The Future of COVID-19 Vaccines and Thailand

Abstract

The COVID-19 outbreak began in late 2019 in Wuhan, China. As of February 2021, the SARS-COV-2 virus has spread to 186 countries worldwide, infecting 103 million people and killing 2.2 million people. Social distancing measures and reducing the movement of people within the country have caused the population to lose immunity to the SARS-COV-2 virus, and they will easily become sick when infected. The elderly and people with chronic diseases are at high risk of death if infected. Vaccination must be widespread to create herd immunity of at least 60% of the population to end the epidemic. Most of the world's population is waiting for a safe and effective COVID-19 vaccine. An effective COVID-19 vaccine should be able to stimulate the production of both antibodies to inhibit the SARS-CoV-2 virus and T cells in sufficient quantities to protect against the disease. Although vaccines administered in the respiratory tract can stimulate immunity directly in the respiratory tract, they are effective in eliminating SARS-CoV-2 during the early stages of infection, which is very suitable for use in high-risk groups. However, the method of administering respiratory vaccines is still inferior to injectable vaccines in terms of safety and efficacy, and the vaccination device is not yet suitable for use in poor countries. Therefore, the injection vaccine is still the most suitable. The development of COVID-19 vaccines is being rushed. In less than 1 year, more than 13 types have entered phase 3 of human studies, and 4 types have preliminary results. There are about 10 types of vaccines being studied, but currently, 4 have passed phase 3 and are approved for emergency use: 1. Inactivated vaccine: There are vaccines from China Sinovac, Sinopharm, and there will be another Indian vaccine soon. 2. Using a virus as a carrier (Virus Vector) to enter cells to create antigens and stimulate immunity, including the Oxford-AstraZeneca vaccine from England, Sputnik V from Russia, and Cansino from China. 3. mRNA vaccines use mRNA wrapped in fat to import into cells, including the Moderna and Pfizer vaccines. 4. Subunit vaccines use cellular organisms to create proteins. Proteins are combined with immune stimulants, such as the American Novavax vaccine and another Chinese company in Anghui. Currently, all vaccines have been studied to prevent the severity of the disease. Previous studies are preliminary results. The target group of people who received real and fake vaccines is 90-100 infected or symptomatic patients. However, the goal is to end the study with 160 patients. The preliminary report is a short-term efficacy study. No more than 3 months after vaccination, these studies do not indicate long-term efficacy, such as 6 months to 1 year. The longer the disease prevention lasts, the less effective it may be, or the same or more. Currently, it still needs to be monitored. Similarly, vaccine side effects also need to be monitored in the long term. It takes a year or several years for the population to have immunity from infection or receive a vaccine. It will take a year or several years to end the outbreak. Preventive measures and living in the new way of life must continue with discipline, patience, and consideration for the community or society, as well as sharing. Therefore, it is still necessary to continue wearing masks, washing hands, and setting a distance between individuals and society.