Effects of dose and strain of vaccine on success of measles vaccination of infants aged 4-5 months.
Whittle HC., Mann G., Eccles M., O'Neill K., Jupp L., Hanlon P., Hanlon L., Marsh V.
Small-scale trials of the Edmonston-Zagreb (E-Z) measles vaccine were undertaken to determine the dose necessary to immunise 4-6-month-old infants. Antibody responses, measured 16 weeks after vaccination, were dose dependent: 40,000 plaque forming units given subcutaneously resulted in positive responses in all infants and higher antibody levels than doses of 20,000 or 10,000 units (10,000 units gave a failure rate of 25%). In further trials the E-Z vaccine was compared with the Schwarz vaccine, both being given in subcutaneous doses of 40,000 plaque forming units. In infants aged 20 weeks the E-Z vaccine produced higher levels of measles antibody and in those aged 18 weeks its superiority showed in a lower proportion failing to respond (3 of 39 versus 19 of 35).