I-COVID-19: UVavanyo lokugonywa koMhlambi kunye noKhuseleko logonyo

Umhlambi ukugonyeka ngenxa Covid-19 kuthiwa kuphunyezwa xa 67% of labantu is omzimba kwi intsholongwane ngosulelo kunye/okanye ugonyo, ngelixa i-pathogen ihlala ibonakaliswe kakuhle (ingaguqukiyo) kulo lonke usulelo kuluntu oluphawulwe kakuhle. Kwimeko yosulelo lwe-SARS CoV-2, ukufezekiswa kokugonywa komhlambi kulucelomngeni ngenxa yokuvela kwezinto ezintsha ezahlukeneyo ezixhalabisayo (VoC), ezikhokelela ekubeni iVoC ingaphenduli kwizilwa-buhlungu eziveliswa ngokuchasene noxinzelelo lwabazali. Idatha ibonisa ukuba i-Israel inokuba ifumene ukungakhuseleki komhlambi njengoko ifikelele kwi-67.7% yabemi abangakhuselekanga ngelixa i-UKumune Inani labantu lingama-53.9% kwaye elo lase-USA li-50.5%. Ngaphandle kweqondo eliphezulu losulelo eBrazil ekuqaleni, ukugonywa komhlambi akukafikelelwa. Oku kuphakamisa ukuba abantu kufuneka babambelele kumgama wentlalontle, ukuhlamba izandla kunye nokunxiba iimaski kunye nezikhokelo zokuvula kunye nokukhululeka kwezithintelo kufuneka kucingwe ngononophelo ukuthintela nasiphi na esinye isiganeko esiyintlekele ukusuka. Covid-19. 

Ukuze kufikelelwe kwimeko “eqhelekileyo” ihlabathi laliphambiCovid-19, ukukhuseleka komhlambi kufuneka kuphuhliswe phakathi kwabemi okuya kuvumela abantu ukuba baphume kwaye bazulazule ngokukhululekileyo njengangaphambili. Ukugonywa komhlambi kunokufikelelwa ngabantu abosulelwa yintsholongwane ngokwendalo okanye ngokugonya ipesenti ethile yabantu. Makhe sijonge ukuba ugonyo kunye nosulelo ngokudibeneyo lunokukhokelela njani ekungakhuseleni komhlambi kwaye kusibuyisele ebomini ngaphandle kweemaski kunye nokungena ekuhlaleni ebesiphila ngaphambili. 

Ukungafikeleki komzimba^{1, 2} ibhekisa kuqikelelo lokuba bangaphi abantu ekufuneka begonyiwe okanye bosulelwe ukuqinisekisa ukuba intsholongwane ayisasuleleki ebantwini. Oku kuthetha ukuba abasekho abantu abanokuchaphazeleka abanokuthi bafumane usulelo kwaye balusasaze ngakumbi. Nangona ukungakhuseleki komhlambi (P_I, umlinganiselo wabemi abakhuselekanga) unokubalwa ngokusekelwe kwifomula elula yemathematika^{1, 2}, P_I = 1-1/R_o, apho uR_o (“R-naught”) ibonisa inani leemeko zesibini ezibangelwa lusulelo, olukwabizwa ngokuba yinani elisisiseko lokuzala xa usulelo lwenzeka kwi-immunologically naïve. labantu (abemi abangazange bosuleleke okanye bagonywe yintsholongwane). Kwimeko ye-SARS CoV-2, i-R_o kuqikelelwa ukuba bamalunga ne-3, nto leyo ethetha ukuba umntu ngamnye uya kosulela umyinge wabantu abathathu^{3, 4}. Ekufakeni oku kule fomula ingentla sifumana i-P_I inani lika-0.67 elithetha ukuba ukuba i-67% yabemi mhlawumbi yosulelekile kwaye/okanye iye yagonywa, ngoko ukugonywa komhlambi kuthiwa kufikelelwe.  

Ngaba oko kuthetha ukuba amazwe afana no-Israel afumene ukugonywa komhlambi njenge-67.7% (58.2% egonywe ngokupheleleyo kunye ne-9.5% yosulelo) yabemi bakwaSirayeli⁵ abakhuselekanga ngeli lixa amazwe afana ne-UK kunye ne-USA izakufumana ukugonywa komhlambi xa bene-67% yabemi bakhona mhlawumbi bosulelekile kwaye/okanye begonyiwe, ngoku okuku-53.9% (47.3% egonywe ngokupheleleyo kunye ne-6.6% yosulelo) iUK⁶, kunye ne-50.5% (i-40.5% igonywe ngokupheleleyo kunye ne-10% eyasulelekileyo) e-USA⁷?  

Kunzima ukuphendula lo mbuzo kuba ubalo lokugonywa komhlambi (P_I) isekelwe kwiingcamango zokuba i-pathogen ibonakaliswe kakuhle kwaye iyosulela uluntu oluchazwe kakuhle. Ngelishwa, zombini aziyonyani kule meko njengoko le yintsholongwane entsha kwaye abantu abosulelekileyo bahluke kakhulu. Iphinde ibe nzima ngakumbi yinto yokuba kukho iintlobo ezintsha zentsholongwane ye-SARS CoV-2 ezivela kubemi ezinokuthi ziphendule okanye zingasabeli kwisitofu sokugonya ngendlela efanayo nohlobo lokuqala lwentsholongwane oluyilelwe lona isitofu sokugonya. Ngaphezu koko, iintlobo ezintsha zentsholongwane azifani nokuchaphazela onke amazwe. Ngelixa i-UK ubukhulu becala inomahluko we-B.1.1.7, i-Indiya, iSingapore kunye namanye amazwe anokwahluka kwe-B1.617, i-Brazil ine-B.1.351, i-P.1 kunye ne-P.2 eyahlukileyo ngelixa i-Middle East ine-B.1.351 eyahluka ukongeza kwabanye. Ngaba oko kuthetha ukuba abantu abaninzi bosulelwa luhlobo olutsha ngaphandle kokugonyelwa uhlobo lokuqala olutyhala i-R?_o kwinani eliphezulu? I-AR_o yaba-5 bekuya kuthetha ukuba ama-80 ekhulwini abemi afanele akhuseleke ukuze athintele usulelo olungakumbi. Nangona kunjalo, la mazwe (i-Israel, i-UK kunye ne-USA) sele iqalile ukuvula kunye nokunyusa izithintelo ngokusekelwe kwinto yokuba ubuncinane i-50% yabemi bayo igonywe ngokupheleleyo. Ngaba kusekude kakhulu kumatyala ase-UK nase-USA njengo-P_I akafikelelanga nakwi-67% ngokusekwe kubalo olulula nolu qikelelo olukhankanywe ngasentla? U-Israel usenokuzingomb' isifuba ngelithi ufikelele kweli nani. Nangona kunjalo, kuye kwakho ukwanda kwenani lamatyala e-UK kule veki nge-23.3% (xa kuthelekiswa neveki edlulileyo) kunye nokunyuka okuhambelana nokufa.⁶, ngelixa e-USA, kuye kwakho ukuhla kwenani lamatyala ngama-22% kule veki⁷ (xa kuthelekiswa neveki ephelileyo). Idatha kwiinyanga ezimbalwa ezizayo iya kugqiba ukuba isigqibo lala mazwe sokuvula kunye nokunyusa izithintelo sasichanekile okanye akunjalo? 

Ngazo zonke ezi zinto zinxulumene nobunzima bentsholongwane (iintlobo ezahlukeneyo) kunye ne-heterogeneity yabemi, akunakwenzeka ukuqikelela i-P echanekileyo._I inani. Kufanelekile ukukhankanya apha malunga namazinga osulelo eBrazil, elinye lawona mazwe achaphazeleke kakhulu kumanqanaba okuqala pf usulelo lwe-COVID-19. Ngaphandle kwepesenti ephezulu yoqikelelo lwe-seroprevalence (76%)¹¹ eManaus kunye ne-70% ePeru¹², bobabini babona iliza lesibini eloyikekayo. Ngelixa oku ngokuyinxenye kunokubalelwa kukulula kwezithintelo kunye nonyulo oluye lwabanjwa, ezinye izinto ezininzi zinokuba noxanduva olufanayo. Enye inokuba yi-overestimation ye-seroprevalence ebonwe ukuba yi-52.5% ngoJuni 2020. Okwesibini ingaba yinkqubo entsha kunye neyokusuleleka ngakumbi (P.1, P.2, B.1.351, B.1.1.7), nganye ineseti yayo eyodwa yotshintsho olubangela ubunzima obuphezulu besifo. Okwesithathu, ubukho bolu tshintsho bunokukhokelela ekubalekeni impendulo yokuzikhusela komzimba eyenziwe ngokuchasene nohlobo lokuqala.¹².  

Omnye umbuzo malunga nokusebenza kwezitofu zokugonya ezikhoyo ngoku malunga nokhuseleko ezinokunikezela. Kuqikelelwa kumndilili wokuba isitofu sokugonya esisebenzayo ngokumalunga nokhuseleko lokufa ngama-72%⁸ into ethetha ukuba kukho ama-28% amathuba okuba umntu asweleke nasemva kokuba egonywe ngokupheleleyo (emva kokuthatha iidosi ezifunekayo zesitofu sokugonya). Ngokuthe ngqo, iPfizer-BioNTech BNT162b2 yayisebenza ngama-85% emva kwethamo elinye ngelixa ugonyo lwe-Oxford-AstraZeneca ChAdOx1-S lwalusebenza ngama-80% emva kwethamo elinye.⁹. Zombini ezi zitofu ziye zasebenza ngokuchasene nohlobo lwe-B.1.1.7⁹. Enye ingongoma ebalulekileyo ekufuneka uyikhumbule apha kukuba ugonyo aluthethi ukuba awuyi kosulelwa yintsholongwane, oko kuthetha ukuba uya kukhuselwa njengoko kukhankanyiwe ngasentla kwaye uya kukhula nokuba buthathaka okanye akukho zimpawu zesifo. Ngaphaya koko, abukho ubungqina okwangoku bokuba ukhuselo lomzimba olubonelelwa lusulelo kunye/okanye ugonyo oluchasene ne-SARS CoV-2 luhlala ixesha elide okanye akunjalo?¹⁰ Oku kuthetha ukuba kufuneka kubekho ucupho olululo endaweni kwaye nenkqubo yogonyo inokufuna ukwandiswa ukuba oku kunokuba njalo. 

Ukongeza kwimpumelelo ye ukungazinzi komzimba luluntu ngokosulelo nangenxa yogonyo olupheleleyo, abantu abathile basenokuthi bachaphazeleke kwaye babandezeleke zizigulo okanye ukufa okubangelwa yi-COVID-19. Abantu abanjalo banokuchongwa ngokusebenzisa i-Electronic Health Records (EHRs) kwaye banikezela ngononophelo olufanelekileyo lokukhusela njengoko kuchaziwe¹³. 

Ngamafutshane, ukuxela kwangaphambili ukungakhuseleki komhlambi we-SARS CoV-2 ngumceli mngeni ongenakoyiswa ngenxa yemo yenguqu efunyenwe yintsholongwane eyenza ukuba yosuleleke ngakumbi kudityaniswa nabantu abaninzi abosulelekileyo. Kuqikelelwa ukuba kude kube nguR_o isondela okanye ingaphantsi kwe-1 (oko kuthetha ukuzuza ukungakhuseleki komhlambi we-100%), abantu kufuneka baqhubeke nokubambelela kumanyathelo okungenela ekuhlaleni, ukuhlamba izandla nanini na kunokwenzeka kwaye banxibe iimaski esidlangalaleni ukunqanda ukosulelwa sesi sifo. Oku kuthetha ukuba amazwe kufuneka acinge ngokucokisekileyo phambi kokuba athathe isigqibo sokuthoba izithintelo phambi kokuba kufikelelwe kwi-100% yokungakhuseleki komhlambi (kwicala elikhuselekileyo) ukunqanda izehlo eziyingozi ezibangelwa yi-COVID-19.  

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Ucaphulo 

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