KHOA HQC K t T H U A T THU Y TAP XIX S6 3-2012
SAN XUAT VACXIN CUM GIA CAM NAVET-VIFLUVAC, CHUNG NIBGR-14 a VIET NAM
Trdn Xudn Hgnh Trung tdm nghien cim thdy - Cong ty NA VETCO
Sdn xuit vacxin ciim gia cim Id mOt edng vifc phdc tfp, ddi hdi ky thuft cao vd dilu kifn sdn xuit nghiem ngft. Hifu qud ciia vacxin phy thufc rit nhilu vdo chit lupng gilng virut, dfc bift tfnh tuong ding cda chdng virut vacxin vdi chung virut gdy bfnh vd hdm lupng protein HA chda trong lilu vacxin. Ngudi ta dd chdng minh dupc nlu trinh tvr cdc axit amin giiia chdng vacxin vd chiing gdy bfnh gilng nhau khodng 87% la cd mli tuomg quan rit rd din hifu qud phdng bfnh.
Thvrc tl d Vift Nam dd chirng minh sd dvmg vacxin phdng bfnh kit hpp vdi bifn phdp vf sinh phdng bfnh khde cd y nghTa quylt djnh din hifu qud phdng ching bfnh cum gia cim. Qua nhilu ndm sd dyng vacxin cum gia cim do Trung Quoc sdn xuit cho thiy vacxin cd chit lupng vd dem Ifi hifu qud phdng bfnh tit, tinh hinh gia cim bj bfnh cum gidm, khdng ed cdc I djch ldn xuit hifn vd gidm sdt ede ddn gia cim sau tidm phdng eho thiy mien djch quan thi ludn dft d ngudng bdo hf. Vi vfy, sd dyng vacxin phdng bfnh cum gia cim dd Id mft trong ede bifn phdp phdng bfnh khdng thi thilu d nudc ta, tuy nhidn hfn chl chinh Id d chl do phdi nhfp khiu vacxin ndn ehi phf cao vd vife cung cip khdng dupc chd dfng.
D I timg budc gidi quylt nhiing khd khdn trong vife cung e ^ vacxin phdng bfnh ciim gia cim cho dan gia cim nudi d Vift Nam, trdn eo sd kit qud nghien cdu cda dl tdi "Nghien cihi xdy dimg qui trinh sdn xudt vacxin cdm A/H5N1 cho gia cdm " do Vifn edng nghd sinh hpc chu tri, vdi svr tham gia thvrc hifn cua Cdng ty thuic thii y TW NAVETCO, Xf nghifp thuic thu y TW VETVACO vd Vifn thd y NIVR. Cdng ty thuic thd y TW NAVETCO dd dupc Bf
khoa hpc vd edng nghf vd Bf Ndng nghifp &
PTNT giao thye hifn dy dn "Sdn xudt thu nghifm vacxin cdm A/H5N1 nhu ddu di phong chong bfnh cho gia cdm "
Gilng virut cum chiing NIBRG 14, dupc diing dl nghidn cdu chl tfo vacxin, dupc tfo ra trdn CO sd ky thuft di truyin ngupc vdi chiing glc Id chdng virut cum A/Vietnam/1194/2004 (H5N1) phdn Ifp trfn bfnh nhdn nhilm bfnh cum. Chiing virut ndy gilng vdi nhOmg chiing virut ciim phdn Ifp trdn cdc lodi gia cam vl mft khdng nguydn vd khdng nguydn gdy ngung kit hing ciu (HA) mang mft chuli cdc axit amin kilm dfc trung cho cdc chiing cum gia cim dOc Ivrc cao. Nhd ky thuft di truyin ngupc (reverse genetic), cdc nhd khoa hpc thuOc Vifn quic gia vl Tidu chuin vd Kilm djnh sinh hpc (NIBSC) Vuong quic Anh da nghidn cdu phdt triln mft chiing khdng cd dOc lyc nhd sd dyng hf thing 12 plasmid, bao gom: 2 plasmid mang dofn gen HA vd NA cda virut A/Vietnam/1194/2004 (H5N1);
6 plasmid mang 6 dofn gen cdn Ifi cda virut cdm PR8; 4 plasmid bilu hifn ehdc ndng hi trp cda virut PR8. Sau khi tilp nhfn vd nhan gilng, kilm tra vl gen cda chdng NIBRG -14 sau ede lin ciy ehuyin qua phdi trdng gd vd bdo qudn d cdc dilu kifn khde nhau eho thiy gilng virut vacxin khdng ed svr thay dii vl mft di truyin, sdn phim thu dupc ddng nhu ly ljch gilng glc cda miu dii chimg do NIBSC cung cip.
Hifn nay vacxin cum gia cim H5N1 dupc sdn xuit dung cdng nghf nudi ciy virut tren phdi gd 10 11 ngdy tuli. Vifc xdc djnh dupe ning df virut gdy nhilm, nhift df nudi ciy, thdi gian thu hofch thfch hpp dl cd thi thu dupe djch nifu md vdi hifu gid virut eao vd In djnh Id ylu t l quylt
89
KHOA HQC KV T H U A T THLJ Y TAP XIX S6 3 - 2012 djnh din thdnh cdng vd ddm bdo tfnh kinh tl khi
sdn xuit vacxin cdm gia cim. Trdn co sd cdc thilt bj hifn cd, lyc lupng lao dfng ky thuft chuyfn sdu vl sdn xuit vacxin vd nguin cung cip tning ed chit lupng In djnh, cdng ty NAVETCO budc diu dd sdn xuit dupc nhilu trifu lilu vacxin cdm gia cim H5N1 dft tidu chuin vl vft ly, vd trdng, an todn vd hifu lye.
D I sdn xuit dupc vacxin ciim gia cim vd hoft nhd diu cd chit lupng, ngodi cdc ylu tl vl gilng virut, dilu kifn nudi ciy thfch hpp, vife nghidn ciru cd dupe mft cdng thdc nhQ In djnh cdng Id mOt ylu tl mang tfnh quylt djnh din chit lupng cua sdn phim vd ddp dng dupc ydu ciu khi sdn xuit d qui md cdng nghifp. Trfn co sd cdc nghidn ciiru trudc ddy vl vacxin nhQ diu (vacxin ty huylt trimg trdu bd nhQ diu, vacxin ty huylt trimg gia cim v.v.), chung tdi dd cdi tiln, xdc djnh edng thdc phii trfn thfch hpp dl sdn xuit thdnh cdng vacxin cum gia cim nhQ diu chdng NIBRG 14 vd thda mdn cdc dilu kifn Id nguyfn lifu de kilm, gid thdnh chip nhfn dupc, vd dfc bift dft cdc ydu ciu ddi hdi cua vacxin nhQ diu nhu: dO nhdt thip, dl tidm, phdn img thip. Bdng phuong phdp ly tdm dl kilm tra tfnh In djnh vd dung phuong phdp do toe dO chdy cda vacxin dl kiem tra dO nhdt, kit qud cho thiy vacxin NAVET - VIFLUVAC dft cdc tidu chuin vl tfnh In djnh cung nhu dO nhdt vd cd chit lupng tuomg duomg vdi vacxin cum gia cim do cdc cdng ty cda Trung Quic sdn xuit khi dupe bdo qudn trong cung mOt dilu kifn td 2 - 8°C.
Theo ddi tfnh In djnh eiia nhQ diu trong thdi gian bdo qudn cho thiy vacxin khdng ed hifn tupng ehuyin mdu, khdng tdch pha nudc. Cdc chl tidu vl tfnh In djnh, df nhdt vln dft ydu ciu nhu kilm tra d thdi dilm sau khi sdn xuit. Tuy nhidn khi bdo qudn d dilu kifn lfnh trong thdi gian ddi, quan sdt thiy cd mft Idp diu tdch ra td 0,1 0,3nim trdn bl mft vacxin vd trong mOt sl trudng hpp cd thi hinh thdnh mOt Idp efn d dudi ddy Ip vacxin. Hifn tupng ndy dd dupc kilm tra vd xdc nhfn khdng dnh hudng din chit lupng cda vacxin.
An todn vd hifu lye eiia vacxin ciim gia cim H5N1 chdng NIBGR-14 dd dupc kilm tra, ddnh
gid trong dilu kifn phdng thf nghifm vd trong dilu kifn sdn xuit. Kit qud kilm tra dd chdng minh vacxin ed tfnh an todn trfn gd, vjt khi tidm vdi mft lilu (lilu sd dyng) hay gip 2 lin lilu sd dyng cho gd, vjt d cdc Ida tuli khde nhau td 1, 14, 21 vd 30 ngdy, vdi cdc chi tidu theo ddi, bao gim: phdn iimg d vj trf tidm, phdn img todn thdn, sing, chit vd dnh hudng sau khi tidm vacxin din sinh trudng vd phdt triln cda gia cim.
Trong dilu kifn phdng thf nghifm, hifu lyc cda vacxin dupc kilm tra trdn gd, vjt vd dung phucmg phdp huylt thanh hpc dl ddnh gid. Kit qud eho thiy gd, vjt khi tidm vacxin d 3, 4 tuin tuli diu cho ddp dng khdng thi tit. Cd sy khde nhau rd rft vl hifu gid trung binh khdng thi HI gida Id gia cim dupc tidm mft lin vd tidm vacxin hai lin. Dii vdi gd khi tidm vacxin d 3 tuin tuli vdi qui trinh mOt mQi, hifu gid trung binh khdng thi biln dOng td 3,5 3,9log2, hiy nhidn gid trj ndy tdng cd y nghTa khi gd dupc tidm nhdc Ifi mQi 2, vdi gid trj GMT thu dupc la 6,3 - 6,7Iog2. Svr khde bift vl ddp dng khdng thi cQng nhfn thiy khi so sdnh gd tidm d 3 tuin tuli vd 4 tuin tuli. Q gd 4 tuin tuli, mfe du chi tidm mft mQi hifu gid trung binh HI dd dft d miic cao Id 4,8 5,2Iog2 vd d Ida tuli ndy nlu tidm nhdc Ifi mQi 2, hifu gid HI cQng dft dupc d mdc rit cao 7,5 7,61og2.
Trudng hpp d vjt, ddp img khdng thi sau khi tifm vacxin cQng gilng nhu trfn gd. Tuli vjt tidm vacxin, sl lin tidm vacxin cd dnh hudng din ddp irng khdng thi, tuy nhidn kit qud chi ra rdng d^
dng khdng thi tren v|t thudng thip hon trdn gd khi thf nghifm dupc thvrc hifn trong cdng mft dilu kifn vl tuli gia cim sd dyng vd sl lin gdy miln djch. Miirc df khde nhau vl hifu gid khdng thi HI thu dupc khi tidm vacxin d cdc lira tuli khde nhau cd thi lidn hf din mdc df khdng thi bj dOng cdn tin tfi d gia cim thf nghifm td nhdng gd, vjt md m? dupc tidm vacxin cum hofc bj nhilm bdi ede chdng virut cum thi dOc lvrc th^.
Thyc nghifm trfn dilu kifn sdn xuit, vacxin dupe tidm cho gd, vjt d cdc Ida tuli khde nhau (2, 3 tuin) vdi cdc qui trinh tidm phdng khde nhau:
1 mQi hofc nhdc Ifi mQi thd 2 sau 3 tuin tidm
90
KHOA HQC K t T H U A T THLJ Y TAP XIX S6 3 - 2012 miii thd nhit. Sau 3 tuin tidm vacxin, gd vjt
miln djch cdng doi chdng dupc liy mdu kilm tra ddp img khdng thi vd phan Id, mli Id 10 gd (vjt) vd 5 dii chdng dl tiln hdnh thd thdch cudng dfc tfi Trung tam chin dodn thu y TW, dimg virut ciim gia cim H5N1 cudng dOc vdi cdc clade 1, clade 2.3.2.1a vd clade 2.3.2.1b, lilu 10*
TCIDso/con/nhd mQi.
Ket qud chi ra rdng khi tidm vacxin eho gd d 2 tuin tuli vd kilm tra ddp dng khdng thi sau 3 tuin, ed 60% gd cd ddp img khdng thi vdi hifu gid HI trung binh Id 3,5Iog2, tuy nhifn nlu gd dupc tidm nhdc Ifi lin 2 sau 3 tuin, 100% gd kilm tra ed khdng thi vd hifu gid HI trung binh dft d ngudng cao 6,46 Iog2. Dii vdi gd tidm vacxin vdo 3 tuin tuli thi ty If miu cd ddp umg khdng thi cao hom (76,6%) so vdi gd tidm vacxin d 2 tuin tuli vd hifu gid HI trung binh dft d mdc 4,01og2.
Dii vdi vjt, ddp irng khdng thi ehi dft ty If 50% khi tidm vacxin cho vjt d 2 tuin tuli vd HI trung binh dft dupc Id 3,2Iog2. Tuy nhidn, ddp dng khdng thi d vjt dd tdng din 90% khi vjt dupc tidm nhdc Ifi mQi 2 vd gid trj HI trung bhih dft Id 4,7.
Phan tich kit qud cdng cudng dfc trdn gd cho thay mfe du trung binh hifu gid khdng thi Id gd tiem vacxin d luc 2 vd 3 tuin tuli khdng khde bift nhilu (3,3 3,7Iog2 so vdi 3,7 4,41og2), nhung cd sy khde bift vl ty If bdo hf khi cdng thd thdch vdi virut cum H5N1 clade 1 vd clade 2.3.2.1a, 80% so vdi 60%. Kit qud khde nhau ndy cd thd lidn quan den svr khde nhau vl ty If gd cd ddp dng khdng thi sau khi tidm vacxin gida Id tidm d 3 tuin tuli (76,6%) vd Id tidm d 2 tuin tuli (60%). Tuy nhidn sau 3 tuin kl td mui tidm thd nhit, gd dupe tidm nhdc ifi mui 2 vd thd thdch cudng dfc sau 3 tuin, 80% gd dupc bdo hO vdi clade 1; 100% bdo hO vdi clade 2.3.2.1a vd
10% bdo hO vdi clade 2.3.2.1b.
Ty If bdo hO cao cung dupc ghi nhfn d Id gd tidm vacxin 1 mui d thdi dilm 3 tuin. Kit qud chi ra ring khi tidm vacxin cum gia cim eho gd d 3 tuan tuli vd sau 3 tuin fhd thdch cudng dfc, 80% gd dupc bdo hO khi edng vdi clade 1 vd clade 2.3.2.1a
vd khdng bdo hO vdi clade 2.3.2.1b. Gd tidm vacxin d 2 tuin tuli vd dupe tidm nhdc Ifi sau 3 tuin, ty If bdo hO khi cdng cudng dfc cung dft cao, biln dOng td 80 - 100% khi cdng vdi clade 1 vd clade 2.3.2a vd 10% vdi clade 2.3.2.1b.
Thf nghifm cdng cudng dfc trdn vjt, sau khi tidm vacxin 1 mQi vd cdng cudng dfc sau 3 tuin ty If bdo hO dft 80 % khi cdng vdi clade 1; 100%
vdi clade 2.3.2.1a vd 0% vdi clade 2.3.2.Ib, trong khi vjt dii chiimg chit 80% vdi clade 1; 40% vdi clade 2.3.2.1a vd 100% vdi clade 2.3.2.1b.
Trudng hpp vjt dupc tidm vacxin 2 mui, mui sau cdch mQi trudc 3 tuin ghi nhfn 100% vjt dupc bdo hO vdi clade 1 vd clade 2.3.2.1a, vd 30% bdo hO vdi clade 2.3.2.1b, trong khi dd dii chdng ciia clade 1 chit 80%, clade 2.3.2.1a chit 40% vd clade 2.3.2.1b dii chdng chit 100%. Ket qud thu dupe ghi nhfn cd sy khde nhau vl tinh man cdm cda vjt vd gd dii vdi virut eiim gia cim H5N1 clade 2.3.2.1a, vi trong khi clade 2.3.2.1a gay chit 100% gd doi chimg thi tren vjt chi gay chit 40%. NIU edn ed vdo ty If bdo hf cda gd mien djch khi cdng cudng dOc vdi virut ciim gia cim H5N1 clade 2.3.2.1a thi cd sy tuomg ding rd rang vl khdng nguyen bdo hO gida virut vacxin chiing NIBRG-14 vd virut cudng dOe clade 2.3.2.1a.
Vdi kit qud thu dupc, rd rang nlu vjt dupe tiem phdng vacxin NAVET VIFLUVAC cQng cd the bdo hO ching Ifi virut cum gia cam H5N1 clade 2.3.2.1a vd thyc tl cho thiy khi tidm vacxin cho vjt cd tdc dyng bdo hO khd rd rang khi cdng cudng dOc eho vjt, vdi vjt dii chdng chit 40%, trong khi dd vjt Id miln djch sing 100%. Ngudi ta cung cd thi phdn bifn vi ty If dii chdng chit diip khdng dft ydu ciu, do vfy khdng ddnh gid dupc tdc dvmg cua vacxin, tuy nhidn d y kien ngupc Ifi ed thi ndi nlu khdng tidm vacxin, vjt nudi sd cd 40% bj chit nlu nhu vjt bj nhilm virut cum gia cim clade 2.3.2. la.
Nhu vfy edng cudng dfc cho gd khi tidm vacxin 1 mQi d 21 ngdy tuli vd 2 mQi (mui diu d 14 ngdy tuli vd nhdc Ifi sau 3 tuin - bdng 3) ty If bdo hO dft td 80 100% khi cdng vdi virut cdm gia cim H5N1 clade 1 vd clade 2.3.2.1a, trong khi dd Id dii chdng 100% gd chit. Trdi vdi kit qud thu dupc trdn, khi cdng thd thdch vdi chdng 91
KHOA HQC K t T H U A T T H O Y T A P XIX S6 3-2012 virut cum H5N1 clade 2.3.2.Ib, bdo hO ldm sdng
ehi dft 10% dii vdi Id tidm vacxin 2 lin. Dilu ndy chdng td vacxin sdn xuit td chdng virut vacxin NIBRG-14 cd khdng nguydn bdo hO tuong iimg vdi chdng virut cdm cudng dOc H5N1 clade 1 vd clade 2.3.2.1a, nhung khdng tuomg thfch vdi virut cdm H5NI clade 2.3.2.1b. Tuy nhifn dl ed thi ddnh gid chfnh xdc mdc df bdo hO cda vacxin chda chdng NIBGR-14 dii vdi chdng cudng dOc H5N1 clade 2.3.2.1b, thfm chf cd clade 2.3.2.1a, cin thilt phdi cd nhdng nghifn cdu sdu vl Idm sdng, dfc bift tiln hdnh ede thf nghifm bdo hf ehdo vdi virut ddng cdng cudng dOc khi dd xdc djnh dupc tfnh In djnh vl dOc lye vd lilu edng dupc chuin hda.
Kit qud cQng chirng minh ed khde nhau vl mdc do ddp img khdng thi vd ty If bdo hf khi cdng cudng dOe dii vdi gd dupc tifm vacxin d 2 hay 3 tuin tuli vd hifn tupng ndy ed thi cd lidn quan den mdc df tin tfi cda khdng thi thy dOng d gd dupc tidm phdng. Trdn co sd cda kit qud ndy, chung tdi dl nghj: Trong nhdng vung djch tl phdc tfp, nguy co bfnh cdm gia cim xdy ra cao, ndn tidm vacxin eho gd vdo thdi dilm 14 ngdy tuli vd nhdc Ifi mQi 2 sau 3 tuin. Q cdc vung ft bj uy hilp, tidm vacxin eho gd vdo ngdy tuli 21 hofc Idn hom vd chi tidm mft mQi.
Nhhi chung mdc dO ddp dng khdng thi phdn dnh tinh trfng miln djch cda dOng vft dupc tidm vacxin, tuy nhidn mli lofi vacxin, thfm chf cdng mft iofi vacxin nhung do cdc eo sd khde nhau sdn xuit cd thi cd ede tidu chuin khde nhau, miln Id vacxin phdi ed mOt kit qud chung Id bdo hO dupc dan gia cim tidm phdng ching Ifi bfnh d mdc dO chip nhfn dupc. Hom nOa phuomg phdp ddnh gid dupc cho Id phuomg phdp chuin "Gold"
trong nghifn ciiru sdn xuit vacxin Id phuong phdp thd thdch cudng dfc tryc tilp trfn bdn dfng vft vd thdng qua kit qud cdng cudng dfc, chdng ta ed thi thn dupc mli lifn hf vd xdc djnh dupc ngudng khdng thi md d dd khi cdng cudng dOc, dOng vft cd thi dupc bdo hf. Nlu theo ydu ciu hifu gid HI trung binh phdi dft Id > 4Iog2 thi vifc tidm vacxin eho gd mft mQi d 2 tuin tuli Id thip hom so vdi ydu ciu, trong khi d6 Id gd tidm d thdi
dilm 21 ngdy tuli vd Id gd tidm 2 mQi, cQng nhu Id vjt tidm 2 mQi diu dft ydu ciu vl mdc dO ddp iimg khdng thi. Cdn ed vdo kit qud cdng cudng dOc vd mli lidn hf gida gid trj HI trung bhih thu dupe vd kit qud thd thdch cudng dfc vdi cdc clade virut cum gia cim H5N1 khde nhau do Cdng ty NAVETCO vd Trung tdm chin dodn thii y TW thyc hifn thi gd, vjt dupe tifm vacxin NAVET VIFLUVAC, vdi lilu 0,5ml/con cd ddp dng khdng thi > 3,51og2 Id dft ydu ciu vd cd khd ndng bdo hf vdi virut cum H5N1 thi dOc lyc cao clade 1, clade 2.3.2.1a.
Trdi qua 6 ndm (2006 2012), bdt diu td dl tdi dOc Ifp cip nhd nudc "Nghiin am xdy di/mg qui trinh sdn xudt vacxin cum A/H5N1 cho gia cdm" do Vifn cdng nghd sinh hpc ehd tri, din dy dn "Sdn xudt thir nghifm vacxin cdm A/H5N1 nhS ddu di phong chong bfnh cho gia cdm" do Cdng ty thuic thd y TW NAVETCO chd tri vd thyc hifn, din nay chung ta dd sdn xuit thdnh edng vacxin ciim gia cim H5N1 vd hoft nhQ diu dft chit lupng vl: vft ly, vd trung, an todn vd hifu lyc. Trfn eo sd kit qud kilm tra chit lupng cda Trung tdm kilm nghifm thuic thd y TWl vd kit qud khdo nghifm dupc thvrc hifn giiia Cdng ty NAVETCO vd Trung tdm chin dodn thu y Trung uong, vacxin ciim gia cim H5N1 vd hoft nhQ diu, chdng NIBRG-14 dd chfnh thdc dupc Bf Ndng nghifp & PTNT, Cyc thu y eho phdp sdn xuit vd sd dyng theo quylt djnh s l 04/QLT.SX
12 vdi s l ddng ky TW II-I37. Thdnh edng ndy Id minh chirng cho svr hpp tdc cd hifu qud gida cdc Vifn nghidn cdu vdi cdc co sd sdn xuit vd chdng minh dupc khd ndng trong nghidn ciiru vd sdn xuit vacxin cda cdn bO khoa hpc ky thuft d nudc ta. Hifn tfi vdi dfi ngQ cdn bO khoa hpc ky thuft cd nhilu kinh nghifm trong ITnh vvrc sdn xuit vacxin vd nhthig trang thilt bj chuydn ddng hifn ed, Cdng ty NAVETCO cd khd ndng sdn xult vacxin cdm gia cim H5N1 dft chit lupng sd dyng d qui md cdng nghifp, trudc mdt bdo ddm cung dp mOt phin vacxin, tiln tdi sdn xuit thay thi hodn todn vacxin nhfp khiu dl phye vy cho cdng tdc tifm phdng bfnh ciim cho ddn gia cim nudi d nudc ta trong tuong lai./.
92
