Last December, the United Kingdom (UK) became the first nation to authorize and to begin vaccinating its citizens. On Dec. 2, 2020, the UK Medicines & Healthcare products Regulatory Agency approved the COVID-19 vaccine jointly developed by Pfizer and BioNTech. More than 600,000 UK citizens have received the vaccine. The first COVID-19 vaccines are being introduced in not only the UK but also in other countries. Middle Eastern and Latin American countries, such as Mexico, have secured vaccines and have started mass vaccinations. China and Russia, which have self-developed vaccines, have also begun vaccinations.
Vaccines typically require years of research and testing before reaching the public. However, due to the COVID-19 pandemic, scientists embarked on a race to produce COVID-19 vaccines in record time. According to The New York Times, “researchers are currently testing 64 vaccines in clinical trials on humans, and 19 have reached the final stages of testing. At least 85 preclinical vaccines are under active investigation in animals.” 
Currently, there are three main types of COVID-19 vaccines: viral-vector, protein subunit, and messenger RNA (mRNA) vaccines. Viral vector vaccines use a virus that has been genetically engineered. This type includes the COVID-19 vaccine co-developed by Oxford University and AstraZeneca. Protein subunit vaccines use harmless fragments of proteins or protein shells that mimic the virus. Lastly, mRNA vaccines use genetically engineered RNA to generate proteins that safely prompt an immune response. This type includes the COVID-19 vaccines developed by Pfizer/BioNTech and Moderna. Although conventional vaccine development methods consume much time, mRNA vaccines reduced development time since the vaccines eliminate much of the manufacturing process. Furthermore, mRNA molecules are far simpler than proteins. For vaccines, mRNA is manufactured through chemical rather than biological synthesis, so they can be redesigned, scaled up, and mass-produced much quickly compared to conventional vaccines.
Along with the race for vaccine development, a race for vaccine procurement is also fierce. Bloomberg, an economic magazine, investigated supply contracts for the COVID-19 vaccines from around the world and revealed the percentage of vaccines secured compared to the population of each country. For example, 100% means that the country has secured the exact number of vaccines needed to vaccinate every citizen. Canada leads the pack with 303.5%, followed by the UK (294.7%), New Zealand (246.8%), and Australia (229.9%). While many countries have secured the number of vaccines that exceed their population, Korea has secured 70.8%. Considering the number of vaccines secured only, India ranked first, securing 2,200 million doses of vaccines, and was followed by the European Union and the U.S. 
According to statistics, the Oxford/AstraZeneca vaccine supplied the largest amount of 2,925 million doses. Pfizer/BioNTech and Moderna vaccines’ procurement volume was relatively small, with 716 million and 411 million doses, respectively. Although they were developed the earliest, the two vaccines had to adjust production and supply due to a raw material problem.
With the introduction of the vaccines, standards for people subject to preferential vaccination are announced one after another. The United States’ Centers for Disease Control and Prevention has issued a recommendation that medical workers and nursing home patients be vaccinated first in the U.S. Other countries’ vaccination standards are similar to those of the U.S. The reason behind this is that senior and base patients have a high fatality rate in case of infection, and medical staff must have immunity to safely treat patients. 
In the case of Korea, specific standards are yet to be provided. Nevertheless, Park Neung-hoo, former Minister of Health and Welfare, claimed that prioritizing COVID-19 vulnerable groups for vaccinations is being considered. Such groups include senior citizens, those who live at group facilities, chronic disease patients, and social services personnel such as healthcare workers.
The impact of COVID-19 vaccines on the pandemic will depend on several factors, including the effectiveness of the vaccines: how quickly they are approved, manufactured, and delivered. Furthermore, the impact will also depend on how many people get vaccinated.
 *Statistics provided in this article were last updated on Dec. 30, 2020 (GMT+9).