Recently, PLOS released a massive collection of articles, blog posts, and materials related to norovirus. If you want the most complete and up-to-date picture of what noroviruses are doing around the world, click the link and enjoy some first-rate research!
Several NoroCORE Collaborators were involved in this compilation of works, as well as other researchers from all over the globe.
The main focus of this expert group was to assess the global burden of norovirus and to consider the prospect of a norovirus vaccine and how to best use this tool if one or more of the vaccines currently in development become available.
Here are just a few of the highlights:
- Norovirus is the #1 cause of diarrhea in the world, responsible for about one out of every five cases. (Rotavirus used to be the most common cause of diarrheal disease in young children, but since the advent of the rotavirus vaccine, this virus is much less prevalent.)
- Based on computer-based modeling, norovirus is believed to cause around 699 million illnesses and 219,000 deaths each year around the world.
- Norovirus costs the world over $60 billion US dollars each year ($86 per illness on average), with only about 4 billion of this coming from healthcare costs, and the rest from costs to society (such as lost productivity from people not being able to go to work).
- Most of this economic burden comes from caring for young children, but the most expensive group to treat for norovirus is the elderly.
- In developed countries, norovirus outbreaks most often occur in healthcare facilities, such as nursing homes.
- Last but not least, norovirus is the most common cause of foodborne illness in the world.
These impressive statistics underscore why NoroCORE exists and why effective prevention and control strategies for the virus, as well as more research, collaboration, and outreach are so important. Since the virus is so ubiquitous, it is difficult to target just one or even a few groups for intervention strategies. One prevention strategy highlighted in the collection that stands to make inroads is a norovirus vaccine, and there are a few in development.
Making such a vaccine requires a deep understanding of our immunity and susceptibility to norovirus and the ability to assess whether these vaccines are effective. For example, did you know you might be genetically resistant to infection with the most common norovirus strains because your epithelial cells (such as those that line your gut) and your mucosal secretions (such as your saliva) do not express certain carbohydrate-based structures? (Now, with about 30 genotypes of norovirus out there, rest assured you are still expected to be susceptible to at least one of them.) And once you get over a norovirus infection, it is not always clear what protects you from your next infection with the virus, or for how long, but several factors seem to be involved. These are oversimplifications of the science (go here to read the real stuff), but hopefully it’s apparent that these are important to consider for making an effective vaccine. One recent finding that is particularly promising is that after both natural infection with norovirus and receiving a trial vaccine, humans make a heterotypic immune response. This suggests that even if you encountered a different set of noroviruses during your life than someone else, you and the other person could both be protected from an array of noroviruses if you were vaccinated. A next big question is does this carry over to children, who may not have been infected with norovirus before (and their immune systems are naïve), or to the elderly, whose immune systems are generally not as strong.
Head on over to the PLOS Norovirus Collection for more and be the talk of your friends and neighbors! Consider it as doing a good public health deed.