Abstract
The search for effective vaccines to stop the COVID-19 pandemic has led to an unprecedented amount of global scientific production and activity. This study aimed to analyze global scientific production on the different vaccine types (mRNA and conventional) that were validated for COVID-19 during the years 2020-2021. The scientific production generated on COVID-19 vaccines during the period 2020-2021 totaled the enormous amount of 20,459 studies published. New mRNA vaccines clearly showed higher production levels than conventional vaccines (viral and inactivated vectors), with 786 and 350 studies, respectively. The USA is the undisputed leader in the global production on COVID-19 vaccines, with Israel and Italy also playing an important role. Among the journals publishing works in this field, the New England Journal of Medicine, the British Medical Journal, and Vaccines stand out from the rest as the most important. The keyword 'immunogenicity' and its derivatives have been more researched for the new mRNA vaccines, while thrombosis has been more studied for conventional vaccines. The massive scientific production generated on COVID-19 vaccines in only two years has shown the enormous gravity of the pandemic and the extreme urgency to find a solution. This high scientific production and the main keywords found for the mRNA vaccines indicate the great potential that these vaccines have against COVID-19 and future infectious diseases. Moreover, this study provides valuable information for guiding future research lines and promoting international collaboration for an effective solution.