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<\/a><\/div>\n“Endi\u015fe Verici Varyant” (VOC) ve “\u0130zlenmesi Gereken Varyant” (VOI)<\/h4>\n
D\u00fcnya Sa\u011fl\u0131k \u00d6rg\u00fct\u00fc (DS\u00d6), Covid-19’un bug\u00fcne dek ortaya \u00e7\u0131kan mutasyonlar\u0131 i\u00e7inde 4’\u00fcn\u00fc “endi\u015fe verici”, 8’ini “izlenmesi gereken” varyant olarak tan\u0131mlad\u0131.<\/p>\n
\u00d6rg\u00fct, “Endi\u015fe Verici Varyant” (VOC) olarak tan\u0131mlad\u0131\u011f\u0131 mutasyonlar\u0131n, “vir\u00fcs\u00fcn bula\u015f\u0131c\u0131l\u0131\u011f\u0131n\u0131 ve yay\u0131lma riskini art\u0131rabildi\u011fi, \u00f6ld\u00fcr\u00fcc\u00fcl\u00fc\u011f\u00fcn\u00fc veya hastal\u0131k belirtilerini de\u011fi\u015ftirebildi\u011fi, \u00f6nleme ve kontrol tedbirlerinin etkinli\u011fini azaltabildi\u011fi” uyar\u0131s\u0131n\u0131 yapt\u0131.<\/p>\n
\u00d6te yandan “\u0130zlenmesi Gereken Varyant” (VOI) olarak adland\u0131r\u0131lan di\u011fer 8 varyant\u0131n ise “1’den \u00e7ok ki\u015fiye bula\u015fma, salg\u0131n \u00f6bekleri olu\u015fturma gibi topluluk i\u00e7i yay\u0131lma \u00f6zellikleri g\u00f6sterdi\u011fi, birden \u00e7ok \u00fclkede g\u00f6r\u00fcld\u00fc\u011f\u00fc ve endi\u015fe verici varyanta d\u00f6n\u00fc\u015f\u00fcp d\u00f6n\u00fc\u015fmeyece\u011finin izlenmesi gerekti\u011fi” belirtildi.<\/p>\n
Covid-19’un mutasyonlar\u0131n\u0131 Ocak 2020’den bu yana takip eden DS\u00d6, 31 May\u0131s’ta ald\u0131\u011f\u0131 kararla, harf ve rakamlarla belirtilen adlar\u0131 d\u0131\u015f\u0131nda, ilk kez ortaya \u00e7\u0131kt\u0131\u011f\u0131 \u00fclkelerle an\u0131lan varyantlar\u0131n Yunan alfabesindeki harflerle adland\u0131r\u0131lmas\u0131na karar verdi.<\/p>\n
“Endi\u015fe Verici Varyant” olarak belirlenen 4 varyanta Alfa, Beta, Gamma ve Delta; “\u0130zlenmesi Gereken Varyant” olarak kategorize edilen 8 varyanta ise Epsilon (2 varyant), Zeta, Eta, Teta, Iota, Kappa ve Lambda adlar\u0131 verildi.<\/p>\n
Bilim insanlar\u0131, Covid-19 vir\u00fcs\u00fcn\u00fcn yap\u0131s\u0131nda 4 binden fazla mutasyon tespit etti.<\/h4>\n
VOC ve VOI olarak s\u0131n\u0131fland\u0131r\u0131lan varyantlar\u0131n b\u00fcy\u00fck b\u00f6l\u00fcm\u00fc, vir\u00fcs\u00fcn insan h\u00fccrelerine tutunmas\u0131n\u0131 sa\u011flayan “diken proteinde” meydana gelen de\u011fi\u015fimlerden kaynaklan\u0131yor.<\/p>\n
Alfa varyant\u0131: B.1.1.7<\/h4>\n
\u0130lk kez Eyl\u00fcl 2020’de \u0130ngiltere’de tespit edilen “B.1.1.7”, daha sonra verilen isimle “Alpha” varyant\u0131, DS\u00d6’n\u00fcn “endi\u015fe verici varyant” olarak tan\u0131mlad\u0131\u011f\u0131 ilk Covid-19 mutasyonu oldu.<\/p>\n
Londra Hijyen ve Tropikal T\u0131p Fak\u00fcltesine (LSHTM) ba\u011fl\u0131 Bula\u015f\u0131c\u0131 Hastal\u0131klar\u0131n Matematik Modellemesi Merkezince yap\u0131lan ara\u015ft\u0131rmada, \u0130ngiltere’de incelenen \u00f6rneklerde varyant\u0131n Covid-19’un yabani tipine (do\u011fal fenotipine) g\u00f6re y\u00fczde 43 ila 90 daha bula\u015f\u0131c\u0131 oldu\u011fu belirlendi.<\/p>\n
Bula\u015f\u0131c\u0131l\u0131k \u00f6zelli\u011finde benzer bir art\u0131\u015f Danimarka, \u0130svi\u00e7re ve ABD’de yap\u0131lan \u00e7al\u0131\u015fmalarda da g\u00f6zlendi.<\/p>\n
\u00d6te yandan varyant\u0131n daha y\u00fcksek \u00f6l\u00fcm oran\u0131na yol a\u00e7t\u0131\u011f\u0131na dair farkl\u0131 bulgular ortaya \u00e7\u0131kt\u0131. Alfa varyant\u0131, \u0130ngiltere’de g\u00f6r\u00fclen \u00f6nceki Kovid-19 tiplerine k\u0131yasla LSHTM’ye g\u00f6re y\u00fczde 71, Exeter \u00dcniversitesine g\u00f6re y\u00fczde 70, \u0130ngiltere Halk Sa\u011fl\u0131\u011f\u0131 Kurumuna g\u00f6re y\u00fczde 65 ve Imperial College London’a g\u00f6re y\u00fczde 36 daha fazla \u00f6l\u00fcme yol a\u00e7t\u0131.<\/p>\n
Ancak uzmanlar, s\u00f6z konusu bulgular\u0131n s\u0131n\u0131rl\u0131 say\u0131daki numunenin incelenmesiyle elde edildi\u011fine dikkati \u00e7ekerek n\u00fcfusun genelinde \u00f6ld\u00fcr\u00fcc\u00fcl\u00fc\u011f\u00fcn artt\u0131\u011f\u0131na dair bir sonuca var\u0131lamayaca\u011f\u0131n\u0131 vurgulad\u0131.<\/p>\n
\u0130ngiltere’de 2020 sonbahar\u0131 boyunca yay\u0131larak hakim Kovid-19 tipi haline gelmesiyle k\u0131\u015f aylar\u0131nda vaka say\u0131lar\u0131nda belirgin bir art\u0131\u015f g\u00f6r\u00fclm\u00fc\u015ft\u00fc.<\/p>\n
\u0130ngiliz h\u00fck\u00fcmeti, 4 Ocak’ta \u00fclke genelinde yeniden soka\u011fa \u00e7\u0131kma k\u0131s\u0131tlamalar\u0131 ve karantina tedbirleri uygulamak zorunda kalm\u0131\u015ft\u0131.<\/p>\n
Beta varyant\u0131: B.1.351<\/h4>\n
“B.1.351” ad\u0131n\u0131 ta\u015f\u0131yan Beta varyant\u0131, ilk kez Ekim 2020’de G\u00fcney Afrika’da Nelson Mandela K\u00f6rfezi \u00e7evresindeki yerle\u015fim tespit edildi. May\u0131s 2020’de mutasyona u\u011frad\u0131\u011f\u0131 san\u0131lan “Beta” varyant\u0131n\u0131n, DS\u00d6’n\u00fcn “Endi\u015fe Verici Varyant” olarak tan\u0131mlad\u0131\u011f\u0131 Kovid-19 mutasyonlar\u0131 aras\u0131nda ilk ortaya \u00e7\u0131kan oldu\u011fu tahmin ediliyor.<\/p>\n
Daha \u00f6nce herhangi akut hastal\u0131k ge\u00e7mi\u015fi olmayan gen\u00e7 bireyler aras\u0131nda daha fazla yay\u0131ld\u0131\u011f\u0131 g\u00f6zlenen varyant\u0131n, Kovid-19’un yabani tipine k\u0131yasla bu ya\u015f grubunda daha fazla ciddi hastal\u0131k riski ortaya \u00e7\u0131kard\u0131\u011f\u0131 bildirildi.<\/p>\n
Varyant\u0131n yay\u0131lmas\u0131n\u0131n G\u00fcney Afrika’da 2020 sonbahar\u0131ndan bu y\u0131l\u0131n ba\u015f\u0131na kadar g\u00f6r\u00fclen vaka art\u0131\u015f\u0131nda etkili oldu\u011fu d\u00fc\u015f\u00fcn\u00fcl\u00fcyor.<\/p>\n
Alpha varyant\u0131 ile benzerlikler ta\u015f\u0131yan Beta varyant\u0131n\u0131n \u00e7ivi proteinde ilave mutasyonlar yaratmas\u0131, vir\u00fcs\u00fcn bula\u015f\u0131c\u0131l\u0131\u011f\u0131n\u0131n artmas\u0131 yan\u0131nda a\u015f\u0131lara kar\u015f\u0131 diren\u00e7 geli\u015ftirebilece\u011fine dair kayg\u0131lara yol a\u00e7t\u0131.<\/p>\n
A\u015f\u0131 \u00fcreticileri Johnson&Johnson, Pfizer-Biontech, AstraZeneca-Oxford, Sinopharm ve Moderna, varyant\u0131n Kovid-19 a\u015f\u0131lar\u0131n\u0131n koruyuculu\u011funu azaltt\u0131\u011f\u0131n\u0131, antikorlara kar\u015f\u0131 diren\u00e7 geli\u015ftirdi\u011fini bildirdi.<\/p>\n
Gamma varyant\u0131: P.1<\/h4>\n
\u0130lk kez Ocak 2020’de Japonya’da Brezilya’dan seyahat eden yolcularda tespit edilen, daha sonra “Gamma” olarak adland\u0131r\u0131lan “P.1” varyant\u0131 da DS\u00d6 taraf\u0131ndan “Endi\u015fe Verici Varyant” olarak nitelenen Covid-19 mutasyonlar\u0131 aras\u0131nda yer ald\u0131.<\/p>\n
Varyant, vir\u00fcs\u00fcn aminoasitlerinde 17 de\u011fi\u015fim yaratt\u0131\u011f\u0131 biliniyor. Bunlar\u0131n 10’u vir\u00fcs\u00fcn insan v\u00fccuduna tutunmas\u0131n\u0131 sa\u011flayan \u00e7ivi proteini etkiliyor.<\/p>\n
Varyant\u0131n bu y\u0131l\u0131n ba\u015f\u0131nda Brezilya’n\u0131n Amazonas eyaletinin ba\u015fkenti Manaus’daki ani vaka art\u0131\u015f\u0131nda etkili oldu\u011fu tahmin ediliyor.<\/p>\n
Ekim 2020’de yap\u0131lan kan tahlili ara\u015ft\u0131rmas\u0131nda, kent sakinlerinin y\u00fczde 76’s\u0131nda insan v\u00fccudunun Covid-19’a kar\u015f\u0131 geli\u015ftirdi\u011fi antikorlara rastland\u0131\u011f\u0131, bunun “kitlesel ba\u011f\u0131\u015f\u0131kl\u0131\u011fa” i\u015faret eden y\u00fczde 67 oran\u0131n\u0131n \u00fczerinde oldu\u011fu belirlenmi\u015fti.<\/p>\n
Ancak kentte Ocak 2021’de yeni bir salg\u0131n dalgas\u0131n\u0131n ortaya \u00e7\u0131kmas\u0131, vir\u00fcsteki de\u011fi\u015fimin v\u00fccudun yabani tipe kar\u015f\u0131 geli\u015ftirdi\u011fi do\u011fal antikor korumas\u0131n\u0131 etkisiz k\u0131ld\u0131\u011f\u0131, dolay\u0131s\u0131yla a\u015f\u0131lara da diren\u00e7 geli\u015ftirebilece\u011fi endi\u015fesine yol a\u00e7t\u0131.<\/p>\n
Delta varyant\u0131: B.1.617.2<\/h4>\n
\u0130lk kez Ekim 2020’de Hindistan’da tespit edilen ve “\u00e7ift mutant” ad\u0131 verilen “B.1.617.2” de DS\u00d6 taraf\u0131ndan “endi\u015fe verici varyant” olarak niteledi\u011fi son Kovid-19 mutasyonu oldu.<\/p>\n
Vir\u00fcs\u00fcn \u00e7ivi proteininde bula\u015f\u0131c\u0131l\u0131\u011f\u0131 ve antikor direncini etkileyebilecek mutasyonlara yol a\u00e7an Delta varyant\u0131n\u0131n, Hindistan’da martta ba\u015flayan ve g\u00fcnl\u00fck vaka say\u0131lar\u0131n\u0131n 400 bine kadar \u00e7\u0131kt\u0131\u011f\u0131 ikinci salg\u0131n dalgas\u0131n\u0131n sorumlusu oldu\u011fu tahmin ediliyor.<\/p>\n
\u0130ngiltere Halk Sa\u011fl\u0131\u011f\u0131 Kurumu, may\u0131sta yapt\u0131\u011f\u0131 de\u011ferlendirmede, Delta varyant\u0131n\u0131n yay\u0131lma h\u0131z\u0131n\u0131n Alfa varyant\u0131na g\u00f6re y\u00fczde 51-67 daha fazla oldu\u011fu uyar\u0131s\u0131nda bulunmu\u015ftu.<\/p>\n
DS\u00d6, 19 Haziran’da yapt\u0131\u011f\u0131 a\u00e7\u0131klamada, bula\u015f\u0131c\u0131 \u00f6zelli\u011fi y\u00fcksek Delta varyant\u0131n\u0131n d\u00fcnya genelinde bask\u0131n t\u00fcr haline gelmesinin beklendi\u011fini bildirmi\u015fti.<\/p>\n
Ba\u015f a\u011fr\u0131s\u0131, bo\u011fazda kuruluk, burun ak\u0131nt\u0131s\u0131 ve ate\u015f gibi grip benzeri hastal\u0131k belirtilerine yol a\u00e7an Delta varyant\u0131, Covid-19’un \u00f6nceki tiplerinde g\u00f6r\u00fclen \u00f6ks\u00fcr\u00fck, solunum stresi, s\u0131rt a\u011fr\u0131lar\u0131 gibi zat\u00fcrre, so\u011fuk alg\u0131nl\u0131\u011f\u0131 t\u00fcr\u00fc hastal\u0131k tablosundan farkl\u0131la\u015f\u0131yor.<\/p>\n
Delta varyant\u0131n\u0131n a\u015f\u0131lara kar\u015f\u0131 da belirli d\u00fczeyde diren\u00e7 geli\u015ftirdi\u011fi saptand\u0131.<\/h4>\n
Hindistan T\u0131bbi Ara\u015ft\u0131rma Konseyi (ICMR), Bharat Biotech \u015firketinin Kovid-19’un yabani tipi ile geli\u015ftirdi\u011fi inaktif a\u015f\u0131n\u0131n varyantlara kar\u015f\u0131 etkisine dair yay\u0131mlad\u0131\u011f\u0131 ara\u015ft\u0131rmada, a\u015f\u0131n\u0131n B.1.617 ailesindeki mutasyonlar\u0131 etkisiz hale getirmekte ba\u015far\u0131l\u0131 oldu\u011funu fakat bunu daha d\u00fc\u015f\u00fck etkinlikle yapabildi\u011fini ortaya koydu.<\/p>\n
\u0130ngiltere Halk Sa\u011fl\u0131\u011f\u0131 Kurumu da yapt\u0131\u011f\u0131 ara\u015ft\u0131rmada, Pfizer-Biontech ve AstraZeneca-Oxford a\u015f\u0131lar\u0131n\u0131n Delta varyant\u0131na kar\u015f\u0131 ilk dozda y\u00fczde 33, ikinci dozdan sonra Pfizer-Biontech’in y\u00fczde 88, AstraZeneca-Oxford ise y\u00fczde 60 etkili oldu\u011funu belirledi.<\/p>\n
Daha \u00f6nce yap\u0131lan klinik denemelerde, her iki a\u015f\u0131 da Kovid-19 yabani tipine kar\u015f\u0131 y\u00fczde 90’\u0131n \u00fczerinde ba\u015far\u0131 sa\u011flam\u0131\u015ft\u0131.<\/p>\n
“Delta art\u0131” varyant\u0131<\/h4>\n
Hindistan Sa\u011fl\u0131k Bakanl\u0131\u011f\u0131, Delta varyant\u0131n\u0131n ilk kez nisanda ortaya \u00e7\u0131kan bir t\u00fcrev mutasyonunun “endi\u015fe verici varyant” olarak s\u0131n\u0131fland\u0131r\u0131ld\u0131\u011f\u0131n\u0131 duyurdu.<\/p>\n
“AY.1” olarak adland\u0131r\u0131lan ilave mutasyonun vir\u00fcs\u00fcn daha kolay yay\u0131lmas\u0131na, akci\u011fer h\u00fccrelerine daha kolay ba\u011flanmas\u0131na yol a\u00e7t\u0131\u011f\u0131 ve antikor tedavisine direnci art\u0131rd\u0131\u011f\u0131 belirtildi.<\/p>\n
Delta Plus varyant\u0131, Hindistan\u2019\u0131n 3 eyaletinde yakla\u015f\u0131k 40 ki\u015fide tespit edilirken; ABD, \u0130ngiltere, Portekiz, \u0130svi\u00e7re, Japonya, Polonya, Nepal, Rusya ve \u00c7in’in oldu\u011fu 9 \u00fclkeye daha yay\u0131ld\u0131.<\/p>\n
Bilim insanlar\u0131, yeni mutasyonun “Endi\u015fe Verici Varyant” olarak de\u011ferlendirmek i\u00e7in hen\u00fcz yeterli verinin bulunmad\u0131\u011f\u0131n\u0131n alt\u0131n\u0131 \u00e7iziyor.<\/p>\n
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