The COVID-19 pandemic has circulated again recently in Europe and America, with the number of new confirmed cases hitting new highs in countries represented by the UK and the U.S., which has objectively put forward higher requirements for pandemic prevention and control. Urgently in demand, the development of COVID-19 vaccines has been accelerated, and many vaccines have been approved to be vaccinated worldwide. This is expected to relieve the current anti-pandemic pressure and reverse the pandemic to some extent.
R&D progress of COVID-19 vaccines in the world
According to the public information at present, more than 40 COVID-19 vaccines have entered the clinical stage worldwide, of which 17 have entered/completed phase III clinical trials, 8 are in phase II clinical trials, and 18 are in phase I/II clinical trials.
Source: Organized according to public data
Depending on the technical route, the current COVID-19 vaccine varieties in the world include inactivated virus vaccines, adenovirus-vectored vaccines, mRNA-based vaccines, and protein subunit vaccines. Each technical route has advantages and disadvantages: inactivated virus vaccines have the simplest process, however, the immunizing potency is relatively low; adenovirus-vectored vaccines are well tolerated while the anti-adenovirus antibodies in some people can cause the vaccines to fail; mRNA vaccines can be produced fastest, although they are easy to be degraded.
An overview of vaccines approved for marketing worldwide
A total of six COVID-19 vaccines have been approved for marketing worldwide by Jan. 12, 2021, separately, BNT162b2 and mRNA-1273 under the Emergency Use Authorization (EUA) in the U.S., AZD1222 under the EUA in the UK, an inactivated COVID-19 vaccine conditionally marketed by Sinopharm CNBG in China, an inactivated vaccine from India under the EUA in India, and “Sputnik V” approved for marketing in Russia.
The entire development process of a vaccine normally takes 8 to 10 years, with a statistical success rate of only about 20%. According to public data, only six vaccines have been successfully developed and marketed in contrast to 44 newly discovered infectious disease pathogens in the past 50 years, with a success rate of less than 14%. However, the severe global situation of the COVID-19 pandemic since 2020 has prompted the development and approval of COVID-19 vaccines to be greatly accelerated. The COVID-19 vaccines approved for use in China, the U.S., and the UK are all marketed conditionally or under the EUA, and the subsequent monitoring data still need to be taken into consideration for approval.
It should be noted that no valid clinical trial data have been made available for the inactivated vaccine approved under the EUA in India and the “Sputnik V” approved for marketing in Russia, thus their efficacy is doubtful.
Inactivated COVID-19 Vaccine of Sinopharm CNBG
An inactivated virus vaccine is a vaccine that can cause the virus to lose its infectivity and replication ability through physical or chemical treatment while retain the virus’s activity to trigger an immune response in humans. Inactivated vaccines are vaccine products with prototype viruses entirely inactivated, retain almost all the antigens and epitopes of the viruses, and can target the conserved epitopes of viruses to reduce the possibility of virus escape.
The inactivated COVID-19 vaccine of Sinopharm CNBG received approval from the National Medical Products Administration of China (NMPA) at the end of Dec. 2020 for conditional marketing. According to the interim analysis data results of phase III clinical trial, the vaccine had good safety after vaccination, and after two injections of the immunization procedure, all vaccine recipients had high-titer antibodies, with a neutralizing antibody-positive conversion rate of 99.52%. The protective efficacy of the vaccine against the disease caused by the novel coronavirus infection (COVID-1...
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