Norovirus: Vaccine for Cruise Ship Virus? Hope For Future Treatment?

Vaccine may prevent “cruise ship virus”, “winter vomiting bug”
Researchers may soon roll out a vaccine to prevent people from catching the norovirus, the “winter vomiting bug” or “cruise ship virus,” blamed worldwide for outbreaks on cruise ships or on planes and in hospitals, schools and prisons during the winter.

That is, if the researchers at the Baylor College of Medicine in Houston, Texas, are able to improve an experimental vaccine developed for the first time against the highly contagious virus that brings sudden cramping, vomiting and diarrhea to three million people across the world every year.

The vaccine has been shown to halve the chances of catching norovirus, called the “cruise ship bug” after repeated outbreaks have plagued the cruise industry for decades.

But norovirus outbreaks also occur often in other closed or semi-closed communities like schools, hospitals, dormitories, prisons and overnight camps, where they are spread rapidly by person-to-person transmission or through contaminated food.

In 2005, a norovirus epidemic broke out among Hurricane Katrina refugees housed in the Reliant stadium in Houston, Texas.

In many countries it is also known as the “winter vomiting bug” when it strikes millions of people during the winter, as they spend more time indoors.

The experimental vaccine, given in two doses three weeks apart via a nasal spray, brings hope that such outbreaks can be controlled or prevented in the future.

“This is the first demonstration of protection in humans against what is a widespread and often serious illness and is a big development for the field,” said Robert Atmar, M.D., of Baylor College of Medicine and the study’s principal investigator.

The study was a multi-center trial undertaken by a consortium of research centers whose members are the Johns Hopkins University, University of Maryland, Cincinnati Children’s Hospital, SNBL Clinical Pharmacology Center, Inc., The EMMES Corporation and the Baylor College of Medicine. It was published in the New England Journal of Medicine on Dec. 10.

No safety issues were witnessed in the study and the side effects noted were mild: stuffy nose and sneezing.

Earlier studies showed that people inherit a susceptibility to being infected by the norovirus. Other studies showed that the infection only brings an incomplete and temporary immunity.

In this most recent study to test the experimental vaccine, Dr. Atmar’s team gave 98 people—all of them bearing the FUT2 gene that makes them more susceptible to norovirus—either the vaccine or an inactive placebo.

Three weeks after the second dose—time enough for their immune system to respond—both groups of participants were exposed to the norovirus.

The study showed that the participants who received the vaccine were 70 percent less likely to suffer the cramping, diarrhea and vomiting associated with the norovirus than those who were given a placebo.

While some vaccinated participants still contracted the virus, they experienced symptoms a third milder than those who got the placebo.

First steps
These results are an “important step toward preventing the disease,” Dr. Robert Frenck, MD, a professor of pediatrics who researches noroviruses at the University of Cincinnati told WebMD on Dec. 10.

“This is early, but it’s encouraging,” said Frenck, who was not involved in Atmar’s study.

The vaccine could be especially useful for populations such as soldiers or the elderly, he said.

Dr. Josh Bloom, PhD, Director of Chemical and Pharmaceutical Sciences at the American Council on Science and Health said he was excited over the experimental vaccine.

“I think the vaccine’s efficacy rate needs some improvement,” he said on an article on the ACSH’s site, “but since the virus leads to 800 deaths in the U.S. annually—mostly among the elderly—and about 100,000 hospitalizations, any advances in preventing this illness will be welcome news.”