疫苗與衛生保健是使H1N1傳染最小化的關鍵

作者：Paula Moyer  
出處：WebMD醫學新聞

　　September 26, 2009 — 好消息！新型A型流感(H1N1)的疫苗在10月中將上市，將可以讓更多人因而具有免疫力，而且該病毒的基因組成迄今仍未改變。
　　
　　疾病控制與預防中心主任Thomas R. Frieden醫師日前在記者會簡報中表示，病毒的基因穩定表示疫苗可以有高度效力。
　　
　　此外，對於10歲以上者，新核准的H1N1流感疫苗一劑即可有效。
　　
　　他表示，對於預防病毒擴散，一般的衛生保健實務常識也一樣重要。醫師應告訴病患或他們的小孩，延後回到工作崗位或學校，除非體溫恢復正常24小時且未使用退燒藥物之後，每個人在咳嗽時要遮住口鼻且勤洗手。罹患流感的病患，如果有併發症風險或重症如呼吸短促或高燒，應使用適當的抗病毒藥物治療。他表示，流感症狀開始後48小時內使用抗病毒藥物效果最大。
　　
　　Frieden醫師總結了迄今有關H1N1已知和未知的相關議題。舉例來說，已知H1N1流感似乎是程度中等的疾病，因此沒有比一般的流感病毒株嚴重；主要影響的仍然是孩童和年輕成人：其盛行率似乎有下降趨勢。
　　
　　不過，如同所有的流感病毒株，有許多無法預測的狀況也不令人意外。他表示，流感是最變化莫測的傳染病。有關H1N1的未知議題，舉例來說，不知道下降趨勢是否意味著H1N1將永久消失或將再度捲土重來。同樣地，流行病學家不知道是否會發生其他的流感季節，例如今年最常見的H3流感病毒引起的案例。
　　
　　Frieden醫師表示，廣為散佈之已知因素的相關錯誤資訊也是適當防疫的障礙之一。他指出，錯誤資訊傳播得比病毒快。醫師需釐清這些令人擔心的錯誤觀念與過度自信的認知。舉例來說，醫師應向病患強調，不可能因為施打疫苗而罹患流感，因為疫苗是由殺死的病毒製成。相反地，病患應避免過度相信流感不是嚴重疾病的這個錯誤認知，以免認為施打疫苗是不必要的。
　　
　　從藥廠疫苗生產、將貨上到冷藏卡車、送到9萬處以上的機構讓病患施打，這之間還有諸多障礙要克服。因此，即使每個需施打疫苗的人在10月中下旬可能可以接種，屆時仍可能會有一段時間供貨不足，之後才會補足。應立即施打H1N1疫苗者包括有併發症風險者，例如原本即有慢性健康疾病者、此類病患的照護者、共同生活的家人，以及和無法接受疫苗的6個月以下嬰兒一起生活者或其照護者。

Vaccines, Hygiene Key to Minimizing H1N1 Spread

By Paula Moyer
Medscape Medical News

September 26, 2009 — The good news is that the vaccine against influenza A (H1N1) will be available by the middle of October, that more people are getting immunized against influenza than in the past, and that the virus's genetic make-up is not changing.

The genetic stability means that the vaccine is highly likely to be effective, said Thomas R. Frieden, MD, MPH. Dr. Frieden, the director of the Centers for Disease Control and Prevention, spoke yesterday at a press briefing.

In addition, the newly approved vaccines against H1N1 influenza appear to be effective after a single dose in people aged 10 years and older.

Commonsense hygiene practices are also critical to preventing the virus from spreading, he said. Physicians should tell patients or their children to defer returning to work or school until 24 hours after body temperature has returned to normal without fever-reducing medication, and all people should cover coughs and wash hands frequently, he said. People who do get influenza should be treated promptly with antiviral medication only if they are at risk for complications or if they become severely ill, such as with shortness of breath or a high fever. Antiviral medication must be initiated within 48 hours of the onset of influenza to be maximally effective, he said.

Dr. Frieden summed up the known and unknown issues to date regarding H1N1. For example, it is known that H1N1 influenza seems to be a moderate disease, and therefore no more severe than the strains of influenza typically seen; the pattern of affecting primarily children and young adults is holding; and its prevalence seems to be on a downward trend.

However, as with all strains of influenza, unforeseen curves and bumps in the road are the rule, not the exception. "Influenza is the most unpredictable of contagious diseases," he said. What is unknown about H1N1 illustrates this point. For example, it is not known whether the trend downward indicates that H1N1 will retreat permanently or whether it will return. Similarly, epidemiologists do not know whether another flu season will occur, in this case driven by H3 influenza, the more common strain in circulation this year.

The widely spreading misinformation is one of the known factors that is a barrier to adequate immunization, Dr. Frieden said. "Misinformation spreads more rapidly than influenza," he added. Physicians need to clarify misconceptions that are alarming and those that promote complacency. For example, physicians should stress to their patients that it is impossible to get influenza from the vaccine because it is based on a killed virus. Conversely, patients should be steered away from the complacency-inspiring misconception that influenza is not a severe illness, and therefore vaccinations are unnecessary.

There are also daunting logistical barriers to getting the vaccine out of the manufacturing plants, onto refrigerated trucks, and out to the 90,000-plus facilities that administer the vaccine to patients. Therefore, even though everyone who should get the vaccine should have had the opportunity by mid- to late October, there may be a temporary shortage earlier in the month until the distribution is complete. Those who should get the H1N1 vaccine sooner are people who are at risk for complications, such as those with underlying chronic health conditions, caregivers of such patients, those who live with them, and people who live or work with infants younger than 6 months, who are not able to tolerate the vaccine.