{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T13:12:20Z","timestamp":1791983540066,"version":"4.4.0"},"reference-count":26,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2021,1,23]],"date-time":"2021-01-23T00:00:00Z","timestamp":1611360000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Center for Biologics Evaluation and Research (CBER)-U.S. Food and Drug Administration","award":["U01 FD005959"],"award-info":[{"award-number":["U01 FD005959"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Vaccines"],"abstract":"<jats:p>The global research and development of mRNA vaccines have been prodigious over the past decade, and the work in this field has been stimulated by the urgent need for rapid development of vaccines in response to an emergent disease such as the current COVID-19 pandemic. Nevertheless, there remain gaps in our understanding of the mechanism of action of mRNA vaccines, as well as their long-term performance in areas such as safety and efficacy. This paper reviews the technologies and processes used for developing mRNA prophylactic vaccines, the current status of vaccine development, and discusses the immune responses induced by mRNA vaccines. It also discusses important issues with regard to the evaluation of mRNA vaccines from regulatory perspectives. Setting global norms and standards for biologicals including vaccines to assure their quality, safety and efficacy has been a WHO mandate and a core function for more than 70 years. New initiatives are ongoing at WHO to arrive at a broad consensus to formulate international guidance on the manufacture and quality control, as well as nonclinical and clinical evaluation of mRNA vaccines, which is deemed necessary to facilitate international convergence of manufacturing and regulatory practices and provide support to National Regulatory Authorities in WHO member states.<\/jats:p>","DOI":"10.3390\/vaccines9020081","type":"journal-article","created":{"date-parts":[[2021,1,25]],"date-time":"2021-01-25T12:28:31Z","timestamp":1611577711000},"page":"81","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":100,"title":["Development of mRNA Vaccines: Scientific and Regulatory Issues"],"prefix":"10.3390","volume":"9","author":[{"given":"Ivana","family":"Knezevic","sequence":"first","affiliation":[{"name":"Department of Health Product Policy and Standards, World Health Organization, Avenue Appia 20, CH-1211 Geneva, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Margaret A.","family":"Liu","sequence":"additional","affiliation":[{"name":"ProTherImmune 3656 Happy Valley Road, Lafayette, CA 94549, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Keith","family":"Peden","sequence":"additional","affiliation":[{"name":"Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, US Food &amp; Drug Administration, Silver Spring, MD 20993, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tiequn","family":"Zhou","sequence":"additional","affiliation":[{"name":"Department of Health Product Policy and Standards, World Health Organization, Avenue Appia 20, CH-1211 Geneva, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hye-Na","family":"Kang","sequence":"additional","affiliation":[{"name":"Department of Health Product Policy and Standards, World Health Organization, Avenue Appia 20, CH-1211 Geneva, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,1,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Liu, M.A. (2019). 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