Pembangunan vaksin untuk COVID-19 adalah keutamaan global. Dalam artikel ini, penulis telah menyemak dan menilai penyelidikan dan pembangunan serta status semasa pembangunan vaksin.
Covid-19 penyakit, yang disebabkan oleh virus SARS-CoV-2, telah meningkat secara berterusan dalam beberapa bulan kebelakangan ini di seluruh dunia tanpa penghujungnya. Sehingga kini, tidak ada vaksin diluluskan untuk menyembuhkan penyakit yang melemahkan ini penyakit yang telah menjangkiti sekitar 2 juta orang di seluruh dunia dan menyebabkan kematian kira-kira 120,000 daripada mereka (1), angka 6%. Kadar kematian 6% ini adalah purata di seluruh dunia, dengan Kesatuan Eropah mempunyai kadar kematian sekitar 10% manakala seluruh dunia mempunyai kadar kematian sekitar 3%. Terdapat juga pemulihan sekitar 450,000 orang, angka sekitar 23%.
Syarikat farmasi dan bioteknologi bersama universiti dan institut penyelidikan di seluruh dunia sedang berusaha dengan penuh semangat untuk membangunkan avaccine against COVID-19 that could become the saviour of people and prevent them for getting the disease. This article will focus on the concept of vaccine development for viruses, the types (category) of vaksin being developed for COVID-19 by numerous companies, institutes and consortiums around the world who are engaged in its research and development and its present status with emphasis on vaccine candidates that have already entered clinical trials.(1).
Pembangunan vaksin untuk virus melibatkan penyediaan biologi molekul virus yang terdiri daripada virus hidup yang dilemahkan, virus tidak aktif, zarah virus kosong atau peptida virus dan protein (s) sahaja atau gabungan, yang sekali disuntik ke dalam individu yang sihat, mencetuskan sistem imunnya untuk menghasilkan antibodi terhadap molekul virus, dengan itu melindungi individu apabila jangkitan sebenar berlaku. Molekul dan protein virus ini yang bertindak sebagai antigen, sama ada boleh dijana di luar (dalam makmal) atau dihasilkan (dinyatakan) di dalam individu (tuan rumah) untuk menjana tindak balas imun. Kemajuan teknologi dalam bidang bioteknologi dalam dekad yang lalu atau lebih telah memainkan peranan penting dalam pembangunan vaksin juga, menghasilkan pendekatan baru untuk pengeluaran antigen virus di dalam atau di luar individu hos, yang telah menyumbang kepada keselamatan vaksin, kestabilan dan kemudahan pembuatan berskala besar.
Jenis-jenis vaksin under development for COVID-19 fall into three broad different categories based on the nature of technology platforms to generate viral antigens (2). The first category comprises of using the live attenuated vaccine (that involves weakening the virulence of SARS-CoV-2 virus) or inactivated virus (in which the inactivation is performed using chemical means) and injecting it in the host to develop an immune response. This category represent the way in which vaksin were made conventionally. The second category in vogue focuses on the production (expression) of viral proteins inside the host (humans) by use of nucleic acids (plasmid DNA and mRNA) and viral vectors (replicating and non-replicating) containing viral genes. These nucleic acids and viral vectors use cellular machinery for the expression of viral proteins within the host upon injection, thereby triggering an immune response. The third category involves development of empty (without genome) viral like particles (VLPs) expressing viral proteins on their surface, use of synthetic peptides (selected parts of viral proteins) and recombinant production of viral proteins as antigens in various expression systems at a large scale outside the human host, and then using them as vaccine candidates alone, or in combination.
As of April 10th 2020, a total of 69 companies, research institutes, universities and/or a consortium of the above (3, 4) are actively engaged at an unparalleled speed in a race against time for the development of COVID-19 vaccine. These companies can be divided into either of the three categories mentioned above based on the technology they are using for COVID-19 vaccine development. Seven of these companies are exploiting the way vaksin are manufactured by the first category and the remaining 62 companies are almost equally divided (30 in the second category which uses plasmid DNA, RNA and replicating and non-replicating viral vectors while 32 in the third category which uses VLPs, peptides and recombinant viral proteins) in terms of the technologies used for vaccine manufacturing for COVID-19. Most of these companies are in exploratory or pre-clinical stages of research and development. However, six of these companies have advanced their candidate vaksin into clinical trials which are listed in Table I (information sourced from references 2-6). All these vaksin fall into the second category.
Pembangunan vaksin untuk COVID-19 berdasarkan platform teknologi yang digunakan adalah masing-masing 10% untuk kategori pertama dan 43.5% untuk kategori dua dan 46.5% untuk kategori tiga (Rajah 1). Berdasarkan lokasi geografi, Amerika Utara (AS dan Kanada) menerajui pembangunan vaksin COVID-19 dengan peratusan tertinggi syarikat (40.5%) diikuti oleh Eropah (27.5%), Asia dan Australia (19%) dan China (13%). Rujuk Rajah 2.
Rajah 1. Kategori pembangunan vaksin COVID-19
Table I. COVID-19 vaksin dalam ujian klinikal
Rajah 2. Taburan geografi syarikat yang terlibat dalam penyelidikan dan pembangunan vaksin COVID-19.
The majority use of categories 2 and 3 in vaccine development for COVID-19 suggests the exploitation of modern state of the art technologies that have led to the ease of manufacturing and might contribute to the safety, stability and effectiveness of vaccine preparations. It is sincerely hoped that the current vaksin in clinical trials and the ones that follow would result in an effective vaccine candidate that can be fast tracked for approval by the regulatory authorities for vaccinating the human population, thereby preventing them from contracting the COVID-19 disease, and overcoming the misery that has been caused by this debilitating disease.
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Rujukan:
1. Worldometer 2020. PANDEMIK CORONAVIRUS COVID-19. Kemas kini terakhir: 14 April 2020, 08:02 GMT. Boleh didapati dalam talian di https://www.worldometers.info/coronavirus/ Diakses pada 13 April 2020.
2. Thanh Le T., Andreadakis, Z., et al 2020. Landskap pembangunan vaksin COVID-19. Diterbitkan pada 09 April 2020. Nature Reviews Drug Discovery DOI: http://doi.org/10.1038/d41573-020-00073-5
3. Institut Milken, 2020. Rawatan COVID-19 dan Penjejak Vaksin. Boleh didapati dalam talian di https://milkeninstitute.org/sites/default/files/2020-03/Covid19%20Tracker_WEB.pdf Diakses pada 13 April 2020.
4. WHO, 2020. DRAFT landscape of COVID-19 candidate vaksin – 20 March 2020. Available online at https://www.who.int/blueprint/priority-diseases/key-action/novel-coronavirus-landscape-ncov.pdf?ua=1 Diakses pada 13 April 2020.
5. Fokus Kawal Selia, 2020. Penjejak Vaksin COVID-19. Boleh didapati dalam talian di https://www.raps.org/news-and-articles/news-articles/2020/3/covid-19-vaccine-tracker Diakses pada 13 April 2020.
6. USNLM 2020. Jejak Klinikal COVID-19 Tersedia dalam talian di https://www.clinicaltrials.gov/ct2/results?cond=COVID-19 Diakses pada 13 April 2020.
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