Pfizer’s RSV vaccine ABRYSVO just became the first licensed option for at-risk adults as young as 18, closing a long-standing protection gap for younger people living with chronic conditions. About one in ten U.S. adults aged 18 to 49 has a condition like diabetes, asthma, or heart failure that raises their risk of severe RSV illness — and until now, they had nothing. The vaccine targets RSV’s prefusion F protein, a breakthrough that finally unlocked effective design after decades of frustrating research. With approvals now spanning pregnant individuals, older adults, and at-risk younger adults, ABRYSVO marks a quiet but powerful turning point in a field that struggled for half a century — a reminder that patient science eventually delivers real protection to real people.