RSウイルス（呼吸器合胞体ウイルス）ワクチン

乳幼児、高齢者、免疫不全者、妊婦（新生児への受動免疫のため）。

Severe allergic reaction to previous dose or any component. Moderate to severe acute illness (defer). Abrysvo maternal use: avoid if preterm delivery risk is high (limited data in preterm). mRESVIA: PEG/polysorbate allergy caution (mRNA-LNP platform).

Arexvy — Very common: injection site pain (61%), fatigue (34%), myalgia (29%), headache (27%). Common: arthralgia, fever. Abrysvo — Very common: injection site pain (41% adults), fatigue (21%), headache (18%). Maternal: injection site pain (41%), headache (31%), myalgia (27%). mRESVIA — Very common: injection site pain (59%), fatigue (38%), headache (30%), myalgia (32%), arthralgia (22%). GBS signal: FDA monitoring for Arexvy/Abrysvo — no confirmed causal association; ACIP notes shared clinical decision-making partly due to this signal.

Adults ≥60 years: single 0.5 mL dose IM (deltoid). No booster currently recommended (under study). Maternal immunization (Abrysvo): single 0.5 mL dose IM at 32–36 weeks gestation during RSV season. mRESVIA: single 0.5 mL dose IM. Administer before RSV season onset (September–October in Northern Hemisphere).

Arexvy: 82.6% efficacy (95% CI 57.9–94.1%) against RSV-associated lower respiratory tract disease (LRTD) in ≥60y, season 1. Abrysvo (adults): 66.7% against RSV-LRTD with ≥2 symptoms. Abrysvo (maternal): 81.8% efficacy against severe RSV-LRTD in infants within first 90 days. mRESVIA: 83.7% efficacy against RSV-LRTD (≥2 symptoms) in ≥60y. Second-season data shows waning for all products.

Arexvy/Abrysvo: +2°C to +8°C. mRESVIA: -25°C to -15°C (frozen), thawed at +2°C to +8°C for up to 30 days. All: protect from light, do not freeze (Arexvy/Abrysvo).

Can be co-administered with seasonal influenza vaccine (no interference). Can be co-administered with COVID-19 mRNA vaccines (limited data, acceptable). Co-administration with other adult vaccines (Tdap, pneumococcal, shingles): limited data but expected to be safe (non-live vaccines). No known drug interactions.

Abrysvo: approved for maternal immunization at 32–36 weeks gestation. No teratogenicity in animal studies. FDA post-marketing surveillance ongoing for preterm birth signal (not confirmed but noted). Arexvy/mRESVIA: not indicated in pregnancy. Breastfeeding: expected safe for all products (non-live).

NOT approved for infants or children. Infant protection achieved via maternal Abrysvo vaccination OR nirsevimab (beyfortus) monoclonal antibody passive immunization.

Primary target population. Adults ≥60 years at highest risk of RSV-associated LRTD. Consider chronic cardiopulmonary conditions, diabetes, immunocompromised status as additional risk factors. Co-decision with patient given GBS signal.

Guillain-Barré syndrome (GBS): surveillance signal noted for Arexvy and Abrysvo in post-marketing data — contributes to shared clinical decision-making recommendation rather than universal recommendation. Maternal Abrysvo: seasonal timing important — benefit limited outside RSV season. Do not confuse with nirsevimab (monoclonal antibody for infants) — different product class. Single-season recommendation in Year 1; whether to repeat annually under study.