Why isn’t the flu vaccine better?
Nearly all flu vaccines are made of viruses grown in hens’ eggs, a process dating from the 1940s that takes between six and eight months. One egg is inoculated with a flu virus that grows well in eggs and has been equipped with the H and N proteins from a virus strain thought likely to circulate next winter. The world has the capacity to make 1.5 billion doses of vaccine each protecting against three or four strains, and so each requiring three to four eggs. Vaccines this year contain both the circulating A strains, and one or both of the Bs. Actual production varies with predicted demand.
This process means virologists must predict months in advance which viruses will
Published at Wed, 03 Jan 2018 12:00:00 +0000