GIARDINI NAXOS, SICILY, ITALY -- April 10, 2003 -- ProQuad, the first vaccine candidate to protect children against measles, mumps, rubella and varicella appears safe and well-tolerated and created immunogenic markers similar to those seen with other vaccines.
 

"This is first in the world vaccine aimed at four of the major childhood diseases," said Jay Lieberman, MD, a researcher at the University of California Los Angeles Center for Vaccine Research, Torrance, California. "We think that if we can reduce the number of shots young children have to take to be protected against these diseases we have the potential to get our numbers up -- to around 90% vaccinated against chicken pox."
 

Dr. Lieberman presented the findings here April 10th in a poster presentation at the 21st Annual Meeting of the European Society for Paediatric Infectious Diseases.
 

Dr. Lieberman, who is also associate professor of medicine at the University of California at Irvine, said his study compared the immunogenicity of three different lots of the vaccine -- a step required by the US Food and Drug Administration to show that the vaccine can be manufactured consistently.
 

The one-shot vaccine was given to about three-fourths of the 3,928 healthy children between 12 and 23 months of age. The other children were administered one injection of the MMR-II vaccine, which has been given to children for decades to protect against measles, mumps and rubella, and a second injection of Varivax -- a chicken pox vaccine. The shots were administered to different sites.
 

Seroconversion of the children receiving different lots of vaccine were similar and, in turn, were similar to seroconversion seen in children receiving the two approved vaccines.
 

Dr. Lieberman reported the following data:
 

--In measles, 97.6% of children receiving the ProQuad vaccine showed seroconversion compared to 98.5% of those getting the two vaccines.
 

--In mumps, 96% of children receiving ProQuad versus 97.9% of those getting the two vaccines showed seroconversion.
 

--In rubella, 98.8% of the children getting ProQuad and 99.2% of those getting two vaccines showed seroconversion.
 

--In varicella 93.5% of children getting ProQuad and 95% of those getting the double shot showed seroconversion.
 

Dr. Lieberman said that children receiving ProQuad appeared to suffer more fevers in the 6 weeks following the inoculations but he said the figures were clinically irrelevant (39.1% versus 33.1%, P=0.001).

"There was no difference between the children getting ProQuad and those getting the two vaccines in the more important febrile seizure related incidents [0.3% for both groups]," he pointed out.
 

The study was supported by Merck Research Laboratories, developer of the vaccine. He said he expects that the company is likely to file for approval of the vaccine "soon" but he said he was not aware of an exact timetable to do so.
 

"Doctors are excited about the idea that they can deliver this vaccine in one shot," Dr. Lieberman said. "That has the potential to enhance compliance, especially against chicken pox at an early age."