Two New Vaccines Against Viral Diarrhea

Filed in archive Drugs, Vaccines and Therapeutics on January 9, 2006

According to the CDC, Rotavirus is the most common cause of severe diarrhea among children, resulting in the hospitalization of approximately 55,000 children each year in the United States and the death of over 600,000 children annually worldwide.

Although the US FDA approved the live oral live virus vaccine (Rotashield) for use in children in 1998, this vaccine is not recommended for infants due to a strong association between Rotashield and intussusception (bowel obstruction).

Clinical trials, however, indicate that two new oral vaccines, virtually eliminated the most severe cases of rotavirus, are safe and showed no adverse side effects such as intestinal blockage, or intussusception. Both are both live oral vaccines intended to be given to infants at the same time as their immunizations for diphtheria, pertussis, and tetanus, but they differ in their approaches, strains, and formulations.

Rotarix, from GlaxoSmithKline:

• monovalent


• derived from the most common human rotavirus strain, G1P[8], that has been attenuated by serial passage


• administered in two oral doses one to two months apart.

Rotateq, from Merck:

• pentavalent


• based on a bovine strain, WC3, naturally attenuated for humans


• three oral doses are required, with at least a month between doses.

The results of both clinical trials are published in this week's New England Journal of Medicine. The Editorial compares the two clinical studies, and provide more in-depth analysis on The Promise of New Rotavirus Vaccines, urging the need for further trials:

...a number of issues remain to be faced before rotavirus vaccines can realize their full potential. For the developed world, issues of price, acceptability, public awareness, and fear of intussusception will need to be addressed before the effect of this vaccine will be fully felt. The key question for the global community will be to determine whether these vaccines work equally well among the poorest children in the developing world. Live oral vaccines must replicate and be processed in the infant's gut in order to induce a good immune response and be protective.

With the Global Alliance for Vaccines and Immunization, the World Health Organization, and the Bill and Melinda Gates Foundation backing up these studies, safe, effective and affordable rotavirus vaccines may finally be within reach.

Sources: New England Journal of Medicine, East Virginia Medical School