On November 20, FDA approved a new flu vaccine , grown in mammalian cells. It appears to work in adults below age 50, but the manufacturer was only able to show it was no worse than a different flu vaccine at generating antibodies in those over 50. That is a poor correlate for effectiveness. According to FDA:
"The use of Flucelvax in people older than 49 is supported by antibody responses in about 1,700 adults which showed it to be comparable to Agriflu, an egg-based seasonal influenza vaccine approved by FDA for use in people 18 years and older..."
UPDATE:AHRP on Cochrane findings re flu vaccine efficacy.
1. "During some influenza seasons vaccination offers substantially more protection for most of the population than being unvaccinated; however, influenza vaccine protection is markedly lower than for most routinely recommended vaccines and is suboptimal. We reviewed all studies that evaluated influenza vaccine efficacy and effectiveness published from 1967 to 2012 and summarized those that used rigorous methodology and had specific infection outcome end points. For TIV, results demonstrated: (1) evidence of moderate protection (pooled estimate of 59%) for healthy adults 18 to 64 years of age, (2) inconsistent evidence of protection in children age 2 to 17 years, and (3) a paucity of evidence for protection in adults 65 years of age and older. For LAIV, (the live vaccine used mostly in children) results demonstrated(1) evidence of high protection (pooled estimate of 83%) for young children 6 months to 7 years of age, (2) inconsistent evidence of protection in adults 60 years of age and older, and (3) a lack of evidence for protection in individuals between 8 and 59 years of age.
2. Current policy goals for influenza vaccines focus on increasing production capacity and have not addressed key public health challenges related to the effectiveness of current vaccines. Current influenza vaccine public health policy focuses on: (1) expanding current seasonal influenza vaccination campaigns to vaccinate an increasing proportion of the population each year using current HA-head vaccines, (2) ensuring that capacity is available to rapidly produce HA-head vaccines at the onset of an influenza pandemic, and (3) improving vaccine access, particularly in developing countries. While these are all laudable goals, they provide only for incremental improvements. Public health policy has not yet recognized the critical limitations of the current HA-head vaccines or the limited impact of our current strategies. While officials are now recognizing that better vaccines are needed, the current policy focus and the lack of acknowledgment of the current vaccines’ shortcomings have created an environment lacking the political will to develop novel-antigen game-changing vaccines. Public health policy leaders must overcome these barriers and make development of game-changing vaccines a national priority.