Children’s hospitals nationwide faced an extraordinary influx of young patients grappling with respiratory syncytial virus (RSV) last autumn. As early as October, the surge reached a point where several states declared emergencies, prompting makeshift outdoor care spaces with additional beds in hospital parking lots.
Anticipations for this year’s RSV season lean towards a return to pre-pandemic scheduling. However, the projected case figures could diverge significantly. This outcome hinges on how individuals adopt novel preventive measures against RSV.
How can a cold-like illness cause such severe symptoms?
US Centers for Disease Control and Prevention report that nearly everyone gets RSV by age 2. Typically mirrors cold symptoms: runny noses, coughing, sneezing, and sometimes fever. While usually mild, RSV’s course can be uncertain. A recent study revealed that many children in the ICU during RSV last year were healthy and full-term births.
The vulnerability of young infants and the elderly to severe RSV infection is notable. Dehydration and respiratory issues can arise, escalating to pneumonia and bronchiolitis. Regarding hospitalization in infants’ first year, RSV ranks as the top cause.
Yearly, RSV results in hospitalizations for around 80,000 children under 5 and approximately 160,000 individuals aged 65 and above. CDC estimates suggest it claims 100 to 300 young lives and impacts 6,000 to 10,000 older adults annually.”
Inconsistent virus seasons
As highlighted by the CDC, RSV, a disease with a seasonal pattern, traditionally impacts the US from October to April, with the peak surge occurring in December or January. However, the course of events was altered by the Covid-19 pandemic.
The 2020-21 RSV season witnessed an exceptionally low incidence of cases. The virus spreads through coughs, sneezes, and contaminated surfaces, like doorknobs and elevator buttons. Measures such as lockdowns, masks, and frequent handwashing, implemented to combat Covid-19, played a role in keeping RSV at bay.
The pandemic-driven decline in RSV cases resulted in what some experts call an “immunity gap.” The subsequent season, 2021-22, observed a return to near-pre-pandemic case levels, with the virus gaining momentum around May—approximately 21 weeks ahead of its typical timeline. The season reached its peak in July and concluded prematurely in January.
In 2022-23, the RSV season commenced a bit earlier than usual, in June, but made a formidable comeback. Children, who might have developed immunity during the pandemic years, found themselves vulnerable, leading to a surge in hospitalizations starting in November.
The impact wasn’t confined to children alone. Older adults also faced heightened hospitalization rates. By November 2022, the CDC reported a tenfold increase in RSV hospitalizations for individuals aged 65 and older compared to the norm.
Typical timing expected
According to Dr. Daniel Weinberger, an associate professor specializing in epidemiology of microbial diseases at the Yale School of Public Health, the US can expect a return to regular timing this year. “It appears that RSV will follow its typical seasonal pattern, which has been uncertain in recent years,” he remarked.
Like monitoring the flu, researchers track the Southern hemisphere to gain insights into the upcoming season’s trajectory. With winter ongoing in that region and the RSV season winding down, it offers some indication of the US scenario, albeit not always precise.
Dr. Weinberger observed that this year’s RSV season started nearly on par with its pre-pandemic schedule, possibly slightly ahead in certain nations. Given the considerable number of RSV cases in the US last year, he anticipates this season’s intensity to approach a “normal” level, more aligned with pre-Covid figures.
Dr. Claudia Hoyen, overseeing pediatric infection control at UH Rainbow Babies and Children’s Hospital in Cleveland, highlighted a contrast between this summer and the previous one. While RSV cases were already surfacing by this point last year, the past three months have been unusually subdued.
Dr. Hoyen receives daily reports on positive cases and noted that the recent period has been marked by an “eerie quietness.” The absence of such patterns in recent years has been unsettling for pediatricians accustomed to disease seasons. Dr. Hoyen expressed a cautious hope that this calmness isn’t a precursor to an impending surge.
Vaccines and antibodies are now available!
As the RSV season approaches, experts are optimistic about improved outcomes, thanks to a newly approved monoclonal antibody designed to safeguard infants from RSV. Anticipating seasonal infection waves is crucial for timely proactive measures, such as therapies and vaccines. This year, noteworthy developments include vaccines for older adults and preventive options for infants, enhancing the efficacy of these interventions.
For over two decades, a single monoclonal antibody has protected high-risk infants from RSV. Administered once monthly during the RSV season, this treatment has been highly effective. However, a significant breakthrough arrived as nirsevimab, marketed as Beyfortus, gained FDA approval in July. Children at high risk and infants up to 8 months of age, who were born during or entering their first RSV season, are currently covered by this long-acting monoclonal antibody recommended by the Centers for Disease Control and Prevention. Trials demonstrated an approximately 80% reduction in RSV-related hospitalizations and doctor visits.
Additionally, two RSV vaccines are available for those aged 60 and older. These single-dose vaccines, endorsed by the CDC in June, are projected to offer protection across multiple seasons, akin to the flu shot schedule. The potential impact of these interventions is substantial, with experts asserting their potential to significantly curtail RSV’s impact.
Reflecting on the introduction of monoclonal antibody treatments in the ’90s, healthcare professionals highlight their transformative impact on vulnerable infants. Before their availability, RSV seasons were fraught with apprehension as lives hung in the balance. Today, these treatments stand as lifesaving measures, promising to save numerous lives.
While the adoption of these protective measures remains uncertain, experts anticipate more openness toward monoclonal antibody treatments compared to vaccines like Covid-19. The American Academy of Pediatrics urges equitable access to these therapies, recognizing the need for a comprehensive strategy. Growing awareness of RSV’s dangers, amplified by last year’s overwhelming hospital scenes, may drive increased willingness to seek protection.
The convergence of new tools and increased awareness provides hope for a more manageable RSV season. By embracing interventions such as monoclonal antibodies and vaccines, individuals can actively contribute to safeguarding infants and older adults against this challenging respiratory virus.
