本周,随着中国和其他154个国家一起转换现有脊髓灰质炎(脊灰)免疫接种程序,全球向消灭脊灰的目标又迈进了一步。新的脊灰免疫接种程序更安全,免疫效果更好,也是历史上首次全球同时将现已消灭的脊灰病毒“剔除”出脊灰疫苗的行动。此次行动将能为儿童,尤其是容易感染脊灰的儿童,提供更好的保护。
世卫组织 :走在消灭脊灰的康庄大道上
世卫组织 :走在消灭脊灰的康庄大道上
这不仅是数十年抗击脊灰行动中取得的重大成就,也是全球免疫接种史上的不朽丰碑。中国国家卫生和计划生育委员会今天发布声明,要求接种服务点停止使用三价口服脊灰减毒活疫苗。这是中国免疫程序首次,也是最重要的转换行动。这是好消息!”
脊髓灰质炎野病毒有三个血清型,相应的疫苗也包含这三个血清型的疫苗株,即目前全世界儿童接种的(三价)脊灰疫苗,但这种情况即将改变。全球于2015年宣布已经消灭其中一种脊灰野病毒,这意味着可以去除脊灰疫苗中已经消灭的病毒。
这一转换行动的重要性在于,脊灰疫苗不再需要包含已消灭的病毒;事实上,不这么做将有潜在危害:因为继续在疫苗中保留该脊灰病毒,该型别病毒将有重新传播的罕见风险。因此,世界各地正在引进仅包含两个型别脊灰病毒的新疫苗(二价疫苗)。全球同步转换疫苗计划也是必要步骤,能够避免不同步导致的野病毒重新传播而部分人却得不到疫苗保护的情况。
该转换行动作为脊灰尾声战略的关键一步,得到免疫战略咨询专家组的推荐和世界卫生大会的认可。
“脊灰是一种致残传染病,全球在消灭脊灰的道路上已经取得了长足的进步。从1988年以来,脊灰病例减少99.9%,从约35万例降低至2015年报告的80例。我们和政府以及卫生领域专家的共同目标,是帮助每一个儿童预防这种疾病,而全球疫苗转换行动让我们距离实现全球零感染的目标更近了一步。” 全球转换疫苗是实现全球无脊灰的重要一步。2015年,无论是报告的脊灰病例数量,还是报告出现脊灰病例的国家,均是历史最低值。现在,重点应是向每一个儿童提供脊灰疫苗,攻下脊灰病毒残余的堡垒。 在中国,三价口服脊灰减毒活疫苗将转换为二价疫苗,逐步将脊灰灭活疫苗引进国家免疫程序:
中国父母将见证儿童接受新的脊灰免疫程序,包括一剂脊灰灭活疫苗,后接种三剂新的两型病毒(二价)口服脊灰减毒活疫苗。脊灰灭活疫苗采用注射进行接种,而二价口服脊灰减毒活疫苗将通过口服滴液接种(不再使用“糖丸”);且口服脊灰减毒活疫苗也将逐步淘汰,最后全部采用脊灰灭活疫苗。
这个行动的另一重要性在于,在极罕见情况下(每300万剂引起1例病例),由活病毒制成的口服脊灰减毒活疫苗会造成儿童麻痹。将口服脊灰减毒活疫苗从三种型别脊灰病毒减为两种,以及逐步完全使用脊灰灭活疫苗(采用灭活病毒制成,不会引起儿童麻痹)的两项行动,将本已极其罕见的风险进一步大幅降低,使数代人用于成功预防脊灰的脊灰疫苗更加安全。
“这意味着新的脊灰免疫程序更安全,相比于现有脊灰疫苗,甚至能提供更好的保护。父母们可以相信,他们始终信任的中国免疫规划正在积极回馈,为儿童提供一个更加安全的无脊灰世界。”
世卫组织 :走在消灭脊灰的康庄大道上
“在今年世界免疫周即将结束之际,这摆脱脊灰灾难的一大进步提醒我们,免疫接种对于儿童健康至关重要。正如36年前我们消灭了天花一样,我们现在正站在历史的拐角,彻底消除脊灰指日可待。”
世卫组织 :走在消灭脊灰的康庄大道上
Eradication of polio one step closer for China, and the world
WHO/UNICEF Joint News Release
The global goal of eradicating polio is one step closer this week, as China along with 154 other countries, make the shift to a new, safer, and more immunogenic polio vaccination schedule – including an unprecedented, globally-synchronized change to ‘switch off’ a now-eradicated strand of polio virus in polio vaccines. This effort will provide better protection for children against polio, particularly those most vulnerable to infection.
“This is an important milestone in the decades-long fight against polio, and in the history of immunization globally. The notice issued by the National Health and Family Planning Commission today instructing immunization providers to stop using trivalent Oral Polio Vaccine formalizes the first, and most crucial, shift in the changed immunization schedule in China – which is great news,” said Dr Bernhard Schwartländer, WHO Representative in China.
世卫组织 :走在消灭脊灰的康庄大道上
Dr Bernhard SchwartländerWHO Representative in ChinaThere are three strains of wild polio virus, each of which have been used in polio vaccines given to children around the world (trivalent vaccines) – until now. One of the three strains of wild polio was declared eradicated in 2015 – which means that the eradicated strain can now be removed from polio vaccine.
This change is important because there is no longer a need to continue including the eradicated strain of virus in polio vaccine – and in fact there is now potential harm in doing so, because whenever this strain of polio is used in vaccine there is a very small risk it could come into circulation again. Hence, a new vaccine using only two strains of polio virus (bivalent vaccine) is being introduced around the world. It was critically important that the ‘switch off’ be synchronized globally – to remove any risk of the wild virus recirculating without a vaccine to protect against it.
世卫组织 :走在消灭脊灰的康庄大道上
This global vaccine ‘switch’ has been recommended by the Strategic Advisory Group of Experts on Immunization and endorsed by the World Health Assembly as a critical component of the polio endgame strategy. "Globally, we have made remarkable progress towards eradicating polio, a crippling infectious disease. The number of cases has decreased by over 99.9% since 1988 – from an estimated 350,000 cases to fewer than 80 reported cases in 2015. Working with the Government, and with health professionals our collective goal is to protect every child from this disease – and the global vaccine switch takes us ever closer to achieving zero infections in the world,” said Ms Rana Flowers, UNICEF Representative in China.
世卫组织 :走在消灭脊灰的康庄大道上
UNICEF Representative in ChinaThe global switch is a significant step in the effort to achieve a polio-free world. In 2015, there were fewer cases reported in fewer countries than ever before. Now, the focus is on reaching every child with the polio vaccine and stopping the virus in its remaining strongholds. In China, switching off trivalent Oral Polio Vaccine will coincide with the gradual introduction of Inactivated Polio Vaccine (IPV) into the national immunization schedule: parents will see their children receive a new polio vaccination schedule consisting of one dose of IPV, followed by 3 doses of the new two-strain (bivalent) Oral Polio Vaccine. IPV is given by injection, and the reduced OPV will be given by mouth as drops (no more sugar pills). Over time, Oral Polio Vaccine will be phased out altogether, with only IPV used.
世卫组织 :走在消灭脊灰的康庄大道上
This is also a significant change because in extremely rare cases (1 in 3 million doses), Oral Polio Vaccine, which includes live polio virus, can itself cause paralysis in children. The combined effect of reducing the number of strains of polio virus from three to two in Oral Polio Vaccine, and phasing in IPV (which cannot cause paralysis because it does not contain live virus), will greatly reduce this risk, which is already miniscule – and thus further increase the safety of this vaccine, which has been used successfully to immunize against polio for generations. “This means the new polio immunization schedule will be safer, and provide even stronger protection against the remaining types of polio. Parents can be confident that their longtime trust in China’s immunization program is delivering dividends of a safer, polio-free world for children,” said Dr Schwartländer. “At the end of this year’s World Immunization Week, this giant step toward getting rid of the scourge of polio serves as a reminder of the importance of immunization to the health of children. Just as smallpox was eradicated 36 years ago, we now stand on the cusp of having eliminated polio forever,” concluded Ms Flowers.