Every year, the spectre of Respiratory Syncytial Virus (RSV) haunts the corridors of Malaysian hospitals.
For parents, it is the agony of watching their infant struggle to breathe. For paediatricians, it is the annual surge of overcrowded emergency departments (ED) and strained ICU beds.
For too long, we have treated RSV as an inevitable rite of passage for winter, or, in our tropical climate, a perennial threat.
RSV-induced bronchiolitis is the leading cause of hospitalisation among infants due to lower respiratory tract infections (LRTI).
Globally, RSV drives more than 30 million LRTI annually in children under five years old, resulting in 3.2 million hospitalizations and 200,000 deaths each year.
In Malaysia, eight out of 10 RSV hospitalisations occur in healthy term infants, with 85 per cent of severe RSV disease occurring in otherwise healthy children.
However, a monumental shift is occurring in pediatric medicine. The arrival of nirsevimab, a long-acting monoclonal antibody, promises to rewrite the narrative of RSV prevention.
But, as we consider introducing nirsevimab into Malaysia’s health care arsenal, we must look past the hype and interrogate the data. Does it truly deliver?
A comprehensive meta-analysis of 37 studies, recently reviewed in the literature, provides a definitive answer: yes, but with nuance.
The Shield Is Strong
The numbers are nothing short of impressive. When it comes to keeping babies out of the ED, nirsevimab demonstrates a pooled effectiveness of 80.7 per cent.
The protection against hospital admissions mirrors this, standing at another robust 80.7 per cent.
For Malaysian parents, these figures represent a chance to avoid the trauma of watching their child hooked up to oxygen or a respirator.
For our health care system, it means decongesting wards that are typically overrun during peak RSV seasons.
Even in primary care settings, studies like that of Lopez-Lacort show an effectiveness of 75.8 per cent in infants under 10 months old—proving that this protection begins at the community level.
However, a closer look reveals a “time is of the essence” component. Barbas Del Buey et al. found that effectiveness against RSV hospitalisation is highest in the first month of life (93.6 per cent at 30 days), declining slightly to 87.6 per cent at five months.
In addition, one key issue in Malaysia is year-round RSV circulation, which requires persistent protection beyond six months.
A follow-up study with results up to 18 months from Spain demonstrated an 80.4 per cent persistent reduction in hospitalizations with no signal of an adverse shift in RSV morbidity in later age.
We must aim to immunise infants before they encounter the virus, ideally in the neonatal period, administered prior to hospital discharge.
Beyond RSV: A Broader Impact
Perhaps the most intriguing data point is the spillover effect. While nirsevimab is targeted at RSV, it also showed a pooled effectiveness of 54 per cent against all-cause LRTI hospital admissions.
Furthermore, it managed to reduce LRTI-related ICU admissions by a staggering 68.1 per cent.
Why does this matter? In Malaysia, where we often lack the rapid PCR testing capacity to distinguish RSV from other pathogens immediately, this broad protective effect is a godsend.
It suggests that even if the virus is not definitively identified, the drug is actively reducing the severity of respiratory illness overall.
A landmark French study also found that RSV-immunised infants were 34 per cent less likely to be hospitalised for invasive pneumococcal disease (IPD) compared to non-immunised babies up to nine months of age.
The Real-World Impact
Eleven studies reported a reduction in RSV-related primary care visits, hospital admissions, ED visits, or ICU admissions in the 2023/2024 season, compared with previous seasons.
One study found that the incidence rates of RSV-related hospitalisations were similar (due to low uptake of nirsevimab).
Safety: The Bedrock Of Trust
For parents and paediatricians, safety is paramount. The pooled real world safety data for nirsevimab is overwhelmingly reassuring.
Eight studies reported mild transient symptoms and no severe adverse effects. In an Australian study of 410 parents, 88.5 per cent reported no adverse effects. The most common complaints were fatigue (7.1 per cent), local reactions (2.3 per cent), and mild fever (3.4 per cent).
The Malaysian Conundrum
So, the data is clear: this is a highly effective, safe intervention that relieves pressure on health systems. Why then, does hesitation linger?
Cost remains the elephant in the room. Unlike vaccines that cost a few Ringgit, monoclonal antibodies are expensive.
However, we must ask ourselves: what is the cost of one night in a Malaysian paediatric ICU (PICU)? What is the economic burden on a parent who must take a month of unpaid leave to care for a hospitalised child?
The debate should not be “Can we afford it?”, but rather “Can we afford not to invest in a generation of healthier children?”
The Way Forward
The evidence base for nirsevimab is no longer nascent; it is robust. For Malaysia, the path forward requires strategic planning.
We must identify the most vulnerable cohorts — perhaps premature infants, those with congenital heart disease or chronic lung disease — for immediate coverage, while working towards a national programme.
We also need to push for local pharmacoeconomic studies to prove that the high cost is offset by the savings in hospital care and parental productivity.
The data says we can protect our children. Now, we must find the will to do it, to give Malaysian children the healthiest possible start in life.
Dr Musa Mohd Nordin is a consultant paediatrician at Damansara Specialist Hospital, and Dr Husna Musa is a consultant paediatric neurologist at Universiti Putra Malaysia.
- This is the personal opinion of the writer or publication and does not necessarily represent the views of CodeBlue.
