Respiratory syncytial virus hits older adults hard and is often missed. Learn symptoms, testing, and how new vaccines and pharmacists help prevent severe illness.
Respiratory syncytial virus (RSV) causes infections of the respiratory tract and the lungs and is the third-leading viral cause of hospitalization in adults older than 65 years, although it is often considered a pediatric disease. When RSV outbreaks emerged in long-term care facilities in the 1970s, the virus was recognized as a serious threat to older adults.1
It is estimated that RSV sends approximately 60,000 to 160,000 older Americans to the hospital each year and causes up to 10,000 deaths annually in adults 65 years and older, yet it remains underdiagnosed in adults.2 This may be due in part to the fact that its symptoms mimic other viral infections such as influenza and COVID-19. RSV testing is readily available yet not routinely performed. With 3 vaccines now approved for adults 60 years and older, pharmacists are a resource to help identify at-risk patients, guide vaccine selection, and close the critical prevention gap.3
Some practitioners might not fully grasp the impact of RSV on patient outcomes. A German analysis estimated that the actual hospitalization burden may be 8 to 14 times higher than what routine hospital records suggest because most hospitals do not routinely test adults for RSV, and because of the symptom overlap with other conditions.3 In industrialized countries, RSV incidence among older adults reaches over 600 cases per 100,000 person-years, with hospitalization rates of 157 per 100,000 persons.1 Hospital mortality ranges from 11% to 18%, comparable to influenza; however, patients with RSV experience longer hospital stays, at 6.0 days vs 3.6 days for patients with influenza.1 Although pneumonia is a risk for both groups, those with RSV are more likely to develop it (44% vs 28% for patients with influenza).1 Intensive care unit admission is required for 10% to 31% of hospitalized patients, and 3% to 17% require mechanical ventilation.1
The COVID-19 pandemic further disrupted RSV's predictable seasonal pattern. Widespread hygiene measures suppressed viral circulation, leaving the population unexposed to common viruses for an extended period. Once restrictions were lifted and people resumed normal activity, RSV and influenza returned simultaneously rather than following their usual seasonal patterns, a phenomenon now referred to as the "tripledemic."3
As patients age, their immune system gradually declines in function, a process known as immunosenescence. This means that older patients experience slower viral clearance, weaker immune responses, and a higher risk of progression to lower respiratory tract disease.1 Interestingly, older adults maintain antibody levels comparable to those of younger people, yet they still experience more severe disease, suggesting that the driver of severe RSV outcomes is not antibody quantity but dysfunctional T-cell responses.1 This same immune decline also explains why vaccine responses may be blunted in older adults, which directly informed the design of adjuvanted vaccines such as Arexvy (GSK). Several comorbidities further increase the risk of severe RSV disease in adults older than 60 years, including pulmonary conditions such as chronic obstructive pulmonary disease (COPD) and asthma, cardiovascular conditions such as congestive heart failure (CHF) and coronary artery disease, diabetes, severe obesity, chronic kidney disease (CKD, stages 4-5), and cancer.3
The most common symptoms associated with RSV are cough (85%-95%), shortness of breath (51%-93%), wheezing (33%-90%), rhinorrhea, fever, fatigue, and anorexia.1 Symptoms can range from mild upper respiratory infection to severe pneumonia and respiratory failure, particularly in high-risk older adults. When comparing RSV with influenza, RSV has a slower onset of 4 to 7 days, vs influenza's 2 to 3 days, with peak symptoms occurring at 7 to 13 days for RSV compared with 2 to 3 days for influenza.1 High fever and severe myalgia are more common with influenza, whereas cough and wheezing are more predominant with RSV.
Because symptoms between influenza and RSV overlap significantly, laboratory testing is required for a definitive diagnosis. The gold standard for RSV diagnosis is reverse transcriptase polymerase chain reaction testing on a nasal swab; rapid antigen tests are available but are less sensitive in adults.1 Pharmacists should encourage RSV testing alongside influenza and COVID-19 testing during respiratory season, especially in high-risk older adult patients.
Currently, there is no approved antiviral for RSV in adults. Management is supportive, including fluid administration, antipyretics, and supplemental oxygen as needed.1 Ribavirin (Rebetol; Merck) is the only FDA-approved antiviral for RSV, although its indication is limited to infants; off-label use in severely immunocompromised adults exists but is based on limited evidence.1 Several antivirals are in development, but none have been approved for adult use. This treatment gap is what makes RSV fundamentally different from influenza: vaccination remains the only evidence-based intervention available for older adults, making prevention that much more important.3
Some institutions are utilizing palivizumab as a means of RSV prophylactic therapy in high-risk infants.4 It has historically been administered on a fixed schedule with no regard to specific patient factors, but implementation of pharmacist-driven flex-schedule administration has promoted better patient outcomes.4 Although this therapy is not used in older adults, it shows the impact that pharmacists make by providing expertise on patient-specific dosing and administration schedules. This same unique knowledge can be used to individualize vaccine scheduling in older adults and help distinguish when patients may be at higher risk.
All 3 approved RSV vaccines (Arexvy from GSK, Abrysvo from Pfizer, and Mresvia from Moderna) work by targeting the prefusion F protein, the form of RSV's fusion protein that generates the strongest neutralizing antibody response. Arexvy and Abrysvo were approved by the FDA in May 2023, and mRESVIA received FDA approval in May 2024.3 Because each vaccine was evaluated using different trial designs, populations, and seasons, direct comparisons between them are not appropriate. Each of the 3 vaccines is effective, but the choice depends on individual patient factors and availability.3 Arexvy contains an adjuvant, an ingredient that helps create a stronger immune response, which is particularly relevant for the oldest or frailest patients whose immune systems may respond less robustly to vaccination alone.1 Both Arexvy and Abrysvo demonstrated efficacy through 2 RSV seasons, and data suggest that a single dose is as effective as annual revaccination.1 mRESVIA is available as a prefilled syringe, which requires less preparation time and reduces the potential for administration errors.3 Notably, Abrysvo is the only vaccine of the 3 approved for use during pregnancy at 24 to 36 weeks’ gestation, providing passive protection to newborns.3 No single vaccine is superior; the optimal choice depends on individual patient factors and availability.
The CDC's 2024 updated recommendations advise that all adults aged 75 and older receive a single dose of any approved RSV vaccine.2 For adults aged 60 to 74 years, vaccination is recommended for those with chronic conditions such as COPD, CHF, CKD, diabetes, or obesity, as well as those residing in nursing homes or long-term care facilities.2 Previously vaccinated patients should not receive another dose, as a single dose provides protection for at least 2 RSV seasons. Vaccination should ideally be administered in late summer or early fall, before the RSV season begins.2 For adults aged 60 to 74 years, the CDC employs a shared decision-making (SDM) framework, meaning vaccination is not an automatic recommendation, but rather requires an informed conversation between the patient and their provider.2
Amber Gilliam and Lynn Medal are PharmD candidates at the Touro University California College of Pharmacy.
Shane Desselle, RPh, PhD, is a professor of social and behavioral pharmacy at the Touro University California College of Pharmacy.
A recent study showed that 78% percent of patients receiving RSV vaccination education at a community pharmacy had not received any RSV education from their primary care provider.5 Along with lack of RSV education, patients often have hesitancy toward vaccines due to risk of adverse effects and misunderstanding of vaccine importance as prophylactic therapy.5 This is one area in which pharmacists can play an important role. An SDM discussion should cover a patient's risk factors, available vaccine options, expected benefits, potential adverse effects, and the opportunity to coadminister the RSV vaccine alongside the seasonal influenza vaccine.3 Patients in community pharmacy settings were observed to be more likely to receive an RSV vaccine after consulting with the pharmacist.4
RSV may have long been considered a pediatric disease, but with 3 vaccines now approved and pharmacists at the forefront of patient education, that narrative is finally changing. Pharmacists have significant opportunities to improve therapies for older adults affected by the condition.
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