H and I have been getting together twice a week for years now, sometimes with a third family, for co-schooling. We have always tried to minimize the number of skipped days, so that the kids' education doesn't get too interrupted and so we can keep a steady routine; and that's felt more important as children have grown into high school students.
A long time ago, we made up our minds that there was no point in skipping school days together because of rhinovirus symptoms. Colds last a long time, and when you only go three days without seeing one another, chances are good we already passed it on. We also don't typically skip school for conjunctivitis, head lice, or strep (once the antibiotics have started).
We do typically skip school if someone has been vomiting recently. Nobody wants to pass that along! But we had always lacked an algorithm for deciding when to resume getting together after symptoms have disappeared.
Part of that has been that our families have different attitudes about GI illness. This is in turn because we tend to experience GI illness differently.
H and her kids always seem to be hit very hard by any stomach bug, a couple of times every winter. The children need to be rehydrated a teaspoon at a time and can't keep anything down for days, everyone is miserable, and her older kids are petrified of catching the bug. So in H's family, as soon as someone shows sign of illness, H and her older kids go into high-alert transmission prevention:
- Well people isolate themselves to a different floor of the house with its own bathroom
- The ill person uses only one bathroom
- No well people except H cares for sick people, unless she is too sick to do it herself
- Ill people and the person caring for them don't cook or prepare food
- Everything is laundered with bleach on the sanitize cycle
- Dishes are washed on the sanitize cycle
- Surfaces are disinfected as soon after vomiting as is practical using a wet bleach solution left to sit 5-15 minutes
- Until the twin toddlers are recovered, they stay on the main level of the house only
- H sleeps with the twin toddlers on a blanket on the wood floor so all sleep surfaces are bleachable or washable in the machine
- H personally supervises all toddler vomiting, toileting and handwashing
- Young recently-potty-trained children must wear diapers
- Vomit basins are disinfected with bleach between episodes
- Hard toys that children had while sick are disinfected with bleach
In other words, it's really important to H and her kids that they try as hard as they possibly can to avoid passing the bug to each other.
Whereas, in my family, my kids tend to throw up a couple of times and sleep a bit more, and then feel pretty good in between vomitings. And I know that you have to work hard to avoid transmitting, say, a norovirus in close quarters. So my attitude has tended to be more like, "We are all doomed anyway; let's just get this over quickly." I tend to put the sick kid on a couch with an iPad and a bucket and go about my business, but with extra handwashing and a supply of saltines, applesauce, and Gatorade on hand.
I suspect that over the years this difference in attitude has caused H to regard me, privately, as astonishingly lax; and me to regard H, privately, as bordering on obsessive. (She'd be the first to tell you that the obsession originates not in her but in her older kids, who voluntarily isolate themselves and compulsively wash their hands until the danger appears to be past.)
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One thing that's guaranteed to happen every time: a phone conversation between me and H where we wonder, "Is it safe for us to get together or should we skip another school day?"
We recently passed an apparent norovirus around between our families, and got to talking about developing an algorithm for figuring out how long we should wait, after someone has GI symptoms and then they resolve, before getting together again. The problem is, we had a lot of unanswered questions.
We do want to avoid passing the bug to people who are still well, but what is a reasonable time to wait? We knew that people can pass noro to each other for weeks, and it truly isn't feasible to skip our school days together for more than a few weeks -- especially when the risk of transmission drops fairly low. Also, is it even possible to prevent transmission? Maybe waiting an extra half-week will make a difference, but on the other hand maybe we would have been doomed anyway. And given that we get together every 3 or 4 days, has everyone in one family already been exposed before one kid starts throwing up in the middle of the night? And given our asymmetric attitudes toward illness, should we have an asymmetric algorithm for infection prevention? We were not sure.
Fortunately, this blog has its own epidemiologist on retainer: commenter ChristyP, also known as my friend from high school and college, also known as Prof. Christy Porucznik of the Department of Family and Preventive Medicine at the medical school at the University of Utah.
I sent Christy an email with the subject line "Practical Epidemiology Question!" and included data about our get-together schedule. She replied (the following has been lightly edited, and two emails have been combined, for blog-reading clarity):
Contagious period (= time of viral shedding in stool) for norovirus can be up to 6 weeks (Centers for Disease Control website says 2 weeks or more, my advisor in grad school was doing a trial and it was on the order of 6 weeks in some people).
I'd go for a similar algorithm as used in public schools and daycare centers which is exclusion from school (in your case, attempt to isolate the sick person) for 24 hours after last vomiting.
Incubation period is 24--48 hours (median of 36 hours), and if an exposed household has gone 2 incubation periods without a new case then you are likely home-free. If practical within a household, you might be able to reduce transmission by reserving one bathroom for use of the sick person and try to keep everyone else out of there. In your situation, I wouldn't see a reason to exclude a kid who wasn't ill from co-schooling unless s/he had a massive exposure (nearby when a sibling vomited or participated in cleanup).
In a norovirus situation parents are likely doomed, but also able to practice Excellent Hygiene Behavior. I would even Clorox-wipe your glasses, wash your face and rinse out your mouth in addition to any exposed skin if you were nearby someone vomiting. If you can, you might even employ a vomit shirt (or lab coat) so that you don't inadvertently carry the particles from the room of doom to the rest of the house. The infectious dose is SO LOW. It's on the order of 10 virus particles and they aerosolize! A really intense family hygiene suggestion is to make sure that toothbrushes are in a closed container so that they are not inadvertently contaminated by aerosolized evacuations generated in the same room. Also close the toilet lid. Every time. But that doesn't help with people actively engaged in generating biological aerosols by vomiting.
It is possible that one is shedding virus before the dramatic GI symptoms start, but the time that a person is most contagious is when s/he is experiencing vomiting and/or diarrhea, which is thankfully short. The virus is relatively hardy and can persist on surfaces longer than one might expect (hence long outbreaks on cruise ships and in hotels). Changing towels frequently is probably a good idea....
FWIW, there are several strains of norovirus, and immunity to the strain you most recently had lasts only about 12 weeks.
When I teach Infectious Disease Epidemiology I say that caring for someone with norovirus is the surest way to see your own future. I will also share here one of my favorite bits of advice to share at La Leche League meetings, which is that when your child is still in the vomiting-every-hour phase is when you should prep some snacks that s/he can grab from the fridge the next day, when the child is feeling fine but starving and you are the sick one.
I went back to H and issued my judgment about the correct algorithm, using the more conservative estimate (48h) for the incubation period.
Co-Schooling Gastrointestinal Illness Algorithm
Rule 1: If anyone gets GI symptoms, skip the next scheduled co-schooling day.
We only go 75 hours between meetings, and it takes 96 hours to find out if the other household has escaped.
Rule 2: When GI symptoms appear in the first family:
- If we last met more than 48 h ago, consider the second family unexposed.
- If we last met less than 48 h ago, consider the second family possibly exposed.
- But if the second family makes it to 96 hours with no symptoms, consider them again to be unexposed.
This rule doesn't bear directly on co-school cancellations, but it does help the second family decide what precautions would be prudent.
Rule 3: If everyone in one family has been sick, we can return to co-schooling after they have all gone 24 hours without symptoms.
Rule 4: If only some people in one family have been sick, we can return to co-schooling when the sick family has gone 96 hours without symptoms.
This is under the assumption that the not-yet-sick could be incubating the illness and could show symptoms at any time, combined with a strong preference to avoid exposing the unexposed.
Rule 5: If there are some who have been sick and some who have not been sick yet in BOTH families, we can get together after
- my family has gone without symptoms for 48 hours, and
- H's family has gone without symptoms for 24 hours.
The asymmetry is because H's family is more willing to try to avoid exposing family members; as soon as one person in my house gets sick, I assume we're all going to get it anyway, so I don't care about skipping school to wait out an entire incubation period. H, however, does think it worthwhile to try.
Rule 6: If unexposed people are to meet at a house where some have been sick within the past couple of weeks, we must aggressively disinfect surfaces they might reasonably come in contact with.
This means the kitchen, first-floor bathroom, first-floor light switches and doorknobs and the like; if the very young children haven't all been sick already, then the hard toys too. Older unexposed people should take responsibility for themselves to practice good handwashing and the like.
Rule 7: When recovered people first meet at an unexposed household, the whole family should shower or bathe before coming and wash hands on arrival.
This sounds like it should go without saying, but it's worth remembering since our younger kids don't ordinarily bathe more often than once a week or so in the winter because of dry skin.
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In addition to the rules for get-togethers, there are two best-practice guidelines, to be followed if practical:
Guideline 1: To limit spreading the virus to public areas in the house, consider isolating sick people to a single bedroom and bathroom upstairs that is not used often by guests.
Because norovirus can persist on surfaces for weeks, the best practice is to keep it off those surfaces in the first place -- especially the ones guests and visitors are likely to use.
Guideline 2: Carefully supervise young children's toileting for 2 to 6 weeks after they have been ill.
They need to be monitored to make sure they wipe, wash hands, put their pants back on, and don't leave used potties lying around.
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It's too late for these rules and guidelines to save us in the current round of noro, but we can keep this in our back pocket for the next time.
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