文章（2026年1月1日 5:30 AM）重点在以「降低机率＋降低重症」来度过感冒与流感季。对季节性流感，CDC 指出每年接种疫苗是降低风险与严重并发症的单一最佳方法；北美通常在9–10月有新一年度疫苗，但错过也不晚，因为流感季一般从10月持续到4月底，且多在1–2月达到活动高峰。

疫苗不会「打出流感」：针剂多用不活化（死亡）病毒或仅含单一蛋白；鼻喷型含减毒活病毒，适用年龄为2–49岁。接种后要到最多约2周才达到完整保护，因此若在接种前后2周内暴露仍可能生病，但原因是暴露而非疫苗本身。

疫苗效果会随年度株系而变，但能显著降低重症；例：2024–2025季的疫苗有效性为56%，为近约15年来较高水准。文中以「50%有效性」作直观说明：接种者在该季需要就医的风险约为未接种者的一半。除疫苗外，建议用分层措施降低传播：勤洗手、少摸脸、避开病人、必要时戴口罩、病时在家、用手肘内侧咳嗽/打喷嚏、清洁高接触表面；空气清净机在真实世界降低感染的证据目前不明确，只能作为辅助。

Dated Jan 1, 2026, the piece emphasizes reducing both infection probability and severity during cold/flu season. For seasonal flu, the CDC calls annual vaccination the single best risk-reduction step. The ideal window is September–October in North America, but vaccination still matters later because the season typically runs from October through late April, with the most activity often in January–February.

It stresses that flu vaccines cannot give you flu: injected vaccines use inactivated virus or a single viral protein. The nasal-spray vaccine contains live attenuated virus and is for ages 2–49. Protection is not immediate; it can take up to 2 weeks to reach full effect, so illness after exposure shortly before or within those 2 weeks can occur, but it is not caused by the shot.

Effectiveness varies by year and strain but strongly reduces severe outcomes. In 2024–2025, vaccine effectiveness was 56%, the highest in nearly 15 years. A 50% effectiveness example means vaccinated people had about half the risk of needing medical care for flu versus unvaccinated people that season. The article recommends layered controls—handwashing, avoiding sick contacts, masking when appropriate, staying home when ill, elbow coughing, and cleaning high-touch surfaces—while noting real-world evidence for air purifiers reducing infections remains unclear.