a major cause of infant mortality. Even in places with better healthcare, it can lead to serious hospitalizations and long-term health issues like asthma.
In Singapore, RSV is a significant burden on the healthcare system.From 2011 to 2016, 42% of viral respiratory tract infections in paediatric hospitalisations in Singapore KKH are from RSV. It’s one of the leading causes of respiratory infections in children, resulting in countless hospitalizations and millions of dollars in healthcare costs. For example, the total cost of RSV hospitalization and primary care consultations in Singapore reached SGD6,228,000 in 2014.
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Overview of the Abrysvo RSV Vaccine
Abrysvo is the only approved RSV maternal vaccine, since it was FDA approved in August 2023. While other treatments for RSV may only be administered to the non-pregnant segment of the population, Abrysvo is the only one that can be taken by pregnant women. It is meant to be administered between 32 and 36 weeks of pregnancy in a single intramuscular dose. It is also available for use by patients aged 60 years or older, or patients 18-59 years old who are at increased risk for RSV-related lower respiratory tract disease (LRTD).
Abrysvo is composed of two RSV proteins that work to stimulate the immune system to produce antibodies against the virus. It has been shown to be effective in preventing RSV-LRTD in adults 60 years and older and in infants born to vaccinated mothers. The main benefit is the immediate protection from birth via transplacental transfer of antibodies against severe RSV-LRTD. There is a 91% vaccine efficacy for infants under 3 months and 76% vaccine efficacy in infants under 6 months. The disadvantages are the possible potential lower production or transfer of antibodies eg in immunocompromised pregnant patients or deliveries less than 2 weeks from time of vaccine administration.
How does maternal Abrysvo vaccination compare to other RSV treatments given to infants? For example, an antibody Palivizumab provides passive immunity to RSV. It was licensed by the FDA in 1998 and is currently recommended for use for prematurity (before 29 weeks) and is administered for a maximum of five monthly doses in the first year of life. It has been shown that its effectiveness against RSV hospitalisation at 6m post-discharge was 90%. The downside is that it is costly – the crude cost to prevent 1 RSV hospitalisation with palivizumab in a tropical setting is around SDG22,400.
What about the antiviral ribavirin? This antiviral drug inhibits replication of both RNA and DNA viruses and is administered by IV, PO, and aerosolization. It is FDA-approved as a treatment for RSV. However, it is expensive, there are concerns for potential teratogenicity of inhaled particles, and evidence is lacking as to routine use of ribavirin in infants with severe RSV.
The monoclonal antibody Nirsevimab is also a form of passive immunization. It locks RSV F Protein in a pre-fusion conformation to block the virus’ entry into host cells. Its efficacy is at 74.5% for medically-attended RSV-associated lower respiratory tract infection. A single dose of Nirsevimab protects against RSV for at least five months. There is potentially longer protection of antibodies as it is directly administered instead of via transplacental transfer of antibodies but requires infant injection and limited quantities of availability may affect its usage.
Abrysvo Vaccine During Pregnancy
Abrysvo is approved for use in pregnant individuals between 32 and 36 weeks of gestation to protect their infants from RSV infection from birth through 6 months of age.
The vaccine protects infants from severe RSV infection, which can lead to hospitalisation. It also reduces the risk of RSV-related complications in infants.
It is generally safe, with the common side effects including pain at the injection site, headache, muscle pain, and nausea. Serious side effects are rare. In one study, there was a slight incidence of borderline preterm birth in the vaccinated group (4.2% versus 3.7%) but this was not statistically significant and mostly occurred at 36 weeks gestation.
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Approval and Availability in Singapore
The Health Sciences Authority (HSA) in Singapore is responsible for regulating health products, including vaccines. They assess the safety, quality, and efficacy of new vaccines through a rigorous review process. This process involves review of clinical trial data, evaluation of manufacturing processes, and assessment of the risk-benefit profile.
Abrysvo has been approved in Singapore by the HSA since July 2024 and is currently available in medical facilities in Singapore. It is estimated to cost SGD350 for a single dose.
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Conclusion
The arrival of Abrysvo marks a significant milestone in maternal and infant health. By vaccinating pregnant women, we can provide crucial protection to their newborns during their most vulnerable months. This groundbreaking vaccine offers hope for a future where RSV-related illnesses are a thing of the past. As we continue to advance in medical science, let’s embrace this opportunity to safeguard the health of our little ones.
Pregnant women are encouraged to consult with their healthcare providers to learn more about the benefits of the Abrysvo vaccine and to determine if it’s right for them. To schedule an appointment, please call +65 9039 1000 or send us a message.
Please note that this blog post is intended for informational purposes only and should not be considered as a substitute for professional medical advice. Always consult with a qualified healthcare provider for any health concerns.
SOURCES:
Dr Pamela Tan is a board certified obstetrician and gynecologist in Singapore. She finished her undergraduate studies at the National University of Singapore and earned her post-graduate degree at the Royal College of Obstetricians and Gynaecologists in the UK. She is an accredited specialist by the Specialist Accreditation Board (Ministry of Health), and a fellow of the Academy of Medicine, Singapore. She subspecialises in colposcopy and is certified to perform Level 3 minimally invasive keyhole surgeries such as laparoscopic hysterectomy, myomectomy and cystectomy. Dr Pam also supports the natural birthing method and she strives to provide a personalised care and treatment for each patient.