Vaccines protect against diarrhea virus – studies

By Gene Emery

BOSTON (Reuters) – Experimental vaccines by drug-makers
Merck and GlaxoSmithKline can prevent severe childhood diarrhea
caused by rotaviruses that kill thousands of children a year
worldwide, two studies showed on Wednesday.

Rotaviruses cause diarrhea and vomiting that last for days,
killing an estimated 600,000 children a year. Most of the
deaths are in developing countries but the disease is found
even in countries with good sanitation and clean water.

“After a long period of waiting, the time for a rotavirus
vaccine may have finally arrived,” said Roger Glass and Umesh
Parashar of the Centers for Disease Control and Prevention in
Atlanta.

An earlier vaccine, Wyeth’s RotaShield, was withdrawn in
1999 after it seemed to increase the risk of intussusception, a
sometimes-fatal bowel obstruction.

The new studies published in this week’s New England
Journal of Medicine showed that intussusception is not a
problem with the new vaccines, Rotarix from GlaxoSmithKline Plc
and RotaTeq from Merck & Co. Inc..

Rotarix, which tends to be more potent and requires only
two oral doses one or two months apart, cut the hospitalization
rate from diarrhea from any cause among 63,000 young children
in 11 Latin American countries and in Finland by 42 percent.

RotaTeq does not grow as well in the human gut so it has to
be given in three doses, each separated by at least a month. It
cut the hospitalization rate for all types of diarrhea by 63
percent among 68,000 children before their first birthday.

In confirmed cases of rotavirus illness, 12 Rotarix
recipients developed a severe infection compared to 77 in the
placebo group. In the RotaTeq study, only 6 of 28,646
vaccinated children had to be hospitalized because they were
infected by one of the rotavirus virus strains used in the
vaccine, compared to 138 of 28,488 youngsters who got placebo.

Also, “RotaTeq reduced the number of lost work days (for
parents) from rotavirus by nearly 87 percent, a welcome benefit
with clear economic implications for families,” Glass and
Parashar said in a New England Journal of Medicine editorial.

Rotarix prevented 85 percent of severe rotavirus illness
and RotaTeq succeeded 98 percent of the time, but the
difference in the effectiveness may be due to differences in
the way the severity of the illness was classified or the fact
that Rotarix was studied in poorer families.

Neither vaccine has been licensed in the United States,
although Rotarix was approved last summer in Mexico.

The drug companies funded and coordinated their respective
studies.