U.S. Cases of Infant Gut Illness Plummet After Vaccine Introduced

THURSDAY, June 20, 2019 (HealthDay News) -- In the midst of the "anti-vaxxer" movement comes more scientific proof that vaccines help save children's lives.

Researchers report that since the 2006 introduction of a vaccine against rotavirus -- a common and potentially fatal cause of infant diarrhea -- U.S. cases have fallen dramatically.

What's more, the rotavirus "season" is now much shorter, shrinking from 26 weeks each year before the vaccine's introduction to just 9 weeks' duration today.

This all "attests to the long-term benefits of the rotavirus vaccination program," concluded a team led by Benjamin Howell. He's with the National Center for Immunization and Respiratory Diseases, part of the U.S. Centers for Disease Control and Prevention.

"Rotavirus used to be the most common cause of severe vomiting and diarrhea in the United States, and it's highly contagious," noted Dr. Sophia Jan, who wasn't involved in the new research. She's chief of pediatrics at Cohen Children's Medical Center in New Hyde Park, N.Y.

Rotavirus-linked gastroenteritis can cause severe vomiting and diarrhea that typically lasts three to eight days, according to the CDC. If left untreated, severe dehydration can set in, and in the developing world, the illness is a major cause of death for babies and young children.

In 2006 routine immunization with one of two vaccines, RotaTeq and Rotarix, became standard across the United States. The vaccine is delivered by drops into babies' mouths, not by needle.

According to the CDC, "doctors recommend your child get two or three doses of the vaccine (depending on the brand of vaccine) for best protection. Babies should get the first dose at 2 months of age. For both vaccine brands, babies get a second dose at 4 months. If he's getting RotaTeq, he'll need a third dose at 6 months."

Rotavirus vaccination rates for U.S. children have plateaued at about 70%, Howell's team reported.

That's good, but still below levels in places such as Britain, where more than 90% of kids are vaccinated.

So, has routine immunization helped American kids?

To find out, Howell's team tracked rotavirus infection rates using federal data on lab tests taken before the vaccine's introduction in 2006 (2000-2006) and afterwards (2007-2018).

The results were impressive. Before the vaccine, 1 in every 4 (25.6%) lab tests came back positive for rotavirus exposure. In the post-vaccine era, that has plummeted to about 6%.

What's more, the rotavirus season is now a full 17 weeks shorter than it used to be, the study found. Infections typically occur during colder months.

The CDC team did notice one other pattern: Rotavirus cases in the United States seem to wax and wane on alternate years.

Howell's group noted that this does not seem to happen in the United Kingdom, where almost all kids are now vaccinated. So, the hope is that if more U.S. babies get immunized against rotavirus, that biennial ebb and flow would disappear.

Dr. Michael Grosso directs pediatrics at Northwell Health's Huntington Hospital in Huntington, N.Y. Reviewing the new findings, he agreed that the introduction of an effective vaccine against rotavirus -- a common cause of gastroenteritis -- has had a huge impact.

"As pediatricians, we are seeing the benefit of this immunization as cases of diarrheal disease, dehydration and consequent hospital admission have declined significantly," Grosso said.

But both Grosso and Jan warned that rotavirus, like other pediatric scourges such as measles, could make a comeback if enough parents decline to vaccinate their kids.

"The well-being of our children is at risk in the face of a rising tide of 'vaccine reluctance,'" Grosso said. "As practitioners, it is our obligation to provide accurate information about vaccine safety and the importance of immunization against rotavirus as well as other serious, preventable infectious diseases."

The new study was published in the June 21 issue of the CDC journal Morbidity and Mortality Weekly Report.

More information

The U.S. Centers for Disease Control and Prevention offers more about rotavirus.