Norovirus: because everyone enjoys violent vomiting and diarrhea, right?
Tips to navigate the "stomach flu" including if someone is sick in your house, and some other updates
Happy Tuesday everyone! Before we get into an infectious disease state of affairs, I know some of you have heard whispers and have questions.
Yes, it is true, I am no longer volunteering with Unbiased Science.
It’s been nearly 4 years of content creation for the weekly podcast, daily social posts, biweekly newsletter for that team, and being the co-host of the brand in entirety. While I was hopeful that a business plan would be implemented that would allow me to continue to contribute to those efforts, ultimately that didn’t come to fruition, and the goals of the company (which I did not have ownership in) did not align with my goals of science communication. My desire to do science communication has always been from passion to help people better navigate the world, and that’s what I’ll continue to do.
Ultimately, volunteering 40+ hours a week creating content for those pages was not sustainable for my physical or mental health, especially because I have a full-time [paying] job in life sciences biotech that is my primary priority!
What does that mean for you all?
Well, if you follow Unbiased Science and listen to the podcast, it means that I no longer will be on the podcast, creating content for the podcast or social pages. It also means I will no longer be writing or publishing their Substack newsletters, although I am sure someone else will move into that role.
If you came to ImmunoLogic through Unbiased Science, rest assured, I will still be writing THIS newsletter here. It also means I will have more time to do science communication here!
If you are on a paid subscription for Unbiased Science’s newsletter and feel inclined to upgrade to a paid subscription here ($5/month), I always appreciate support if you can afford it, but my content here will always be free.
I also have my personal social channels: Instagram, Facebook, Threads, and LinkedIn, so be sure to follow me on whichever platform you prefer.
I am also involved with several other science education organizations, which I will be investing more time in.
ImmunoLogic, my personal LLC for science consulting, where I offer the same services that I was previously with Unbiased Science.
American Lyme Disease Foundation, a volunteer non-profit that was formed in the 1990s by infectious disease clinicians and scientists who were frustrated by misinformation about Lyme and other tick-borne diseases. I have been the Executive Director there since 2023, and I am *very* excited about a new website unveil coming later this week that I have been working on for the last several months.
Lyme disease is rife with misinformation, and as someone who grew up adjacent to Lyme, CT, lived in the epicenter of Lyme my entire life, and did my PhD dissertation research on Lyme immunology, dispelling harmful misinformation on this topic has always been a passion project of mine.
I will also be collaborating with other organizations with similar goals to make science more accessible and understandable. It also means that I will be able to have time to GUEST on podcasts that others host as well as publish more. I was even on a live radio show last week to discuss my article on chlormequat, the EWG, and genetic engineering more broadly.
To that end, the best way to get in touch is this email address: drandrealove@gmail.com. I can’t guarantee I will reply to every email, but I will do my best! You can also submit a request through my website.
And with that, let’s get into some science.
Norovirus is once again sweeping the country
Noroviruses are the most common cause of acute gastroenteritis (inflammation of the Gl tract) are the noroviruses. Norovirus outbreaks can occur throughout the year, but are most common during winter: which means, right now! Currently, norovirus test positivity rates are between 12 and 13%, with case rates especially high in the northeast. This is not quite as high as the rates this time last year, which peaked at around 15%.
While sometimes called “stomach flu”, norovirus is not remotely related to influenza viruses. Noroviruses are in the calicivirus family, which are non-enveloped viruses. Viruses are classified according to their structure and composition, which, if you recall from my newsletter here, includes their viral genome and the protein capsid. Viruses that only contain those pieces are considered non-enveloped, whereas viruses that have a lipid membrane surrounding the protein capsid are enveloped.
Non-enveloped, or naked viruses like noroviruses tend to be more virulent than enveloped viruses. This is because they are more resistant to the elements and can withstand heat, humidity changes, and many disinfectants. In addition to the noroviruses, other non-enveloped human pathogens are enteroviruses, adenoviruses, and rhinoviruses.
Most hand sanitizers are ineffective at inactivating non-enveloped viruses like noroviruses
Alcohol-based hand sanitizers work to inactivate viruses by a few mechanisms, based on the active ingredient: either ethanol or isopropanol (2 different alcohols).
Disruption of Lipid Membranes: Alcohol disrupts the lipid (fat) membrane of enveloped viruses, which is essential for these viruses to attach to and infect host cells. Alcohol molecules intercalate into the membrane, causing it to break apart, which renders the virus non-infectious.
Denaturation of Proteins: Alcohol also denatures proteins, which means it unfolds and inactivates them. Viral proteins, including those required for attachment and entry into host cells are susceptible to denaturation. When these proteins lose their three-dimensional structure, they lose their function, effectively neutralizing the virus.
Disruption of Viral Capsids: In non-enveloped viruses, although more resistant, alcohol can still have some effect, particularly at higher concentrations. The capsid, a protein shell that encloses the viral genome, can be partially disrupted or denatured by alcohol, although this is less efficient than the disruption of lipid membranes.
Most commercial hand sanitizers range between 40-80% alcohol content. For effective inactivation of norovirus (and other non-enveloped viruses), you need 95% ethanol. As such, hand washing with soap and water is the preferred method for proper hygiene among the general public, especially if you’ve been in contact with fecal matter.
Detergents in soap form micelles (think of these like little fat cages) around pathogens which trap them and allow them to be washed away when rinsing with water.
What about cleaning surfaces?
Don’t panic - there are some chemicals that are effective for disinfecting surfaces that may be contaminated with norovirus:
Bleach (Sodium Hypochlorite): Bleach is your number one option and is the most effective disinfectants against norovirus. Bleach works by denaturing proteins and disrupting viral RNA, much more effectively than alcohol. A solution containing 5-25 tablespoons of household bleach per gallon of water is recommended. The exact concentration may vary based on the surface and situation.
Other options if bleach isn’t available:
Hydrogen Peroxide: Hydrogen peroxide at a concentration of at least 3% can be effective against norovirus. It acts as an oxidizing agent, damaging essential components of the virus.
Quaternary Ammonium Compounds: Also known as "quats," these compounds can be found in household cleaning products and some types of disinfectant wipes. They can be effective against norovirus but often need to be used at higher concentrations. (Note: this includes benzalkonium chloride, which is not as effective as bleach and requires longer contact time and higher concentration).
Accelerated Hydrogen Peroxide (AHP): This is a more potent form of hydrogen peroxide and is effective against a broad range of pathogens, including norovirus.
Phenolic Disinfectants: Some phenolic disinfectants can be effective against norovirus. Phenols are specific classes of alcohols with unique properties, and you’ll typically find these used in healthcare settings.
Alcohols at Higher Concentrations: While regular alcohol-based hand sanitizers are not very effective against norovirus, higher concentrations of alcohol in certain disinfectants (95%) can have some efficacy. However, their use is more limited compared to other options like bleach.
UV Light: Ultraviolet light, particularly UV-C, can be effective for surface disinfection against norovirus, although it's more commonly used in healthcare settings than in households.
If you aren’t sure what you have is effective, check the EPA list of antimicrobials for norovirus.
Norovirus is also extremely contagious.
Someone can get infected after being exposed to fewer than 20 viral particles. That’s why it spreads phenomenally easily through person-to-person contact, fecal-oral, contaminated surfaces, and food/water sources.
Foodborne norovirus is transmitted a few different ways: first, through shellfish or seafood that was harvested from waters that are contaminated with human waste, or through poor personal and food hygiene practices, where an individual directly contaminates food.
Another fun tidbit: you can shed virus in your stool for several weeks after symptoms disappear, and since it spreads so easily and the virus is so stable, it means that infections can rage in communities. Indeed, an outbreak in December was traced back to a sushi restaurant in North Carolina, where over 240 people reported falling ill after dining there. Since a thorough deep clean following temporary closure, no subsequent issues have been reported.
Illness caused by norovirus is fast and furious
Symptoms develop between 12 and 48 hours after exposure and are typically violent. They include nausea, acute-onset vomiting, watery, non-bloody diarrhea, and abdominal cramps. Fatigue, muscle aches, headache, and fever can also be present.
Now, for all you reading and thinking, jeez, what next?! There is some good news.
Illness for most is usually mild, & symptoms last 1-3 days. However, norovirus can be particularly serious for young children and older adults. Children under 5 years old and adults aged 85 years and older are more likely to have an outpatient or emergency department visit than people of other ages.
It is estimated to be responsible for nearly 1 million pediatric medical visits every year in the US, and can be a serious cause of morbidity and mortality.
By 5 years of age:
1 in 110,000 will die from norovirus
1 in 160 will be hospitalized
1 in 40 will go to the emergency department
1 in 7 will go to an outpatient clinic
It is the number 1 cause of foodborne illness, fourth leading cause of foodborne illness-related death, and is responsible for 58% of foodborne illness. Globally, norovirus causes around 685 million cases of illness every year. In the US, it is estimated to cause up to 21 million cases of gastroenteritis annually.
How can you protect yourself and others if someone at home has norovirus?
Unfortunately, there is no vaccine for norovirus and treatment involves supportive care. But if someone at home has norovirus, it isn’t a guarantee that everyone else will get it. You can take steps to reduce the risk.
Hand hygiene, especially in any common areas and particularly in the bathroom and kitchen spaces. Soap and water is king here. This is especially important after using the toilet, after changing diapers (if applicable), and before eating, preparing, or handling food.
Food hygiene is essential. It goes without saying the sick individual should not be touching common food or prepping food for others in the house, and, if possible, should not be in the vicinity when food is being prepared. You should also not prepare foods for up to 3 days after your symptoms subside. However, additional measures can also be taken. Thoroughly wash fruits and vegetables before preparing and eating them, especially if eaten raw. Ensure seafood is washed and cooked thoroughly: norovirus can survive “searing” and quick “steaming” and temperatures up to 140F. Any foods that are potentially contaminated from the sick individual should be discarded. You can also consider wearing clean gloves while handling food or interacting with a sick individual.
Disinfect surfaces immediately. Any surfaces which have been in contact with vomit or fecal matter should be disinfected as soon as possible. Use a chlorine bleach solution with a concentration of 1000–5000 ppm (5–25 tablespoons of household bleach [5.25%] per gallon of water).
Thorough and prompt laundry. Anything: clothing, linens, etc., that may be contaminated should be washed. Minimize disturbance of potentially contaminated fabrics (remember: 20 viral particles can infect someone), wear gloves while handling and wash hands thoroughly after touching. Wash items in the washing machine with the highest cycle length and machine dry (for additional heat sterilization) afterward.
Caring for the sick individual. If the individual is actively vomiting, having diarrhea, and may not have the best hygiene for whatever reason, you can consider wearing a high quality mask around the house when you are in contact with them. This will reduce the likelihood of particles floating around that may contain virus. You can also consider wearing gloves if providing care for them, and always make sure to wash your hands extra thoroughly after interacting with them. You may also consider changing out of clothing you wore when in contact with them so you aren’t potentially carrying viral particles elsewhere around the house or out of the house.
And if you do inevitably get sick, I wish you all the best! I have had norovirus once (thanks to my adorable but germ-infested niece), and it was one of the most unpleasant things I’ve ever experienced. Just remember: while you are balled up in pain, cursing whoever infected you, know that the chaos will be over with in a couple of days.
Thanks for joining in the fight for science!
Thank you for supporting evidence-based science communication. With outbreaks of preventable diseases, refusal of evidence-based medical interventions, propagation of pseudoscience by prominent public “personalities”, it’s needed now more than ever.
Your local immunologist,
Andrea
Ahhh the virus that leveled my sister’s baby shower 9 years ago. Her friend’s mom made the sandwiches that decimated all of our digestive systems within 24 hours. We found out she had been on a cruise earlier that week where there was a minor outbreak. 0/10 recommend. 😆
How long can norovirus live on a surface if not properly disinfected? Appreciate this article!