Brammer L, Fukuda K, Arden N, Schmeltz L M, Simonsen L, Khan A, Regnery H L, Schonberger L B, Cox N J
Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, USA.
MMWR CDC Surveill Summ. 1997 Jan 31;46(1):1-12.
PROBLEM/CONDITION: CDC conducts active surveillance annually from October through May on the emergence and spread of influenza virus variants and the impact of influenza-related morbidity and mortality. Influenza activity is also monitored throughout the year by passive surveillance.
This report summarizes U.S. influenza surveillance from October 1992 through May 1994.
Influenza surveillance comprises four components, three of which provide weekly data from October through May: a) state and territorial epidemiologists provide estimates of local influenza activity; b) approximately 140 sentinel physicians report their total number of patient visits and the number of cases of influenza-like illness; and c) approximately 70 collaborating laboratories of the World Health Organization (WHO) report weekly influenza virus isolations and submit selected influenza isolates to CDC for antigenic analysis. Throughout the year, vital statistics offices of 121 cities report deaths related to pneumonia and influenza (P&I), providing an index of the impact of influenza on mortality.
Influenza B viruses predominated during the 1992-93 influenza season, but influenza A(H3N2) isolates increased and were associated with outbreaks in nursing homes at the end of the season. The increase in influenza A(H3N2) activity was associated with a rise in P&I-related mortality. Preseason outbreaks of influenza A(H3N2) virus were reported during August and September 1993 in Louisiana. In the past, preseason outbreaks of influenza have been associated with earlier than usual epidemic-level activity. During the 1993-94 influenza season, activity rose during November and December and peaked earlier than usual, during the last week of December and the first week of January; influenza A(H3N2) viruses predominated.
The change in predominance from influenza B to influenza A in the spring of 1993 emphasizes the importance of annual influenza surveillance. Although influenza vaccine is effective against both influenza A and B, the antiviral drugs amantadine and rimantadine are effective only against influenza A. Outbreaks during the summer of 1993 emphasize that influenza should be considered a possible cause of respiratory infections during summer and early autumn.
Surveillance data were provided weekly throughout the influenza season to public health officials, WHO, and health-care providers.
问题/状况：美国疾病控制与预防中心（CDC）每年10月至次年5月对流感病毒变异株的出现与传播以及流感相关发病和死亡情况进行主动监测。全年还通过被动监测对流感活动进行监测。
本报告总结了1992年10月至1994年5月期间美国的流感监测情况。
流感监测包括四个部分，其中三个部分在10月至5月期间每周提供数据：a）州和地区流行病学家提供当地流感活动的估计数据；b）约140名哨点医生报告其患者就诊总数及流感样病例数；c）世界卫生组织（WHO）约70个合作实验室每周报告流感病毒分离情况，并将选定的流感分离株提交给CDC进行抗原分析。全年，121个城市的生命统计办公室报告与肺炎和流感（P&I）相关的死亡情况，提供流感对死亡率影响的指标。
在1992 - 1993年流感季节，乙型流感病毒占主导，但甲型（H3N2）流感分离株数量增加，并与该季节末疗养院的疫情爆发有关。甲型（H3N2）流感活动的增加与P&I相关死亡率的上升有关。1993年8月和9月在路易斯安那州报告了甲型（H3N2）流感病毒的季前疫情爆发。过去，流感季前疫情爆发与比平常更早达到流行水平的活动有关。在1993 - 1994年流感季节，活动在11月和12月上升，并比平常更早达到高峰，在12月的最后一周和1月的第一周；甲型（H3N2）流感病毒占主导。
1993年春季流感优势株从乙型转变为甲型，这突出了年度流感监测的重要性。虽然流感疫苗对甲型和乙型流感均有效，但抗病毒药物金刚烷胺和金刚乙胺仅对甲型流感有效。1993年夏季的疫情爆发表明，在夏季和初秋期间，应将流感视为呼吸道感染的可能病因。
在流感季节期间，每周向公共卫生官员、WHO和医疗服务提供者提供监测数据。
