Influenza Vaccine: Split-Product versus Whole-Virus Types — How Do They Differ?

Although the swine-influenza-immunization campaign has been suspended for all but high-risk groups, it was attended by other problems besides the well publicized but very rare apparent association with Guillain-Barre syndrome. One of these other problems relates to the difference between split-product and whole-virus types of vaccines, a difference not generally appreciated by physicians. The problem is worth discussing because the basic principles apply to the manufacture of influenza vaccines other than the current swine-virus vaccine. Different manufacturing processes have been developed in the hope of minimizing reactivity (systemic type, fever, malaise, headache and myalgia; local type, arm pain, redness and . . .