Swine flu has become the world's first official pandemic in 41 years after the World Health Organisation raised the alert level on the H1N1 virus from phase 5 to 6, the highest on the scale.

    The decision was made after a meeting of experts in Geneva today and comes as infections have climbed in Europe, the US, Australia, South America and elsewhere. The WHO chief, Dr Margaret Chan, yesterday examined data from eight countries with large numbers of swine flu cases.

    "The world is moving into the early days of its first influenza pandemic in the 21st century," Chan told reporters tonight, advising that countries should prepare for a second wave of cases. "The [swine flu] virus is now unstoppable."

    Raising the alert level reflects that the virus is more widespread, but not necessarily more dangerous – although there are fears that infections could overwhelm hospitals and health authorities, especially in poorer countries.

    Another 25 cases of swine flu have been confirmed in England and 26 more in Scotland, taking the UK total to 848.

    Speaking to health service managers in Liverpool at a conference of NHS trusts, the UK's new health secretary, Andy Burnham, said: "It's not a cause for alarm. It doesn't change our plans."

    Swine flu originated in Mexico in April and has spread to 74 countries, infecting more than 27,700 people and killing 140.

    Most cases have been mild, although employers are being warned to prepare for absences through illness.

    The WHO said pharmaceutical companies should start making swine flu vaccine. One manufacturer, GlaxoSmithKline PLC, said it could start large-scale production by July but large quantities would not be available for several months.

    Despite the WHO's hopes, the announcement of a pandemic will almost certainly spark panic in some countries. Fear has already gripped Argentina, where thousands of people worried about swine flu flooded into hospitals this week, bringing to near-collapse the emergency health services in the capital, Buenos Aires.

    "People might imagine a virus is now going to rush in and kill everyone," said John Oxford, a professor of virology at St Bart's and Royal London hospital. "That's not going to happen."

    There are 337 cases in Scotland and health officials in Edinburgh said 30% of them were in young adults aged 15-24.

    The Scottish health secretary, Nicola Sturgeon, said public health tactics had changed after it emerged the virus was spreading uncontrolled.

    Sturgeon told the Scottish parliament this morning that hospitalisation rates were similar to those in the US. She indicated that attempts to contain the virus had failed and the strategy would be to limit its spread. Doctors in the most-affected areas – Glasgow, Dunoon and Paisley – would be allowed to make a swine flu diagnosis in their surgeries rather than wait for specialist or laboratory tests.

    England's chief medical officer, Sir Liam Donaldson, said health officials were expecting to see more and more cases this autumn and winter with the return of the traditional flu season, and the virus might yet change and become more severe.

    There were "very strong" plans in place to deal with the flu and so far the government's approach, including closing schools where necessary, appeared to have worked well, he said.

    At the NHS Confederation conference, senior health service managers held an early-morning session to refine their emergency plans. Contingency arrangements are being drawn up to allow for hospitals and health centres to continue operating when as many as 40% of staff are off sick.

    Steve Barnett, the chief executive of the NHS Confederation, which represents most health and ambulance trusts, said: "The confirmation of a level 6 global pandemic reinforces the need for the NHS to ensure all the flu plans already in place at local level are as comprehensive as possible and thoroughly tested.

    "We need to avoid complacency in dealing with a virus that is an unknown and seems to be spreading quickly."

    The last such pandemic was the Hong Kong flu of 1968 that killed about a million people. Ordinary flu kills about 250,000 to 500,000 people each year.

    世界衛生組織宣布將甲型H1N1流感病毒的警戒級別由5級提升至最高級別6級，至此，豬流感已成為41年來世界上第一個正式的全球大流行病。

    鑒于歐洲、美國、澳大利亞、南美洲及世界其他地方的感染病例不斷增加，今天在日內瓦召開的專家會議宣布了這一決定。世衛總干事陳馮富珍（Margaret Chan）博士昨天審查來自八個豬流感病例最多的國家的統計數據。

    "世界正進入二十一世紀第一場全球流感大流行的初期階段，"陳總干事今晚告訴記者，她建議各國應該做好準備應對流感第二波疫情的出現。"目前這[豬流感]病毒的流行是無法阻止了。"

    提高警戒級別表明病毒傳播愈加廣泛，但并不一定意味著病毒本身愈加危險--盡管有些人擔心病毒感染的事態會發展到令醫院和衛生主管部門無法應付，尤其是在較貧窮國家。

    英格蘭又有25個豬流感確認病例，蘇格蘭另有26個，英國的流感確認病例總數上升為848例。

    在利物浦召開的英國全民醫療保健系統信托組織（NHS trusts）會議上，英國新任衛生大臣安迪·伯納姆（Andy Burnham）對與會的公共醫療衛生服務主管們說："不必驚慌。我們的計劃不變。"

    豬流感于今年4月在墨西哥爆發，現已蔓延到74個國家，感染人數超過27700人，死亡人數達140人。

    雖然已預先告知雇主做好應對員工因病缺勤的準備，但目前來看，大多數病例的病情溫和。

    世衛組織建議制藥公司應該開始抓緊生產豬流感疫苗。英國制藥商葛蘭素史克公司（GlaxoSmithKline PLC）宣布，公司7月份之前可以開始大規模生產豬流感疫苗，但幾個月內無法供應大量疫苗。

    盡管世衛組織希望大家保持鎮定，宣布全球大流行肯定會在一些國家引發恐慌。阿根廷已經籠罩在恐懼之中，本周數以千計擔心豬流感的人涌入各家醫院，導致首都布宜諾斯艾利斯的緊急醫療服務接近崩潰。

    "人們可能以為這種病毒現正在迅速蔓延而導致每一個人病亡，"圣巴特及皇家倫敦醫院的病毒學教授約翰·奧克斯佛（John Oxford）說，"這絕不會發生。"

    在蘇格蘭有337個豬流感病例。愛丁堡的衛生官員指出，其中30%的感染者是年齡在15歲至24歲的年輕人。

    蘇格蘭衛生部長尼古拉·斯特金（Nicola Sturgeon）表示，自從豬流感病毒的蔓延失控之后，公眾衛生部門的應對策略已有所改變。

    斯特金今天上午在蘇格蘭議會上報告，蘇格蘭豬流感病例的住院率和美國大致相同。她表示，控制病毒的努力已經失敗，現在的策略是限制病毒傳播。豬流感病毒感染最嚴重的地區--格拉斯哥（Glasgow）、丹農（Dunoon）及佩斯利（Paisley）的醫生將被允許在各自的診所現場進行豬流感診斷，而不需等待專家或化驗。

    英格蘭首席醫務官利亞姆·唐納森爵士（Sir Liam Donaldson）表示，衛生官員們預期，隨著傳統流感季節的到來，今年秋冬兩豬流感病例會越來越多，而且這種病毒可能還會變化，變得更加嚴重。

    他說，政府已部署了"非常有力"的計劃來應對豬流感，迄今為止，政府的應對措施，包括必要時關閉學校，看來效果良好。

    在英國國家衛生服務聯盟（NHS Confederation）會議上，公共醫療衛生服務的高級主管們舉行了一次晨會，旨在優化他們的應急計劃。正在擬訂的應變計劃為醫院和保健中心在多達40%的工作人員因病缺勤的情況下繼續運作提供了適當安排。

    代表大多數衛生及救護信托組織的英國國家衛生服務聯盟的行政長官史蒂夫·巴內特（Steve Barnett）說："全球大流行病6級警戒級別的確認，更增強了國家衛生服務體系（NHS）的重要性，以確保所有已制定的在地方級流感應對計劃盡可能全面、盡可能經過徹底驗證。

    "在應對這個似乎正迅速蔓延而又未知的病毒方面，我們必須避免有自滿情緒。"

    上一次發生的全球大流行病是1968年的香港流感，那次約有100萬人死亡。普通流每年造成25萬至50萬人的死亡。