Guide to the No-Thimerosal Influenza Vaccine Choices in the USA for the 2013-2014 Flu Season

Introduction

Up until the 2002-2003 influenza (flu) season, the only flu vaccines marketed in the USA were Thimerosal-preserved trivalent inactivated-influenza vaccines, where the influenza viruses were grown in embryonated eggs . After a suitable growth period (typically about 48 hours at 37 °C), the viruses are harvested by removing the allantoic fluid – about 10 ml per egg, inactivated with formaldehyde (or another aldehyde) and processed to make the final inactivated viral concentrates which are blended with other ingredients to form the final vaccine formulation. In general, these influenza vaccines contained two (2) inactivated A-strain influenza viruses and one (1) inactivated B-strain influenza virus preserved with a 0.01% level of Thimerosal.

Moreover, until 1997, there was no population recommendation that pregnant women be given a flu shot at any stage in pregnancy and, until 2002, there was no general recommendation to vaccinate any agegroup of children with a flu vaccine each year and the general flu-vaccination programs were aimed at those 65 years of age and older.