How to Assess Your Risk After Being Vaccinated

Photo by Helena Lopes on Unsplash

Risk assessment is hard. Nearly every situation has a range of different variables that affect risk, and only some of these variables can be quantified. Others we have to estimate, and in the human brain, emotions inevitably get tangled up in the process of trying to make those estimations and come to an overall idea of how risky something is or isn’t.

“This is why medical doctors and people in public health train for years to help people understand the public health landscape and marry public health with their own individual conditions and risk,” Lucy McBride, MD, an internist in Washington, DC, said. “There’s no way an algorithm that can do that.”

Nevertheless, I did help create an interactive tool for the New York Times last week that attempted to offer a framework for assessing the risk of different situations when a person is fully vaccinated against Covid-19. Many people found it helpful while some others found it confusing or misleading. Was it actually high risk for a vaccinated person to eat dinner in a busy indoor restaurant with poor ventilation? Some who tried out the tool thought that’s what it was telling them.

To help clarify how the tool can be most effectively used, I figured I’d walk through a couple examples as sort of case studies. Before going into each one, however, it’s important to clarify that the tool’s five major components — the activity, those with you, your circle, your location, and your own health — are intended to be assessed independently of one another. Then, you take each of these independent assessments into consideration with your own risk tolerance to determine what you’re comfortable doing.

The two parts that felt particularly confusing to some people were the risk levels on the first two — what you’ll be doing and who will be there with you. If the risk level was high, did that mean it was too risky for a vaccinated person to do?

The answer is no — not necessarily. Those risk levels are not describing the risk of transmission to you personally. Rather, they describe the overall likelihood that transmission is occurring in that place. The chance that a vaccinated person will become infected with SARS-CoV-2 is extremely rare overall. But if that person is regularly in situations that have high likelihoods of transmission overall, then each risk factor accumulates over time.

There will always be some vaccinated people who do develop an infection after being exposed to the virus, even if it’s a tiny percentage. To give a preposterous example, if a vaccinated person kisses 1,000 people, their odds of infection are a whole lot higher than a vaccinated person going through a normal day that involves interaction with one or two dozen people at different places, indoors and outdoors. The more potential exposures there are, the higher the risk of infection climbs.

Is that something to worry about? For most people, no. All the FDA-authorized vaccines protect 100% against death and over 90% against severe disease and hospitalization. Any infection will likely be very mild, perhaps no worse than a cold, if that. But it still have implications for those around the sick person and possibly for the sick person’s job — hence the additional components on who is in your circle and whether you can financially afford to be even mildly sick.

To help all this make more sense, let’s walk through those examples.

Example 1: A family get-together

Let’s say this family gathering includes 20 people and is held partly indoors and partly outdoors at a home. Five attendees are children and therefore unvaccinated. All but three adults are vaccinated, and the three unvaccinated adults are young and healthy. One vaccinated adult has an autoimmune condition that requires an immune-suppressing medication. Here’s how the risk levels play out according to the New York Times tool:

What are you doing? If we choose indoors with good ventilation and no shouting, it’s mild risk. The risk goes to “high” if we say there’s shouting.

Whom will you be with? With more than 20 people, not all of whom are vaccinated, the risk is mild if following health guidelines.

Who is in your circle? There are kids and unvaccinated adults in the circle as well as a vaccinated person taking immunpsuppressing medication. Since we don’t yet have the data to know how protective the vaccines are for people taking this kind of drug, the risk is high.

Where do you live or where will you be? I chose Tarrant County, Texas, which has a “moderately high” rate of transmission.

Your own health: Let’s say you have risk factors for severe disease, but again, you’re vaccinated. Let’s say you can afford to stay home while sick if you do get infected, resulting in low risk.

Here’s the result:

Should you do the activity? Well, I would. In fact, I did: This describes exactly the scenario I was in a few weeks ago for a joint family birthday party. We wore masks while indoors and took them off outdoors. We didn’t really distance since most of us were vaccinated and we had masks. The biggest risk in the circle was uncertainty over the protection afforded by the vaccine to the person taking immune-suppressing drugs, but given that the other risk factors were mild and low, that didn’t seem a big risk overall.

Example 2: Attending a Major League Baseball game

It is possible for fans to attend MLB games this spring, with most venues operating at roughly 20% to 42% of normal capacity, depending on the location. Let’s assume you spend about 5 hours at the event, and it requires distancing as most stadiums appear to be doing.

What are you doing? It will be outdoors for 5 hours with lots of shouting: mild risk.

Whom will you be with? There are hundreds of people there, most of whom you don’t know and almost certainly many who aren’t vaccinated, but they’re distanced: mild risk.

Who is in your circle? Let’s assume you have kids and unvaccinated adults in your circle, but none are high-risk: mild risk.

Where do you live or where will you be?

If it’s a Pittsburgh Pirates home game, you’re in Allegheny County: high risk (210 cases/100,000)

If it’s a Philadelphia Phillies home game, you’re in Philadelphia County: high risk (207 cases/100,000)

If it’s a Los Angeles Dodgers home game, you’re in Los Angeles County: moderate risk (40 cases/100,000)

If it’s a New York Yankees home game, you’re in Bronx County: high risk (410 cases/100,000)

If it’s a Atlanta Braves home game, you’re in Fulton County: high risk (120 cases/100,000)

If it’s a Minnesota Twins home game, you’re in Hennepin County: high risk (166 cases/100,000)

If it’s a Chicago White Sox home game, you’re in Cook County: high risk (124 cases/100,000)

If it’s a Tampa Bay Rays home game, you’re in Pinellas County: high risk (145 cases/100,000)

Your own health: Let’s say you have no underlying risk factors and can afford to isolate if you get an infection: Low risk.

Here’s how that looks:

Many people would likely feel comfortable with going, even if the surrounding city has a high rate of transmission.

Example 3: Large indoor wedding

Assume the wedding will be held entirely indoors with more than 200 guests, only some of whom you know (which means you don’t know who is and is not vaccinated either). You don’t know much about the ventilation at the venue, but there are not open windows or doors. Wedding receptions typically involve shouting over the music and lots of dancing, so that will be high intensity activity. Let’s also assume you have to travel to get to the wedding using a flight.

What are you doing? High risk

Whom will you be with? Let’s say folks start out with the best intentions in wearing masks and distancing… but they’re having fun and possibly drinking. Eventually the masks slip down or come off altogether and distancing on the dance floor isn’t really happening: High risk

Who is in your circle? You have three kids who are not high-risk, but all adults in your regular social circle are vaccinated and none are immune-compromised: mild risk.

Where do you live or where will you be? Let’s say you live in Peoria, Illinois (high risk with 373 cases/100,000), but the wedding is in Austin (moderately high risk with 57 cases/100,000) with a layover in Detroit (high risk with 319 cases/100,000)

Your own health: Let’s say you don’t have any high-risk conditions, but you don’t have sick leave and can’t really afford to miss work for two weeks after going to the wedding: mild risk.

Here’s how that looks:

This is one where different people will make different decisions. You’re going through three airports, two of which are in cities with high levels of transmission. You’ll be at a wedding with at least 200 people who have come from different parts of the country with different infection rates, and not everyone is vaccinated. There’s a reasonably high likelihood that you’ll come into contact with multiple people who are infected, whether they’re showing symptoms or not. Your overall risk of infection is low, but it’s higher than it would be in many other situations. There is a chance, though still a pretty small one, that you could become infected. If you do, you’ll be physically fine, but you’ll have to isolate and you won’t be able to interact with anyone high risk.

A single person or a couple without kids would probably think it’s worth going since a wedding is (usually) a once-in-a-lifetime event. A family might feel comfortable taking all three kids along on the flight since the risk of hospitalization or death is extremely low for kids. But another family might not be comfortable with that risk. If a family did have a high-risk child, they might prefer to leave the kids behind with family or a babysitter, but when the parent return, will they be able to quarantine for two weeks in the unlikely, but not impossible, chance they were infected?

Let’s change one variable for who’s in your circle: You don’t have kids, and all but one adult in your regular social circle is vaccinated. None are immune-compromised, but that one adult is your 85-year-old great aunt who refuses to get vaccinated and who you visit twice a week: high risk.

If you can skip visiting the aunt for two weeks after returning, as a vaccinated person, that risk may be worth it to you. If you must visit the aunt, however, you might worry that even the small chance of becoming infected — given how high risk the situations are for transmission as a whole — makes it too risky to go, lest you pick up an infection and not realize it and pass it on to the aunt.

Example 4: Spin class

What are you doing? Indoors, with good ventilation for only one hour with high intensity activity: mild risk.

Whom will you be with? Let’s say it’s a class of 15, and you don’t know everyone (so you have to assume some are not vaccinated), but everyone is masked and distanced: mild risk.

Who is in your circle? No kids, but your partner is a organ transplant recipient who isn’t sure if they can get the vaccine yet: high risk.

Where do you live or where will you be? Let’s say Hawaii County: mild/moderate risk with 30 cases/100,000

Your own health: You have no risk factors and can afford to take off work: low risk.

Here’s how that looks:

The risk looks pretty low across the board except the one area of your circle since your unvaccinated partner is very high risk for severe outcomes. Your overall risk of infection is extremely low — even mores than any other vaccinated person given your location and the activity — but some people might feel like any risk is too much right now if they live with someone medically fragile. Others may feel more comfortable with that risk. Or, perhaps the couple talks about it and decides together that the benefits of exercise outweigh the overall small risk of an infection that you could bring home with you. Again, it’s going to depend on each person’s risk threshold.

Example 5: Take a multi-generational vacation

This is one where it can get complicated, but you can still use the tool as a guide. Let’s say you want to take a road trip to the beach and rent a massive beach house for kids, grandparents and the rest of the gang to spend a week together.

What are you doing? You’ll be spending at least some time indoors, but it’s a breezy house with good ventilation. You’ll certainly be there more than an hour, but you’re not going to be shouting in the house. Any screaming will be outside: mild risk.

Whom will you be with? It’s more than 10 people, but you know everyone and everyone is vaccinated except the kids since they can’t be (yet). You try to enforce mask-wearing in the house, but people forget and eventually think it’s not necessary since all but the kids are vaccinated: high risk (mainly because of “not following health guidelines,” but more on that in a moment)

Who is in your circle? There are kids but no unvaccinated or otherwise high-risk adults: mild risk.

Where do you live or where will you be? Let’s go with Kitty Hawk, North Carolina, where the transmission rate is moderately high with 81 cases/100,000.

Your own health: You have no underlying issues and can afford the time off if you get sick: low risk.

Here’s how that looks:

This looks good overall. The only reason for the high risk for crowd is the fact that not everyone will be wearing masks and/or distancing while inside. But then, everyone is vaccinated except the kids. If the kids weren’t present, you’d be following CDC recommendations, which say you don’t need to mask or distance if everyone is vaccinated.

Kids have extremely low risk of complications, so assuming none of the kids have big risk factors, it does feel a bit excessive to make everyone wear a mask inside just for the kids. That “high” risk isn’t really that high. (Note: The question about following health recommendations was purposely overweighted because, generally speaking, people who aren’t following health recommendations are likely to be engaging in other behaviors that are risky, suggesting they represent an overall higher risk than average. Obviously, there are exceptions.)

Now, let’s say the family wants to fly somewhere instead of drive, or they want to go to an amusement park or an arcade while on vacation. Each of these activities involves an additional risk assessment. That doesn’t mean you shouldn’t do it — chances are, with a fully vaccinated family except kids, the risk overall is low — but you have to consider whether your own kids might be a risk to others if they get infected too, a calculation not included in the NYT tool. And again, if your child does have higher risks, or you’re simply freaked out about MIS-C in kids even if the condition is rare, you should only do what you’re comfortable with.

The big picture

Most of these scenarios are ones in which many people will feel comfortable. Some people may not feel comfortable in some of them, though some of those people may be overestimating the risk.

“When we are in a fear-based mentality, when we have been traumatized like we have for the past 14 months and your body and mind are in fear mode, we tend to overestimate risk because we’re wired to protect ourselves,” Dr. McBride said. “We’ve had to run from the tiger for 14 months, so now when you think about going to a restaurant, anxiety and fear makes you overestimate that risk.”

If you’re vaccinated, though, the risk to you really is minimal. It’s primarily other people you need to think about, and that’s where the majority of the risk assessment comes into play. Overall, however, these scenarios show that it’s possible to do far more activities than we could do before vaccines were available.

“The message is clear that once you’re vaccinated, you can start to gradually resume normalcy and reclaim your health, safety and sanity,” Dr. McBride said. “The vaccines are our ticket forward. They are a triumph of modern medicine. While nothing is perfect, these are as close to perfect as you can get when perfect is not even on the menu.”

Tara Haelle is a science journalist, public speaker, and author of Vaccination Investigation and The Informed Parent. Follow her at @tarahaelle.

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