Centers for Disease Control and Prevention (CDC) Norovirus Outbreak Surveillance Network Director and National Calicivirus Laboratory Head Dr. Jan Vinjé presented the recent advances in human norovirus surveillance and status of norovirus vaccines at theLaboratory Research Division (LRD) Brown Bag conference at the RITM Auditorium on May 7, 2019.

Norovirus, previously known as Norwalk virus, is a highly contagious human enteric pathogen that causes vomiting and diarrhea. According to Dr. Vinjé the virus poses substantial morbidity, mortality, and economic burden. 

“It’s not like the virus you get once in your childhood. This is a virus with a limited immunity as far as we know. There is a significant chance you could get infections throughout your lifetime,” says Dr. Vinjé. 

When it comes to enteric pathogens, noroviruses wouldn’t be the first thing that comes up in people’s minds. However, Dr. Vinjé emphasized that noroviruses are important viral etiologic agent of acute gastroenteritis. 

In comparison to rotavirus, outpatient visits noted in a 2009 study reported that the number of illnesses are higher for norovirus and that it is associated with 20% of the cases. As for food-borne outbreaks, Dr. Vinjé highlighted that almost 50% of the cases are caused by the norovirus – “making it a major player in food-borne outbreaks.”

“It is associated with more severe outcomes which is exemplified by the number of hospitalizations and the most severe outcome by the number of deaths,” explained Dr. Vinjé as he stresses how attention should be given to this enteric pathogen.

Out of its six  genogroups,  genogroup II (GII) was mentioned as the causative agent for almost all infections in humans making up 90-95% of all the infections. The strain GII.4 has been predominant and leading cause of 50-70% of outbreaks in the past 15 years. 

The importance of norovirus surveillance couldn’t have been more emphasized as new strains (GII.2, GII.17), new recombinant viruses (e.g. P16), greater variability in children, and unusual strains in low-resource countries were reported.

Fortunately, better control measures and targeted interventions are already in the pipeline to address this concern. Dr. Vinjé mentioned that a set of protocols which can be used by laboratories and surveillance networks are already in place. He added that a novel cell culture system will help in guiding control measures, as well as improving food safety and infection control practices. Most importantly, candidate norovirus vaccines are currently under development. 

Dr. Vinjé spearheaded the Global Norovirus Surveillance Network (NoroSurv) and currently, the National Reference of Rotavirus and Other Enteric Viruses housed in the Department of Virology is part of this surveillance network.

by Allenor Enciso, Communication and Engagement Office