Burden and vaccines in older adults and chronic disease

Respiratory syncytial virus causes clinically important lower respiratory tract disease among older adults and those with multimorbidity, with outcomes ranging from medically attended acute respiratory illness to hospitalization and death. The burden is concentrated in individuals with chronic lung and heart disease, metabolic disorders, renal impairment, and frailty. In these populations, RSV is a trigger for decompensation of underlying conditions, including COPD exacerbations, acute heart failure, and bacterial superinfection. The evidence base now supports primary prevention using vaccines to reduce the incidence and severity of respiratory syncytial virus infections, complementing nonpharmacologic measures and clinical vigilance.

Disease burden and risk stratification

Risk is not uniform across older adults. Those living with chronic obstructive pulmonary disease, chronic asthma, or interstitial lung disease face higher rates of RSV-associated lower respiratory tract disease and hospitalization. Cardiovascular comorbidities such as heart failure and coronary artery disease are associated with worse outcomes, including acute decompensation during viral illness. Metabolic and renal conditions, notably diabetes mellitus type 2 and chronic kidney disease, add to risk through impaired immune responses and frequent healthcare contact. Residence in long-term care, high comorbidity counts, and frailty further compound the likelihood of severe disease and functional decline after infection.

Vaccine platforms and effectiveness

Licensed RSV vaccines for older adults use distinct antigen designs and adjuvant strategies to elicit robust neutralizing responses against the prefusion F protein, the target of protective antibodies. Across pivotal trials, primary endpoints focused on prevention of virologically confirmed RSV lower respiratory tract disease in adults aged 60 years and older. Although efficacy point estimates vary by platform and season, results consistently demonstrate clinically meaningful vaccine effectiveness against medically attended disease, with sustained but somewhat attenuated protection across subsequent seasons. Safety profiles are acceptable in older populations, with reactogenicity typically mild to moderate and transient; rare serious adverse events require ongoing post-authorization monitoring.

Seasonality and timing in Portugal

Portugal experiences a temperate Northern Hemisphere pattern of RSV circulation, with annual peaks in colder months. Vaccination programs should align with expected seasonal onset to maximize protection during the period of highest exposure. Pre-season administration allows sufficient time for immune responses to mature, while flexible scheduling accommodates logistics in primary care, specialty clinics, pharmacies, and long-term care facilities. Coordination with other respiratory vaccine campaigns can improve uptake and streamline workflows without compromising safety when appropriate coadministration rules are followed.

Eligibility, prioritization, and timing

The societies endorse offering RSV vaccine to older adults and to adults with specified chronic disorders who are at elevated risk of complications. In practice, patient selection should reflect overall risk rather than age alone, accounting for the nature and control of comorbid conditions and the setting of care. The approach below supports consistent decision-making in primary and specialty care while enabling clinicians to individualize recommendations. When supply is constrained, transparent prioritization helps focus limited doses where the absolute benefit is greatest.

Who should be offered RSV vaccine

Eligible populations include older adults and persons with chronic medical conditions that predispose to severe RSV outcomes. Offer vaccination to adults aged 60 years and older, and consider vaccination for selected adults under 60 with high-risk profiles after shared decision-making. High-risk conditions include chronic lung disease such as COPD, moderate to severe asthma, bronchiectasis, and interstitial lung disease; cardiovascular disease including heart failure, coronary disease, and significant valvular disease; metabolic disease such as diabetes; chronic kidney or liver disease; neurologic disorders affecting cough or airway clearance; and states of immunosuppression. Residents of long-term care and individuals with marked frailty are priority groups given increased exposure risk and potential for rapid deterioration.

Prioritization tiers during limited supply

When vaccine supply or appointment capacity is limited, apply a tiered approach to sequence access. First prioritize adults with the highest risk of severe outcomes: older adults with multiple comorbidities, particularly those with advanced cardiopulmonary disease, insulin-requiring diabetes, or progressive renal impairment, and residents of long-term care. Next, vaccinate other adults aged 60 years and older and those aged under 60 with a single high-risk condition or multiple moderate-risk conditions. Finally, offer vaccination to remaining eligible adults based on clinical judgment, exposure risk, and patient preference. Revisit prioritization as supply improves and as local epidemiology evolves.

Timing relative to the RSV season

Administer vaccination ahead of anticipated seasonal RSV circulation to ensure protection during peak months. If patients present after seasonal onset, vaccinate at the earliest opportunity, since meaningful exposure risk persists throughout the RSV period. Incorporate RSV vaccination into established pre-winter visit workflows, including chronic disease reviews, device checks for cardiopulmonary patients, and wellness visits, to improve uptake. For long-term care facilities, schedule on-site vaccination drives before the season and maintain rolling catch-up clinics for new admissions and recently discharged hospital patients.

Coadministration with other vaccines

RSV vaccines may be coadministered with other adult vaccines commonly indicated in the same populations when clinically appropriate. Pragmatically, coadministration with influenza vaccine during pre-season visits can increase coverage for both pathogens. Coadministration with pneumococcal vaccines is also reasonable, particularly for patients at risk of pneumonia, provided injections are given at separate anatomical sites. Clinicians should counsel patients about the possibility of increased local or systemic reactogenicity with multiple vaccines on the same day, emphasize that such reactions are typically self-limited, and provide advice on symptom management and return precautions.

Safety, coadministration, and implementation

Vaccine safety, clear documentation, and robust pharmacovigilance are central to sustained public and professional confidence. Standardized workflows that integrate eligibility checks, shared decision-making, informed consent, and electronic health record documentation can reduce missed opportunities. Where applicable, coding and reimbursement should reflect national policies to support equitable access across care settings. Finally, communication strategies tailored to older adults and those with chronic disease can increase acceptance while avoiding oversimplification of benefits and risks.

Contraindications and precautions

RSV vaccination is contraindicated in individuals with a history of severe allergic reaction to a previous dose or to known vaccine components. Defer vaccination in patients with acute severe illness until recovery. Exercise caution in individuals with unstable or decompensated chronic disease; vaccinate once the condition is reasonably controlled to minimize confounding of post-vaccination symptoms and to maximize benefit. For patients with known bleeding disorders or on anticoagulation, use standard intramuscular injection precautions and apply pressure to the site to reduce bruising risk.

Adverse events and pharmacovigilance

Most adverse events after RSV vaccination are local and systemic reactogenicity, such as injection-site pain, fatigue, myalgias, or low-grade fever, typically resolving within a few days. Serious adverse events are rare and require prompt clinical evaluation and national reporting according to pharmacovigilance rules. Provide clear return instructions for persistent or severe symptoms, and ensure clinicians and pharmacists know how to submit timely reports. Aggregate safety monitoring at the national level is essential to contextualize signals, differentiate coincidental events in older multimorbid adults from causal associations, and update guidance when needed.

Documentation, coding, and reimbursement

Record the vaccine product, lot number, administration site, and date in the electronic health record at the time of vaccination. Include indication details such as age eligibility or qualifying comorbidities to support audit and quality improvement. Use appropriate coding to facilitate reimbursement in primary care, hospital outpatient departments, and long-term care facilities, in accordance with national policy. Document shared decision-making for adults under 60 years with high-risk conditions, including a brief rationale for vaccination.

Communication and shared decision-making

Discuss RSV risk, expected vaccine benefits, and common side effects using clear, balanced language tailored to the patient’s health literacy. For individuals with multiple comorbidities or concerns about polypharmacy and polyvaccination, acknowledge uncertainty where it exists and emphasize ongoing safety monitoring and the reversible nature of most side effects. When multiple vaccines are due, present options for coadministration versus spaced visits, respecting patient preferences and logistical constraints. Engage caregivers in decision-making for residents of long-term care and for older adults who rely on family support to access services.

Integration with chronic disease care

Embed RSV vaccination into chronic care pathways to reduce missed opportunities. For pulmonology clinics, pair vaccination with routine assessments for COPD or bronchiectasis, pulmonary rehabilitation touchpoints, and oxygen or ventilatory support follow-ups. Cardiology and general medicine clinics can incorporate reminders during heart failure optimization visits, device checks, and anticoagulation reviews. Primary care teams should include RSV vaccination in pre-winter chronic disease reviews, leveraging registries to identify eligible patients and aligning outreach with influenza and pneumococcal vaccination campaigns.

Long-term care and transitions

Long-term care facilities should implement standing orders and on-site clinics to increase vaccination rates among residents and staff. For patients transitioning from hospital to home or to rehabilitation, include RSV vaccination in discharge planning when feasible, or schedule prompt follow-up in primary care. Coordinated communication between hospitalists, specialists, and community providers prevents duplication, ensures the vaccine status is updated across records, and supports timely catch-up for those who missed pre-season opportunities. Monitoring uptake and outcomes at the facility level can guide targeted quality improvement.

Equity, access, and outreach

Equitable access requires proactive identification of at-risk patients who may face barriers such as transportation, limited clinic hours, or low digital literacy. Community pharmacies, mobile clinics, and outreach in social care settings can extend reach beyond traditional clinic walls. Culturally sensitive communication and language-access services are critical for diverse older populations. Tracking coverage by age, comorbidity groups, and geographic region helps identify gaps and prioritize interventions ahead of each season.

Evidence updates and uncertainties

Key outstanding questions include the durability of protection over multiple seasons, the optimal timing for potential revaccination, and the degree of effectiveness in highly frail or immunocompromised individuals. As real-world data accumulate, efficacy estimates may vary by age, comorbidity burden, and healthcare setting, necessitating periodic updates to guidance. Safety surveillance will clarify rare risks and inform any product-specific precautions. Clinicians should monitor national advisories and society statements for revisions aligned with emerging evidence.

In synthesis, RSV vaccination offers a meaningful opportunity to reduce severe respiratory disease and downstream decompensation in older adults and persons with chronic disorders. A standards-based approach that prioritizes the highest-risk individuals, aligns timing with seasonal circulation, and enables safe coadministration can be implemented across Portugal’s healthcare settings. Practical elements such as clear documentation, consistent pharmacovigilance, and equitable outreach are essential for sustained impact. Ongoing evidence synthesis and transparent communication will ensure that these recommendations remain current, effective, and responsive to patient needs.