After the outbreak of the pandemic, pharmaceutical companies quickly began developing coronavirus vaccines. According to the World Health Organization (WHO), 48 vaccines have been tested in different countries, with 11 passing through to phase III of trials. Meanwhile, another 164 alternative vaccines are passing preclinical testing. ## What vaccines are available? Pfizer/BioNTech (USA–Germany), Moderna (USA), NITsEM named after N.F. Gamaleya (Russia) and AstraZeneca (UK–Sweden) were the first to announce the results of clinical trials and the efficacy of their vaccines. So far, only Pfizer/BioNTech, Moderna, and the Center named after N.F. Gamaleya has announced the results of the last phase of the trials. The prospects are very positive, but it is still too early to talk about the final results. Meanwhile, the Novosibirsk Center of Virology Vector (Russia), the Center named after Chumakov (Russia), CanSino Biological (China), AstraZeneca (UK—Sweden), Johnson & Johnson (USA), Novavax (USA), and Sinovac (China) are operating final stage trials. A vaccine should be more than 50 percent effective to be registered. ## Market leaders __The BNT162b2 vaccine__ is a project of the American Pfizer and German BioNTech. According to clinical trials, this vaccine is 95 percent effective. The vaccination is performed in two stages, with an interval of 21 days. The immunity occurs in 7 days after the second dose. It is the first vaccine in the world that has passed through all three phases of clinical trials. Pfizer and BioNtech have signed agreements for supplying their vaccines with the United States, United Kingdom, European Union, and Japan. *How It Works.* This vaccine contains RNA (ribonucleic acid), which includes the genetic code of the S protein of the virus. After vaccination, the body starts to develop antibodies to this virus protein. *Contraindications.* Allergic reactions to any component of the vaccine. *Storage conditions.* 10 days under the temperature of -94 °F, which makes transportation complex and costly. __The Moderna vaccine__ is 94,5 percent effective. The vaccination is performed in two stages with a 28-day interval. *How It Works.* It is also an RNA vaccine. Unlike the BNT162b2 vaccine, this vaccine creates immunity not to the S protein of the virus but to the virus’s RNA. Amazingly, scientists developed this vaccine just 66 days after deciphering the genetic code of the virus. *Contraindications*. Allergic reactions to any component of the vaccine. *Storage conditions.* 6 months with a temperature of -4 °F. __RNA vaccines have never before been used in healthcare, and this is the first time they have been tested on humans. This cutting-edge technology is still in the research stage. It is too early to speak about the absolute safety of the vaccine, especially for children under 12 years of age and pregnant women.__ __The AZD1222 vaccine__ was developed by Oxford University and the English–Swedish company AstraZeneca. This vaccine is 70.4 percent effective. *How it works.* This vaccine is based on human adenovirus (a widespread virus that causes colds with humans), which works as a vector shuttling the genetic material of the virus targeted by the vaccine into our body cells. It is often referred to as an Oxford vaccine; for the moment, it has passed through to phase III of the trials. *Contraindications.* No contraindications are listed. However, based on the type of the vaccine, it can be assumed that possible contraindications may include hypersensitivity to any component of the vaccine, history of severe allergic reactions, pregnancy, and lactation, or age under 18 years old. *Storage conditions.* This vaccine can be stored for 6 months between 35,6 up to 46,4 °F. __Sputnik V__ is the first registered Russian vaccine. The announced effectiveness of the vaccine is 92 percent. The vaccination is performed in 2 stages with an interval of 3 weeks. *How it works.* Sputnik V is a vector vaccine (following the same principle as AstraZeneca’s vaccine). *Contraindications.* Allergic reactions, pregnancy, and lactation, age under 18 years old. *Storage conditions.* 6 months at a temperature under -0,4 °F. The vaccine can be stored at the room’s temperature for no more than 30 minutes. ## What to expect after getting a vaccine All vaccines have similar side effects, which include increased fatigue, headache and muscle pain, chills, fever, and pain at the place of injection. It should be noted that two-phase vaccines start working only after the second injection, so it is necessary to take all precautions between the first and second visit to the hospital. The highest IgG-57 antibody response and post-vaccine immunity happen 42–55 days after the first dose. Currently, there is no unambiguous data about how long these antibodies stay in the body.