Protein Sciences Corporation is a biotech company based in Meriden, Connecticut. The company develops and produces vaccines and biopharmaceuticals for use against influenza and other diseases. In 2017, the company was acquired by Sanofi for $750 million.
Protein Sciences has developed a novel method for vaccine production, using a genetically modified baculovirus that is allowed to reproduce in insect cells. This method reduces the lead time for vaccine production to six to eight weeks, considerably shorter than the conventional, egg-based, method. The company has applied for a Biologic License Application with the U.S. Food and Drug Administration (FDA) for Flublok, their seasonal influenza vaccine.  On Jan 17, 2013, Protein Sciences announced that the U.S. Food and Drug Administration had approved Flublok influenza vaccine for use in people 18-49 years old. Since then, Flublok's age indication has been expanded to all adults 18 and older as of October 29, 2014. Flublok is currently available. 
- "Sanofi to acquire Protein Sciences". sanofi.com. Retrieved 27 November 2017.
- Journal of the American Medical Association, Vol. 297:Safety and Immunogenicity of a Baculovirus-Expressed Hemagglutinin Influenza Vaccine
- The NIH Biomedical Research Response to Influenza Archived 2016-11-04 at the Wayback Machine.
- NBC Connecticut: Swine Flu Vaccine Could Be Ready in 6 Weeks
- "FDA Panel to Consider New Flu Vaccine Technology". Wall Street Journal. November 13, 2009. Retrieved 2009-11-20.
Protein Sciences Corp. a private firm based in Meriden, Conn., is seeking Food and Drug Administration approval for its FluBlok seasonal influenza vaccine, although the same technology can be used to make an H1N1 vaccine to protect against the swine flu. The vaccine will be reviewed by outside medical experts who serve on the agency's vaccine advisory panel.
- Flublok, (Influenza Vaccine, Recombinant Hemagglutinin), Briefing Document, FDA Vaccines and Related Biological Products Advisory Committee Meeting, November 19, 2009
- Andrew Pollack, "Rapidly Produced Flu Vaccine Wins F.D.A. Approval", The New York Times, January 16, 2013
- FDA press release