The study was performed in the State of S.Paulo, SP, Brazil, with the purpose of finding out whether reusable (glass) and disposable hypodermic syringes used for administration of live attenuated measles vaccines would interfere with their virus. At least six different experiments using two distinct lots of vaccines were carried out. Each time, a lot was reconstituted with reusable and disposable syringes in parallel to form separate pools from which samples were collected hourly from zero to the sixtieth hour after reconstitution for virus titration in monolayers of Vero cells. The straight line regression system chosen for the analysis of the results demonstrated that although vaccines reconstituted with both types of syringes presented a statistically significative titer decrease as time went by, there was a more pronounced decrease for vaccines manipulated with the glass syringes. The fact that the disposable syringes affected the titer of the virus present in the live, attenuated measles vaccine less confirmed that the preconization and routine usage of this type of syringe by the Health Department of the State of S.Paulo, Brazil, is ideal and highly recommended because it preserves the vaccine from reconstitution to administration better, and thus, its efficacy in preventing the infection.
Measles vaccine; Efficacy; Syringes; Comparative studies