First Clinical Study of a New Vaccine Against Pediatric Croup Demonstrates Safety and Tolerability in Adult Volunteers at St. Jude Children's Research Hospital

MEMPHIS, Tenn. -- Scientists at St. Jude Children's Research Hospital are investigating in adults the use of a vaccine given by nose drops that might ultimately protect children against human parainfluenza virus-type 1 (hPIV-1). This virus is the most common cause of croup, a pediatric respiratory disease that causes almost 30,000 hospitalizations each

year and many more emergency room visits. These findings were published in the current issue of Vaccine.

Successful development of an effective hPIV-1 vaccine would be significant

because none is currently available and a vaccine that is given to infants

using nose drops would eliminate the discomfort and complications of

injections.

Because the vaccine contains a live virus, it should stimulate both

antibody and cellular immune responses, which together may provide durable

protection from hPIV-1. In cellular immunity, special cells, rather than

antibodies, destroy virus-infected cells inside the body.

The vaccine consists of Sendai virus (SeV), a mouse virus that is similar

enough to hPIV-1 to act as a vaccine, but different enough to have never been

associated with a human disease, according to Karen Slobod, MD, associate

member of the department of Infectious Diseases. Slobod is the lead author of the Vaccine report.

Pre-clinical studies by the St. Jude team proved that intranasal SeV

vaccine can protect against the human croup virus. The results of the study in

nine healthy adults demonstrated that the SeV vaccine was safe and well

tolerated. None of those vaccinated experienced any significant reactions,

such as respiratory symptoms or laboratory abnormalities.

This FDA-approved Phase I trial was initiated in adults as a first step,

prior to future testing in children and then infants-the ultimate target

population, said Jerry Shenep, MD, member of the department of Infectious

Diseases and a co-author of the paper.

 "The St. Jude team based the vaccine on SeV for two reasons," said Allen

Portner, PhD, member of the department of Infectious Diseases and a co-

author of the paper. "First, it appears likely that this virus will provide

immunity against hPIV-1 in infants. Second, despite the fact that children

frequently have close contact with mice carrying SeV, there has never been a

confirmed case of SeV infection in humans."

Using a natural mimic of a human virus follows in the tradition of the

world's most successful vaccine, the smallpox vaccine, said Julia Hurwitz,

PhD, a member of the department of Immunology.

"The smallpox vaccine was based on the cowpox virus, which caused only

limited skin infection in healthy humans," Hurwitz said. "Yet it provided

lifelong protection against smallpox and eradicated this disease from the

human population in the 1970s. We hope that SeV will similarly help eradicate

hPIV-1 as a cause of childhood croup."

Other authors of the study are Jorge Lujan-Zilbermann, Kim Allison, Brita

Brown, Ruth Ann Scroggs and Chris Coleclough.

This work was support in part by NIH and ALSAC.

Source: St. Jude Children's Research Hospital