Is it safe to take several shots of recombinant COVID-19 vaccine and COVID-19 vaccine

Several injections of recombinant COVID-19 vaccine

According to the national Technical Guidelines for COVID-19 Vaccination (First Edition), three doses of recombinant COVID-19 vaccine were administered; The recommended interval for vaccination between adjacent doses is ≥ 4 weeks. The second dose should be completed within 8 weeks after the first dose, and the third dose should be completed within 6 months after the first dose. The recombinant COVID-19 vaccine was expressed in CHO cells. The outstanding representative of recombinant protein vaccine is hepatitis B vaccine, which has 30 years of experience in production and use. The rising stars are HPV vaccine (commonly known as cervical cancer vaccine) in 2006, recombinant protein influenza vaccine in 2013, hepatitis E vaccine in 2016, and recombinant protein herpes zoster vaccine in 2017. These vaccines have demonstrated good safety and efficacy in their application.

Why three injections of recombinant COVID-19 vaccine

Three injections of recombinant COVID-19 vaccine are needed. After two injections of the vaccine, 76% can produce neutralizing antibodies; After three doses of vaccination, 97% can produce neutralizing antibodies, with high antibody levels that can effectively reach twice the serum antibody level of recovered patients and induce B/T cell immunity. Therefore, getting three doses of the vaccine can be said to ensure its effectiveness. Although vaccination can generate immunity and greatly reduce the risk of infection, the protective effect of any vaccine cannot reach 100%. Some people may not produce enough antibodies after vaccination and still face the risk of infection, especially in situations where social barriers to prevention have not yet been established. Therefore, even after vaccination, it is important to maintain good hygiene habits such as wearing masks, washing hands frequently, and maintaining social distancing. Generally speaking, patients with novel coronavirus will be infected with infectious diseases or asymptomatic infections. They should have the same protective effect as vaccination. Clinical trials have not yet provided data on the safety and efficacy of the new treatment population for COVID-19. Therefore, novel coronavirus vaccine is not recommended for people cured of novel coronavirus.

Is the recombinant COVID-19 vaccine safe. The Phase I, Phase II and Phase III clinical trials of COVID-19 vaccine in China, as well as the emergency vaccination of nearly one million people who have been carried out under the premise of voluntary informed consent according to laws and regulations, fully demonstrate that COVID-19 vaccine in China is very safe, with some minor adverse reactions, but no serious adverse reactions. Meanwhile, during our emergency use, over 60000 vaccine recipients have traveled to high-risk areas overseas, and we have not received any reports of severe infections so far, which proves from another perspective that our vaccine has a certain protective effect.

What to pay attention to when vaccinating recombinant COVID-19 vaccine

The vaccination procedure of this vaccine is similar to that of the well-known hepatitis B vaccine, which requires three shots. On the one hand, we now have higher requirements for the immune level of COVID-19 vaccine. Although two injections can produce neutralizing antibody levels that are only slightly lower than those of the convalescent patients' serum, after three injections, not only the neutralizing antibody level has doubled again, which can reach twice the level of COVID-19 convalescent patients, but also the immune effect is more lasting. On the other hand, for recombinant protein vaccines with similar technological paths, the three shot vaccination procedure is a historical experience, and for safety reasons, the three shot vaccination procedure is still adopted. The second dose should be administered within 4 to 8 weeks after the first dose, and the third dose should be administered at least 4 weeks after the second dose and within 6 months of the first dose.