Flu vaccines 48% effective so far this season, CDC says

This year’s flu vaccine is working for almost half of recipients, the CDC says in an update on what it’s calling a "moderate" season. But, as of data ending Feb. 4, government experts don’t expect the season to come to a close right away.

CDC anticipates "several more weeks" of flu activity in parts of the U.S., according to an agency update. So far, vaccines have been 48% effective in preventing flu-related medical visits, the CDC estimates.

That compares to 59% for last year and 19% for the year before, according to the CDC. Over 10 previous flu seasons, vaccine effectiveness has fluctuated each year, often ending up with a percentage in the 40s or 50s.

Separately this year, CDC experts recommended against any use of AstraZeneca’s FluMist on efficacy concerns from three previous seasons. AZ said it’s working to assess the situation.

All year round, experts monitor the virus and select strains for the upcoming season. But, in an effort to improve on so-so efficacy and avoid strain drift, several biopharma companies are working on "universal" vaccines that fight a range of strains over multiple years.

Sanofi, the world’s largest flu vaccine manufacturer, in late 2015 unveiled its work in the area. It announced a vax project dubbed Cobra that’s designed to protect against multiple strains by using common sequences the strains share.

Other companies and groups that have gotten into universal flu vaccine work include Johnson & Johnson’s Crucell and Scripps Research Institute, plus biotechs BiondVax and FluGen.