A: While we can’t predict the future… it would take a scientific miracle for everything to be hunky-dory by Thanksgiving here in the States & make “Thanksgiving as usual” a reality. You might as well plan on a pandemic Thanksgiving now–because it will take some planning to safely get together with members of your family for the Turkey Feast.
If you want to get your family together, think about ways to reduce the risk. There are two general ways to approach harm reduction. First, do what you can to reduce the risk of transmission, assuming someone at your gathering brings COVID along as an uninvited guest. That means wearing a mask, keeping it short, improving the ventilation, and of course (always) washing hands.
Since our traditional turkey day involves a relatively long, formal, indoor meal, it’s tough to think how we will wear a mask and keep it short. So, let’s talk about the other way to reduce risk: ensure no one present has COVID in the first place by quarantining before the visit. Let’s revisit the timeline of COVID-19 infection for a little help, using Thanksgiving as an example.
I want to have Grandma over for Thanksgiving dinner on Thursday, November 26th–and I want it to be the traditional Thanksgiving sit-down family meal, and I want to be 100% sure that no one gives her COVID.
The path to having grandma over safely is to make sure that everyone coming to my Thanksgiving table has NO EXPOSURES for the whole 14 days before November 26th. The magic day to start a personal pre-holiday quarantine is Friday, November 13th. Everyone in my household, and all my Thanksgiving dinner guests, will have to abstain from any possible exposures–at the grocery store, the office, or school–starting on the 13th. This gives us all the full 14 days to observe whether any symptoms have arisen before we are all together for the traditional Turkey Feast.
In addition, just to be sure that we aren’t harboring an asymptomatic infection, we might go get tested for COVID. The best timing to do this would be as late in the 14-day window as possible and still expect to have results back by the 26th. Right now, in my area, I hear it takes 3 days to get test results back from the community testing center. So we will be tested on November 22nd, leaving a bit of a window for testing to slow down on the holiday week.
Variation 1: But if the average incubation period is 5 days, why isn’t 5 days of quarantine enough?
A: Because 5 days is just the *average*. That means half of people who go on to have symptoms have an incubation period that is longer than 5 days. And some people never have symptoms.
Example: Uncle John has to go to work in person up until November 20, which gives him 6 days to isolate. Uncle John is exceptional in so many ways, and it’s *entirely* possible that he is experiencing an incubation period of more than 6 days. Uncle John quarantines for 6 days before coming to Thanksgiving dinner on Nov 26. He has no symptoms at all. But on November 29th–day 9 for him–he experiences a dry cough and a fever and realizes that the whole family was exposed to him when he was pre-symptomatic, but contagious. CDC estimates that 50% of transmission occurs before symptom onset. 5 or 6 days of quarantine is not enough, even though the average incubation period is 5-6 days.
Variation 2: Can testing on a certain day offer a shortcut to the quarantine period?
A: Not really. Testing immediately after we may have been exposed is not useful at all because it takes some time for the virus to replicate in our nasal passageways following an exposure. The *best* timing for an accurate test is dependent on the same uncertainty in the incubation period, which means that shortcutting with a test is not very reliable.
Example: My brother and sister-in-law, Janet and Fred, are bringing the twins. They’re driving in from a few states away. They plan to go to school & work in-person up until Nov 18, get tested on Nov 21, and leave for our place on Sunday the 22nd. By the time they arrive at my house on the 24th, they should have their test results. They figure if they’re negative, we’re all good. Right? WRONG! Check out this timeline:
Day 0, Nov 18: Kids exposed to COVID at school.
Day 3, Nov 21: Test day; kids are incubating.
Day 5, Nov 23: Kids become contagious but asymptomatic; Fred and Janet are exposed, and begin incubating their secondary infections.
Day 6, Nov 24: Test results returned negative. Arrival at my house. Mild symptoms emerge in the kids.
Day 8, Nov 26: Fred and Janet begin asymptomatic shedding. Thanksgiving dinner occurs.
Day 11, Nov 29: Fred and Janet become symptomatc with dry cough, fever, and GI problems.
If it turned out that the kids were exposed on their last day of school before they left and they incubated for the typical 5-6 days, the virus would be just starting to make lots of copies of itself in their nasal passageways when they were tested. There probably would not yet be enough virus in there for the nasal swab to find, and a false negative test is likely.
Meanwhile, Janet and Fred were truly not infected yet at the time of the test, but the kids start shedding virus in the minivan on the way to my place! The kids have a bit of a sniffle when they arrive, but Janet and Fred aren’t laid flat with fever until November 29–after they’re back home. Grandma was exposed, even though Janet, Fred, and the kids ALL tested negative. Shortcutting using a well-timed test is rolling the dice on whether your incubation period is average–or not.