Rotavirus cases are on the rise. Here's what to know about the highly contagious disease.

Rotavirus, the highly contagious disease that can cause severe vomiting and diarrhea in babies and young children, is on the rise on Long Island, the rest of the metropolitan area and nationwide. Doctors warn children infected can get so dehydrated they may need to go to the hospital for intravenous fluids.

Earlier this year, federal health officials dropped the rotavirus vaccination from the list of recommended childhood vaccines, a move that infectious disease experts said could cause fewer parents to get the vaccine for their babies in the coming years.

Before 2006, when the latest vaccine became available, rotavirus resulted in up to 70,000 hospitalizations and 20 to 60 deaths a year among children, according to the National Foundation for Infectious Diseases.

Newsday is providing answers to a range of questions about the disease.

Why is there a surge in rotavirus cases right now?

Data from the Centers for Disease Control and Prevention shows the percentage of positive rotavirus cases in the Northeast was 9.6% for the week ending April 11. That’s higher than the last two years around the same time. Experts said rotavirus usually appears in the spring but there are several factors that could lead to a rise in cases this year.

"During the long winter, kids spend more time indoors,” said Dr. Asif Noor, chief of pediatric infectious diseases at NYU Langone–Long Island, adding he has seen an increase in cases across the hospital system that mirrors the regional and national trend.

"Rotavirus comes on pretty quickly and spreads pretty quickly," Noor said.

 Fewer parents are getting the vaccine for their children, he said.

What are the symptoms of rotavirus?

Vomiting and diarrhea are the main symptoms, along with fever and stomach pain. Identifying signs of dehydration among babies can sometimes be challenging. Parents and caregivers should look out for lethargy, fewer wet diapers, dry and cool skin as well as crying without producing tears.

How is rotavirus spread?

The virus is passed through an infected person’s stool, which can be present in microscopic amounts on hands, hard surfaces and even food, according to the CDC. Family members can easily pick up the virus from children in the home.

"It can be found in your stool two days before your diarrhea onset and up to 10 days after your initial symptoms,” said Dr. Sharon Nachman, chief of pediatric infectious diseases at Stony Brook Children’s Hospital. "So you go back to school, go back to work, the kids go back to day care and they are still infectious.”

How can I protect my child and myself from rotavirus?

Good hand hygiene can help but it’s not enough to stop the spread of the disease, the CDC said. The rotavirus vaccine, which is dispensed in oral drops, is given two months after birth and then given one or two more times before the age of 6 months, depending on the formulation.

Nachman said the rotavirus vaccine is 98% protective against severe illness, and 96% protective against hospitalization and emergency department visits.

An increase in vaccine hesitancy and the Department of Health and Human Services decision earlier this year to leave it off the list of recommended vaccines for children may cause a "catastrophic” number of cases next year and beyond, she said.

Is rotavirus really a threat to my child’s health?

"This needs to be taken very seriously,” Noor said. "Parents need to be aware that babies and toddlers can become dehydrated very quickly so they should not wait. Start oral hydration at home and if the baby is still throwing up, seek medical attention ... worldwide gastrointestinal illnesses, including rotavirus, are still the number one killer of children.”

By Lisa L. Colangelo

lisa.colangelo@newsday.com@lisalcolangelo

Lisa joined Newsday as a staff writer in 2019. She previously worked at amNewYork, the New York Daily News and the Asbury Park Press covering politics, government and general assignment.