Injected flu vaccines don’t shed, per se. However nasally-received flu vaccines like FluMist shed live virus for up to 2 weeks; read the package insert. In a clinical trial, an unvaccinated elementary school child developed the same vaccine-strain influenza as her peers who received the intranasal vaccine. You may wish to avoid people who’ve had FluMist for 2 weeks.
Also check the package insert for information on injectable influenza vaccines. Contrary to the CDC’s recommendation, vaccine manufacturers HAVE NOT TESTED the influenza vaccine on pregnant women. The CDC simply states that the vaccine has been given to millions of women, but whether that government agency and manufacturers are doing adequate postmarketing tracking of adverse events in pregnant women is subject to debate.
Most injected influenza vaccines contain 25 micrograms of ethylmercury from Thimerosal, a bacteriostatic preservative whose job is to kill cells. Search PubMed for studies, especially a recent UC-Davis study showing that Thimerosal kills dendrites and damages calcium channels (therefore immunity) at 20–40 parts per billion. 25 micrograms = 50,000 ppb in each flu shot, which is only considered “safe” for persons weighing 550 lbs.
Mercury in any form is a neurotoxin, and at extremely low levels. Consider reading the new book “The Age of Autism: Mercury, Medicine, and a Man-made Epidemic,“a book by Dan Olmsted & Mark Blaxill. Mercury binds to protein and fat tissue such as the brain and kidneys. A 2005 Washington macaque study found that ethylmercury from Thimerosal left the bloodstream more quickly than methylmercury from fish—because the ethylmercury bound with brain tissue twice as fast.
Also consider reading “What Your Doctor May Not Tell You About Children’s Vaccinations” by Stephanie Cave, MD, and “The Vaccine Book: Making the Right Decision for Your Child” by Dr. Robert Sears. These are not “anti-vaccine” in content; they advocate for vaccine use tailored to the individual’s unique medical condition.