VOLUNTARY ANNOUNCEMENT - BIVALENT COVID-19 mRNA VACCINE (SYS6006.32) INCLUDED FOR EMERGENCY USE IN CHINA

Hong Kong Exchanges and Clearing Limited and The Stock Exchange of Hong Kong Limited take no responsibility for the contents of this announcement, make no representation as to its accuracy or completeness and expressly disclaim any liability whatsoever for any loss howsoever arising from or in reliance upon the whole or any part of the contents of this announcement. (Incorpor ated in H ong Kong with limi ted liabi lity) (Stock co de: 1093) VOLUNTARY ANNOUNCEMENT BIVALENT COVID-19 mRNA VACCINE (SYS6006.32) INCLUDED FOR EMERGENCY USE IN CHINA The board of directors (the “Board”) of CSPC Pharmaceutical Group Limited (the “Company”, together with its subsidiaries, the “Group”) is pleased to announce that, as proposed by the National Health Commission of the People’s Republic of China and consented by the National Medical Products Administration (the “NMPA”) after assessment, the bivalent COVID-19 mRNA vaccine (XBB.1.5+BQ.1) (SYS6006.32) developed by the Group (the “Product”) has been included for emergency use in China for the prevention of COVID-19 caused by the infection of SARS-CoV-2. SYS6006.32, targeting the dominant variants represented by XBB.1.5, is a bivalent mRNA vaccine against XBB.1.5 and BQ.1 variants developed by the Group on the foundation of the first generation COVID-19 mRNA vaccine (brand name: Duentai (度恩泰)), which has also been included for emergency use in China. In the clinical trials, the Product not only induced very high immunogenicity against the dominant variants EG.5 and XBB.1.5, with live virus neutralizing antibody level 48 and 34 times the level before vaccination, and 4.9 and 5.0 times the level induced byDuentai respectively, but also induced broad-spectrum cross-variant immunity against variants including XBB.1.16, BA.5, XBB.2.3, and BA.2.86. This indicates that the Product may provide good protection against the current dominant strains aswell aspotential prevalent strains inthe future. The Product also had agood safety profile. The types and severity of the most adverse reactions were comparable to Duentai, with no additional risks. Thelevel oftheneutralizing antibodies intheelderly group wascomparable totheadult group, but with a better safety profile. This indicates that the Product may provide better protection for the elderly. - 1 - The Product adopts advanced technology with independent intellectual property rights, with the advantages ofachieving higher production capacity, better process reproducibility, scale-up andlarge- scale production more easily. The Product demonstrates good consistency in product quality, all batches of samples submitted to the National Institutes for Food and Drug Control have passed the required tests. The Product is stable and can be stored at 2-8°C for a long time. Key raw materials andexcipients used intheproduction, such ascore lipids andcapanalogs formRNA preparation, are all manufactured by the Group, while other excipients and key equipment are all domestically sourced, thus no reliance on overseas suppliers in the supply chain. The Product isanother mRNA vaccine product that has been authorized for emergency use following Duentai, which demonstrates the research and development strength of the Group’s nucleic acid platform. The Group will actively promote the development of other products on the platform. By order of the Board CSPC Pharmaceutical Group Limited CAI Dongchen Chairman Hong Kong, 1 December 2023 As at the date of this announcement, the Board comprises Mr. CAI Dongchen, Mr. ZHANG Cuilong, Mr. WANG Zhenguo, Mr. PAN Weidong, Mr. WANG Huaiyu, Dr. LI Chunlei, Dr. WANG Qingxi, Mr. CHAK Kin Man and Dr. JIANG Hao as executive directors; and Mr. WANG Bo, Mr. CHEN Chuan, Prof. WANG Hongguang, Mr. AU Chun Kwok Alan, Mr. LAW Cheuk Kin Stephen and Ms. LI Quan as independent non-executive directors. - 2 -

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