CINXE.COM

<!DOCTYPE html><html lang="en-US"><head><title>Just a moment...</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=Edge"><meta name="robots" content="noindex,nofollow"><meta name="viewport" content="width=device-width,initial-scale=1"><style>*{box-sizing:border-box;margin:0;padding:0}html{line-height:1.15;-webkit-text-size-adjust:100%;color:#313131;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,Noto Sans,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol,Noto Color Emoji}body{display:flex;flex-direction:column;height:100vh;min-height:100vh}.main-content{margin:8rem auto;max-width:60rem;padding-left:1.5rem}@media (width <= 720px){.main-content{margin-top:4rem}}.h2{font-size:1.5rem;font-weight:500;line-height:2.25rem}@media (width <= 720px){.h2{font-size:1.25rem;line-height:1.5rem}}#challenge-error-text{background-image:url(data:image/svg+xml;base64,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);background-repeat:no-repeat;background-size:contain;padding-left:34px}@media (prefers-color-scheme:dark){body{background-color:#222;color:#d9d9d9}}</style><meta http-equiv="refresh" content="120"></head><body class="no-js"><div class="main-wrapper" role="main"><div class="main-content"><noscript><div class="h2"><span id="challenge-error-text">Enable JavaScript and cookies to continue</span></div></noscript></div></div><script>(function(){window._cf_chl_opt={cvId: '3',cZone: "publications.waset.org",cType: 'non-interactive',cRay: '9133fc9d9c5ffce3',cH: 'CBoVVfwZM3I7IYFOfI1HukCAmqYCnqMYIwIJHT40m1o-1739776532-1.2.1.1-rUDqI980mBlhCEU5OAeXP0493fC._nSQcb8YWR9nt_EBJTHBLuC9fkbR0HihxPWJ',cUPMDTk: "\/abstracts\/search?q=covid%2019&__cf_chl_tk=LPdqLnyUgEpfM4DhDr2Xhz363ykSv_X9p5rHx2Y6ttk-1739776532-1.0.1.1-2BJW7YRWu.UT_Pv_MC4NpB7vSh.SlwtqiencFWgkA8I",cFPWv: 'b',cITimeS: '1739776532',cTTimeMs: '1000',cMTimeMs: '120000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/abstracts\/search?q=covid%2019&__cf_chl_f_tk=LPdqLnyUgEpfM4DhDr2Xhz363ykSv_X9p5rHx2Y6ttk-1739776532-1.0.1.1-2BJW7YRWu.UT_Pv_MC4NpB7vSh.SlwtqiencFWgkA8I",md: "eTcgGAn.vgMItGXeVsrVjKr6zcxaomXWr1md_w9k2TM-1739776532-1.2.1.1-nTm.nhzgCmNA3Jgd1nOL4.AwFsygQCYffEhee7WbbgVjxQdPkRNCtCvrNYJKPtTYbBkEi8LA4HYHA4x5IBsBIsGOsrnH9D.5djGZhfd.aQYICs1kfttdHWnjw5aKfsyp5tj8xa7hvFwRF43acPp5cf4GX1pjVITMWLhqStZuWtk.IYrGGd9UPkaHp1iLI1VLeWsEQYjcms0pUR2DZSeiPF93VHS805jvuBebQhfH0oXgph1a.nIXYuP.7wYoBEOdVABtiFJ9p6QZ304Q4nmCrqIqIIJaPOBEtKQz9wM5OhQQqIXYFNxnHIkOPuc3fRT7gXmcw0eTBC72Jz520Yy7bef9Is5K3uUSgFzrs3lxsJ.jCiDfn5TkpujJL2dYQRe8JUL1VCZi9tETSqER5IA_8SF.sei6hVhIm3NbDUe8lJ8Kcuf2yMmIXAkUaUvo1iIGHBH36Kyq9YhXtiDuhLyYqQr0d3JFsDyntChufbgODrNp8H6jV8XOexkNdDMg9CBC_rQLbbJRgxJEQdcDnkre.AM84vqxpfqyKk7wfkvC1q._B0JajOIjHnRV9eJ7SxZALTQ1F7VIIEwfKMkv85HYL.46G6YGdfUxt3gteIr8uaB_.b1RfenTfkliwkGZt_hr8lfh6UWucilp6plQb6cyO41D5hCDHoDjL66nkneSXG3XEur_0Sn04BNHSKrX2_n1rFQjviayjGe60KEQwPiV1qQeivehq2VSY4RCq3gqEQnXCBq10n3W2XwAS8WbRx5HbvMUNuuTJ95jXfVVMdMQeLpr1_9L0oTdWLyqnVmtx09pwNdi4pmgAOyArWllzP738jWhqcytQs7WuxA_lEw8NYe2zswf1qcKvls1nxKatEO.Ef.RPE9YPR.5EoA7FROMrTY03muLYHsIomSFJXZftqVa4VDWEdaXGqZpOOrBTxDMBZL.IiWdHHkWu.2JSBdMXr63MZ1kVWp882.XJnX71iOcTnBSUqsvAtKPp425Ha07GOnma_UZ9SqqAr4entY7YX7xENttr26S73zKZ5czd2DQl.2SiGd6r8YjtMOGtIoWf_B1iepXh1LeetyOU_e_Ast.ymHPiilqhDC6bnXjWsAJ6uzD4KmHM0nAQerJFQVoxvGjf3HlM3nWrTzO7hNWTGvgRiQGwJparneoL4irN_XsoPvaibQvtNGE8MCsJ6gIMGAER8jnGKKh_gK2ulLZRj9nmcNH_.OKvkHADx8joNBp0axeQdLkPQJo3pWSpJjp4RJ2vhIAcB72L7sCvd.PSCqBQ_fweFahagzXAh8_1dIKoD16.sH6.D3rHgOZzH3xanS0tRpt.ZBNLuHTZeys8m94kPLs.0.cxxj.XW7ZOK7lcBwx6.8yia1p4nxog6Yb6IGVuxBK7yKEIaWzk2s.jeT1d0VJaIOAz5sX1Ru2zYzGpfvyA.W.JXn4.OMYrjiKBgvwkLQIz1P8w0_L5Nn8XJ2X.g91cflfCxcoHErkp9NzePy6XF3ULvy2EF.kXdcWEMLu4koaRSlhlb5NqxgUK1HVNeRud9RSwUCN2y3rMb4fCt1NIeL.U4OjLZLuqPvoEwL.CbrbwZ8axEuXbuEq.ms5fRxZy0kO60CmvA.sp8ODNOpZuGEoljOF2bw5S.M.8M5qACnZBTllmYopAAfGi1Smy4HOOFTusJPrK1.6J5SoNYprtYra56bY_bZmk0mhEdD.otQWWwn7QbXV7BJF28QQGI42..ogE1mfPxCSlIALrlQXC77XncS_qvZUlZA2wJYkO4Z9V7hmwg3c_uPrBrQgB5kltowaBcwf8gcgfoiJrWfJitLC72zGBk0xYNZ6K1K3jqSDDuGrPYSubDFNZEQzW3_JXKtEUm1ZZFWDO.zwc7JOQbaZVpakb9t.goXOXOEQSynCSQWGOgNrKkxUpcwELXV6sX_XrdksO6MgDw",mdrd: "Sx9T_y1nuICg.xYCoD9HKUh37ZbcB0NLiMPMYvnFBks-1739776532-1.2.1.1-ZWcnr8ucoTPTiMb9cQuDao7MQvZFqyJFsRvE6ac14XG7nbxpSd4.cYx9t1T33Ik5fK3yb.phvHgGMHOR8REJfRJXUTftDbwLEssBX_xaQpZejBl3xwxLuuPUdHaJmTbfcdo2D.u95izE7NgxJS_8CVkaYuO5uum7qDdJBgCgmZRR6X5R9qdY6HkxEeOyDhqw5wwGATxN6n5VAIgSPpMzar6O8.ZBb1W.VnYj4nCE3in9XOOewXBqPLUuNSGd287pE.PE2zym17GXBAwg8fzfvsNVPWbUiOkKdJNR483i4hRA7GX.cbFN_WJYYvoPsxzo7D86o6eoi8zN5lTlC2FO61OO6Z8rq6leYojQfU7lQAcXjUi7ZqkI852ajNFlxyR3YoSvz_1rIhx8VVOCeznU7BZrX6EgaGzovcDlVnM6FlR8DFlIO0TN5_4LFastyMUcejXCnumrzRI3x.1kAV_8Xy6GxaiAHPFpbo1N3XFdaTnPq0YYNAUsBen2sojPtL3u0eMIlgOXPHsH224bMdPLKx9ArkyK2QyoKDsiWqvqy.jB4J8pnESBHkSUlVZPwSevuCjnUYefB.DmOudhlIiOdHB85ErgRHZUyOQ4MPJgJeUMUryRPbvNzmYsbw3ShGbcTUANBiBSCLa3fnvwjJZMxxA_8s2.Q1xcm8i3_kotKnHkF_8ZzmBujln17TOD5FT74IdiJUjCYrEv96q_nNtQsP1dJ5kQFLNAlLPDM4H_ww3NdquMAJa.GU5ynfjf36udE1.AXEK4NygrNd3eZ2PQLUKFs00.mJiA12e1rEK1dkW6.3Xv3QwKVC.rZbCVW80isqLy89JDLNESYM3dCgYyn4BQwT.kJXAaBVznp8mVmitj_DrhNgxx9fbJ_N9j8zPAU5tRkHO3Hx0pwd4W.OqIFLKXd_jNFZmcii2i45FvfxF34SrBII_3zAmmxiplkP9MxqNW4vNm.AqzYn3bpeGUCKOJTirp7XRb2Y5yfNOn8xbrMkL61cEYA5z4P5YDip0L7yz5mLWbzLioRsZ.SSokEWcAUsrQZZgbHRoeRPTilDg6THy8VfKDngs2i4duaBKq34dNjLfyUOwwtvU54EGVMNVm7gGkxpbT9XM83E0Tzqns0Gv0xzimE1DkZ.8AxfL9WB24IXK7aTomUrSpW9PTnakpETcoef2mGJ6BP8rZTt0HtS6dhE8dnu8C_eznHSddsGC0JuQFhTv.eR0JXdcTEce41fzkcvh0k_ZbPlp9XUQfT6O40GByt14Ube0uonEGYx8mqUh952PlYztn408V4uC_bK4etrdtuo3pOPDJgpwcoeaNll4OLD79beNVKwlViA77KzKjXgfTEKu2ZuTer73T_KfFCE5fn.JJ3PmHgGex0.wNepk1Xh8pZZEygRsq3m3jMFJleGaaHRZI6kjLVaoZc1fPJaztxMIPspnul.Px.sABlRqQfe_DXslQcnTJylzGv2Ldxc94FmAwWShEdSrCH9j9WL6DMv.fF_lnlL57rsXSEnnGdXMXRQTG5OE.1cs6G9YlFIdmHrhmbs1R01RN092c5T1R6US_a8IoOa5sf3O0eS_qR.BX8NSAsaMLpUWc0CoxwMktJnHdIzU_qcDhPYG9sFbhs1bLX5dLdNJSwNXvr.1qHgPSW9b8xNMDbI0Hs5oDtQYL8jKktJEz3gUIclW99XsT.ZyEldUDpNuFpH9oQMWvv89Yh8.jI6TnMjmCIcrX8.qM6.sOTG0oYHJ.jBeQmc7O.7l5VY3o4vZQ.eq1daDzM2o3zVJyb83B2CvvTXEHJwkYSNqsv4x8TbTtCo612aEqvMRzrneaf2rR0TL_s6T35DBtqOkNbmVfe1XAbSoIKmEWI0Bq1RHQ0ywL3ZCWRWigTnTlz45_oYhThGEhkkpRoTy2SR9.is8yLOh8o3w7Fks49aZ4_Gvqal_Q9IK38h29yWWSv_picRDwN3xFbJPCcJThEhQmiX8e"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9133fc9d9c5ffce3';window._cf_chl_opt.cOgUHash = location.hash === '' && location.href.indexOf('#') !== -1 ? '#' : location.hash;window._cf_chl_opt.cOgUQuery = location.search === '' && location.href.slice(0, location.href.length - window._cf_chl_opt.cOgUHash.length).indexOf('?') !== -1 ? '?' : location.search;if (window.history && window.history.replaceState) {var ogU = location.pathname + window._cf_chl_opt.cOgUQuery + window._cf_chl_opt.cOgUHash;history.replaceState(null, null, "\/abstracts\/search?q=covid%2019&__cf_chl_rt_tk=LPdqLnyUgEpfM4DhDr2Xhz363ykSv_X9p5rHx2Y6ttk-1739776532-1.0.1.1-2BJW7YRWu.UT_Pv_MC4NpB7vSh.SlwtqiencFWgkA8I" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>