根據美國疾病控制與預防中心（CDC）的數據，截至目前，全美累計報告約290萬例流感病例，其中住院人數約3萬，死亡病例達1200例。此次流感疫情以甲型H3N2病毒為主要流行毒株，全美流感活動仍在持續上升。

具體數據顯示，截至12月6日當周，美國公共衛生實驗室檢測的547份流感病毒樣本中，96%為甲型流感，其中H3N2亞型占主導；乙型流感僅占4%。值得注意的是，12月第一周報告了本季首例兒童流感死亡病例，這一消息引起社會對高危人群的高度關注。CDC已分發1.27億劑流感疫苗，並建議6個月及以上的人群盡快接種，同時強調抗病毒藥物對老年人和慢性病患者的重要性，以降低重症和死亡風險。

儘管疫苗已廣泛分發，美國流感疫情仍然嚴重，原因主要有幾個方面。首先，H3N2病毒本身變異速度快，疫苗的保護效果相對有限，尤其對老年人保護力不足。其次，疫苗接種率未達到理想水平，部分高危人群尚未接種或延遲接種。再者，流感潛伏期短且傳播迅速，即使接種疫苗，也可能出現突破性感染。此外，季節性流感與共存的其他呼吸道疾病（如新冠病毒）可能加劇醫療負擔，使疫情看似更加嚴重。

流感活動仍處於上升期，CDC預測從2026年1月至3月可能達到高峰期，尤其需警惕重症病例增加的風險。歷史經驗亦提醒人們H3N2病毒的危險性：1968年H3N2曾引發全球大流行，造成數百萬人死亡；2017-2018年美國流感季以H3N2為主導，導致7.9萬人死亡，凸顯了當前防控的迫切性。

總結來看，儘管有疫苗存在，但流感病毒特性、疫苗接種率以及群體易感性等因素，使得美國本季流感疫情依然嚴重，公共衛生部門需要持續加強疫苗接種、監測與防控措施，以降低重症與死亡風險。

According to data from the U.S. Centers for Disease Control and Prevention (CDC), approximately 2.9 million flu cases have been reported nationwide so far, with around 30,000 hospitalizations and 1,200 deaths. The current flu season is dominated by the influenza A H3N2 virus, and flu activity across the country continues to increase.

Specifically, during the week ending December 6, of 547 flu virus samples tested by public health laboratories, 96% were influenza A, primarily H3N2, while influenza B accounted for only 4%. Notably, the first pediatric flu-related death of the season was reported in the first week of December, raising concerns about high-risk populations. The CDC has distributed 127 million doses of flu vaccine and recommends that everyone aged six months and older get vaccinated as soon as possible. The agency also emphasizes the importance of antiviral medications for elderly individuals and patients with chronic illnesses to reduce the risk of severe illness and death.

Despite the availability of vaccines, the flu remains severe in the U.S. for several reasons. First, the H3N2 virus mutates rapidly, which can reduce vaccine effectiveness, particularly among older adults. Second, vaccination coverage is not yet ideal, and some high-risk groups have not been vaccinated or have delayed vaccination. Third, influenza has a short incubation period and spreads quickly, meaning breakthrough infections can still occur even among vaccinated individuals. Additionally, the co-circulation of other respiratory diseases, such as COVID-19, can exacerbate the perceived severity of the flu season by increasing the burden on healthcare systems.

Flu activity is still on the rise, and the CDC predicts that it may reach its peak between January and March 2026, with a heightened risk of severe cases. Historical data also underscore the danger posed by H3N2: the virus caused a global pandemic in 1968, resulting in millions of deaths, and during the 2017–2018 U.S. flu season, when H3N2 was dominant, 79,000 Americans died. These precedents highlight the urgency of current prevention and control efforts.

In summary, although vaccines are available, factors such as the virus’s characteristics, vaccination rates, and population susceptibility have contributed to the continued severity of the flu this season in the U.S. Public health authorities must continue to strengthen vaccination campaigns, monitoring, and preventive measures to reduce the risk of severe illness and fatalities.