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Objavom genetičke sekvencije virusa SARS-CoV-2 mnogobrojne tvrtke krenule su u razvoj cjepiva. Protein šiljka i njegova receptor-vezujuća domena, na temelju svoje imunogeničnosti, nametnuli su se kao glavne antigenske mete u razvoju cjepiva. Velik je broj strategija koje su različiti proizvođači odabrali na polju dostave odabranog antigena u stanice. Tradicionalni pristup uključuje cjepiva s inaktiviranim te oslabljenim virusom, a noviji pristup cjepiva temeljena na virusnoj podjedinici, na čestici nalik virusnoj, vektorska cjepiva, DNA te RNA cjepiva. Znanstvenoj zajednici najzanimljivija su RNA cjepiva jer su u pandemiji COVID-19, uz vektorska cjepiva, najbrže autorizirana za tržište, kao i zbog testirane sigurnosti i učinkovitosti, koja je na veoma visokoj razini. U razvoju cjepiva treba razmotriti i upotrebu adjuvanata koji povećavaju i moduliraju imunogeničnost cjepiva. Može biti riječ o agensima dodanim izvana, kao što su aluminijeve soli, ali često i same sastavnice cjepiva posjeduju imunostimulatorna svojstva. Zaključno s 12.8.2021., četiri su COVID-19 cjepiva licencirana za upotrebu u EU. U razdoblju visokog postotka preboljelih i cijepljenih dolazi do pojave novih varijanti virusa koje su evolucijski favorizirane jer izbjegavaju stečeni imunitet populacije. Stoga, uz razvoj cjepiva optimiziranih za zaštitu od prevalentnih varijanti, morat će se poraditi i na modelima koji bi mogli predvidjeti pojavu novih virusnih varijanti. After the publication of the genetic sequence of the SARS-CoV-2 virus, numerous companies initiated vaccine development. Spike protein and its receptor-binding domain have been established as the best antigen targets for vaccine development, based on their immunogenicity. There is plethora of strategies selected by various producers, in terms of antigen delivery to the cells. Traditional approach vaccines include attenuated and inactivated virus vaccines while virus subunit vaccines, virus-like particle and viral-vectored vaccines, DNA and RNA vaccines are of a more modern approach. RNA vaccines are of most interest to the scientific community because, during COVID-19 pandemic, they have been authorised for the market in the shortest time, along with viral-vectored vaccines. Moreover, COVID-19 RNA vaccines' safety and efficacy have been proved to be on a remarkable level, too. As of August 12, 2021., four vaccines have been licensed for use in the EU. Use of adjuvants, which increase and modulate the vaccine immunogenicity, should also be considered when developing a vaccine. Adjuvant compounds can be added extrinsically, e.g. aluminium salts, but a vaccine component itself often has immunostimulatory properties. In conditions of high percentage of convalescent and vaccinated people, new virus variants emerge, which are evolutionary favoured since they escape the acquired immunity of a population. Hence, besides optimising vaccines for protection against prevalent virus variants, models that could predict emergence of new ones should be developed, as well. |
