Why should Anhui Zhifei COVID-19 strengthen the needle with three needles? Which one is better, Anhui Zhifei or Beijing Kexing Zhongwei

At present, five brands of COVID-19 vaccine have been approved for marketing in China, and one of them is COVID-19 vaccine, Anhui Zhifei. Compared with the inactivated vaccine widely inoculated before, this recombinant vaccine needs three shots. So, why did Anhui Zhifei COVID-19 Vaccine get three shots? Which is better than Beijing Kexing Zhongwei?

I. Why are three injections of Anhui Zhifei COVID-19 vaccine?

Vaccines produced by different companies have different technical routes and mechanisms of action, so the number of injections required also varies. There are currently three types of vaccines available for sale in China, including adenovirus vector vaccines that require one dose, inactivated vaccines that require two doses, and recombinant protein vaccines that require three doses. After two doses of recombinant protein vaccine, 76% can produce neutralizing antibodies; After receiving three doses, 97% can produce neutralizing antibodies, which means that receiving three doses is the most effective.

Anhui Zhifei COVID-19 vaccine is a recombinant subunit vaccine. The principle is to recombine the S protein receptor binding region (RBD) gene of COVID-19 into the Chinese hamster ovary (CHO) cell gene, express it in vitro to form RBD dimer, and add aluminum hydroxide adjuvant to improve immunogenicity.

II. Which is better, Anhui Zhifei COVID-19 Vaccine or Beijing Kexing Zhongwei?

1. Inactivated vaccine

of Beijing Sinovac: Vero cell inactivated vaccine (also known as Kerr Raffles)

Vaccine approved on: February 5, 2021

Vaccine safety: COVID-19 inactivated vaccine of Sinovac was called Kerr Raffles, and the vaccine entered Phase I and Phase II clinical studies in April 2020, and the safety and effectiveness of the vaccine were confirmed through studies. The Phase III clinical study carried out in Brazil and Türkiye evaluated the protective efficacy of Kelafu in high-risk groups (medical staff receiving patients with COVID-19 pneumonia) and the general population respectively. Both countries adopted a multicenter, randomized, double-blind, placebo parallel control design, and the main endpoint was the incidence rate of COVID-19 induced diseases 14 days after the vaccination of two doses of vaccine or placebo.

Vaccine effectiveness: On February 5, Beijing Kexing Zhongwei Biotechnology Co., Ltd. announced the phase III clinical research data of the novel coronavirus inactivated vaccine Kelafu. The results showed that through the Phase III clinical studies in Brazil and Türkiye, the protective effect of the vaccine against the disease caused by COVID-19 was more than 50%, up to 91.25%.

Inoculation dose: 2 doses

2. Zhifei Biological Recombinant COVID-19 Vaccine (CHO Cell)

Vaccine approval time: March 10, 2021

Vaccine type: Recombinant COVID-19 Vaccine (CHO Cell)

Vaccine safety: According to the results of Phase I and Phase II clinical trials of the recombinant protein subunit vaccine (ZF2001) developed by Anhui Zhifei reported in the world famous medical journal Lancet Infectious Diseases, the vaccine has good safety, and most of the enrollees have not observed adverse reactions or mild or moderate adverse reactions, such as redness, swelling, pain and itching at the injection site, etc. It is a common reaction after vaccination of recombinant protein vaccine. No serious adverse events related to vaccines have occurred.

Vaccine effectiveness: According to data, after receiving two doses of Zhifei vaccine, 76% of people can produce neutralizing antibodies. 97% of people can produce neutralizing antibodies after receiving three doses of the vaccine. The geometric mean titer (GMT) of the antibody reached 102.5, which exceeded the serum neutralizing antibody level of 89 COVID-19 rehabilitation patients.

Inoculation dose: 3 doses

In short, the COVID-19 vaccine of Anhui Zhifei and the COVID-19 vaccine of Beijing Biotech are both approved by the State Food and Drug Administration for production and marketing, and their safety and effectiveness are supported by data, so everyone can be assured of vaccination.