pb&j questions

Your COVID Vaccine PB&J Questions Answered!

The PB&J Method breaks down the CDC guidelines on mixing vaccinated & unvaccinated people. You wrote in with questions—here are the answers!

by Steve Silvestro, MD  @zendocsteve

You can also listen to this article as a podcast on your favorite podcast app or click on the player below:


Woohoo! As I write this, roughly 40% of the U.S. population have received at least one dose of a COVID-19 vaccine, and 25% have been fully vaccinated. Those numbers are still lower than we need to start ending this thing, but we’re getting there!

As many of you know, a few weeks ago I wrote about the updated CDC guidelines for how vaccinated and unvaccinated people can mix indoors and unmasked, and I created an analogy to help us all remember these rules more easily—The Peanut Butter & Jelly Method (You can read about it here).

In a nutshell, the PB&J Method says:

  • All fully vaccinated people are peanut butter, all unvaccinated or partially vaccinated people are jelly
  • Each household has its own flavor of jellies
  • Peanut butters (vaccinated people) can mix together unmasked and indoors, and can mix with one flavor of jelly
  • Different flavors of jellies can’t mix (that’s just gross)
  • No one can mix mask-free if a jelly is at high risk for severe COVID due to health issues

I was floored by the wonderful response the article received! I was also honored that so many people emailed or messaged me on Instagram with questions about their own families’ situations—and while I tried to write back to everyone, I admit that I was a little overwhelmed by the number of messages and questions I received.

Luckily, many of those questions shared a few common themes—some of which may match your own family’s situation or are similar to questions you’ve had yourself.

So I’ve selected a handful of the questions I received and I’m sharing them and my responses below. Between these scenarios and the examples I provided in the original article, I hope you can feel more confident in making COVID-related decisions for your family.


Hi Dr. Silvestro,


Thank you for this article. Are you saying that vaccinated people are not carriers? If you are, can you please provide citations? When our parents visit with other vaccinated people or a sibling’s family (not vaccinated), we have been advised (as we are not vaccinated) to ask our parents to then isolate for two weeks or 7 days and a Covid test before they see us. We haven’t read or spoken to anyone who says vaccinated people are not carriers. Yours would be the first place we’ve heard that it is ok as long as not all together unmasked at the same time. 



And a similar question:

Hi Dr. Silvestro, 


The PB & J Method is genius, thank you for that. But what is the data, really, about the ability of “Peanut Butters” to asymptomatically transmit to “Jellies”? This is where my husband and I are not sure what to do, as it doesn’t seem like there’s much we can read about it. The standard line is to say, “Stay masked and distanced until all are vaccinated”. We wonder how long that will take. My sister is fully vaccinated and has barely seen our boys for a year. Would you say (based on data) that it’s now “safe” to have her unmasked in our house with me and my boys (all the same Jelly) and my husband (a vaccinated PB)?


Again, thank you so much for taking the time to break this down for us normal folk, and to put it out there as a trusted individual. It means a LOT.


This was perhaps the most common thread in all of the questions I received: Can vaccinated people pick up the virus, never develop symptoms, and then pass it on asymptomatically to unvaccinated people?

Asymptomatic transmission is a big deal—it’s estimated that over half of all infections are caused by asymptomatic carriers. So it’s right to wonder how effective the vaccines are at preventing asymptomatic infections—you don’t want to think all is fine and dandy after getting vaccinated, then unwittingly pick the virus up and pass it on to your kids or others.

And while the honest answer is yes, vaccinated people can potentially become asymptomatic carriers, as the vaccine isn’t 100% effective, the more complete answer is that the chances of that happening seem to be extremely slim—so slim that it can be considered safe for peanut butters to hang out with one flavor of jelly (one unvaccinated household) without masks worry-free.


The data we currently have shows that fully vaccinated people have a very low chance of either 1). Catching the COVID-19 virus at all, or 2). Spreading it to others if they do.

Data from Israel shows that the Pfizer vaccine is 94% effective at preventing asymptomatic infections. Even a single dose of the Pfizer vaccine (which, remember, requires two doses for full immunity) has been shown to be 74% effective against asymptomatic infection. Johnson & Johnson’s trials showed 74% efficacy against asymptomatic infection with their one-dose vaccine, and early data from the Moderna trials showed benefit, as well.

Real-life numbers are looking even better. The CDC recently reported that out of 77 million people who are fully vaccinated, there have been 5,800 breakthrough infections—a rate of just 0.008%. Studies of healthcare workers, who theoretically have a higher likelihood of catching COVID because of greater exposure, have a slightly higher but still impressively low risk. Data from UCSD and UCLA show a breakthrough infection rate of just 0.05%, as does data from University of Texas Southwest Medical Center—just 13 out of 23,111 fully vaccinated people between the two studies.

On top of that, there is now also research showing that the vaccine may decrease replication of the virus in the airway (nose, mouth, lungs, etc.). Fully vaccinated people who do catch the virus only produce a quarter of the amount of virus in their airway that an infected, unvaccinated person would. And since we know that the most important way the virus is spread is via droplets and aerosols, if a vaccinated person does actually catch the virus—whether with or without symptoms—the fact that they produce less of the virus in their airway means they should be far less effective at spreading it to an unvaccinated person.

Now remember—in order to catch it and spread it, you need a solid exposure to the virus first. That’s why the CDC continues to recommend that fully vaccinated people wear masks and keep distance when in public (essentially, when they’re around multiple flavors of jelly). Continuing with this basic precaution in public decreases the odds of you having a significant exposure in the first place.

All of this taken together means that the risk of a fully vaccinated person contracting an asymptomatic COVID infection and then spreading it to unvaccinated people is very, very low.


Hi, Dr. Silvestro!

I wanted your opinion on the safety of vaccinated parents doing more out-of-the-house activities, while still protecting their kids, like going to the nail salon, browsing the mall, etc. These are things my friends and I have avoided for the most part. Now that many of us are becoming fully vaccinated, I’m wondering if these previously risky activities are still risky to our children even though we have been vaccinated.

Thanks so much!


This was also a common thread among the questions I received. After a year of living with all of the anxiety that comes with a global pandemic, it’s going to take time for some of us to get comfortable doing many of the normal things we used to do (while other people seem to have no problem jumping right back in!).

Of course, nothing is perfect. Even a 95% effective vaccine—essentially like the Pfizer and Moderna vaccines according to the original data—will be ineffective 5% of the time. But at some point, we’ve got to trust that the vaccine is doing its job. For some, that might mean waiting until community numbers are lower; for others, it might be right now.

This is another reason why the new CDC guidelines still recommend that fully vaccinated people continue to wear masks and practice smart distancing when in public (i.e., when they’re with multiple flavors of jelly).

Continued safety measures by fully vaccinated people are really important now while we’re building up the number of people who are fully vaccinated. At some point, we’ll ideally have enough people with immunity that fully vaccinated or otherwise-immune people won’t have to worry about masking or figuring out who’s a peanut butter and who’s the right flavor of jelly.

To quote the CDC: “In one study, complete relaxation of prevention measures prior to adequate vaccination coverage resulted in essentially no reductions in SARS-CoV-2 infections [meaning that the virus continued to spread in the community if people stopped wearing masks before enough people were vaccinated]. However, preliminary data suggest that increasing vaccination rates may allow for the phasing out of some prevention measures as coverage increases.”

For now, the guidance for fully vaccinated people going out and doing things in public is still the same—you’ll need to wear a mask and try and keep some distance from strangers. But hopefully you can marry this with the comfort of knowing that your own, personal risk of doing normal things in public after being fully vaccinated is still really low.

I can tell you that personally, having received both doses by early February, I’ve felt comfortable going into stores, getting a haircut, etc., and I’m of course wearing a mask when I do. That said, I’ll still wash my hands or use sanitizer if I touch a lot of things in a store, and I try and schedule things like haircuts early in the morning so that there have been fewer total people in the small space.

My suggestion is that a fully vaccinated person continue to be smart and kind by taking precautions in public, but that they can hopefully do so with far less anxiety they may have felt before.


Dr. Silvestro,


We are divorced, so my daughter goes back and forth between her father’s home and mine. I am guessing this automatically means she herself is considered 2 households? Does that make me automatically 2 households? How does that impact what her vaccinated grandmother has to do if she comes to babysit?

Many people wrote in with what I’d call “grey area” scenarios—situations that aren’t specifically spelled out by the CDC guidelines, but that instead require a bit of inference.

This is a really tricky one—and one that I’m sure many, many families have had to try and figure out.

When it comes to figuring out whether divorced parents’ separate homes count as two households for the CDC guidelines—meaning that people in each home are a different flavor of jelly—I would say that it depends on two big factors:

  1. Are there other unvaccinated people in one home that don’t live in the other—additional adults, step-siblings, grandparents, etc.? If so, then I would consider these two separate households. If the only people in each household are the divorced parents and any siblings who also go between homes, then we can likely be safe enough to count them as a single flavor of jelly.
  1. Are the COVID-related behaviors in one home similar to those in the other? If both homes have similar practices when it comes to mask-wearing, avoiding crowds, etc., then I would suggest you can consider them “one household.” But if practices in one home are very different from the other—if one home has people who aren’t great about wearing masks in public, who eat indoors at restaurants/bars, etc.—then I’d feel obliged to count the homes as separate households.

Of course, even if we count both homes as separate households when it comes to the PB&J guidelines, that doesn’t mean the parents and kids need to wear masks 24/7 in the home—that’s unreasonable.

But when it comes to a vaccinated grandmother coming to visit—that’s tough. If we’re truly to consider the homes two separate households and that the kids are part of both, it may be best for everyone (or at least the babysitting grandparent) to wear a mask when indoors. Perhaps one way around that is if the kids have been in one home for the last 14 days—kind of like they’ve “quarantined” in a sense—but I know that that’s not a common scenario when parents share custody.

This isn’t an easy call and I admit that any answer to this scenario will be a little murky.


Hi Dr. Silvestro!


I was curious how the PB&J could be applied to cross country travel.  My in-laws live in a distant state and are vaccinated.  They have not seen my 4 kiddos in a few years because of surgery then the pandemic. I am almost fully vaccinated, hoping my husband will be by their time of travel.  So, if they drive across country, and probably have to stay in a few hotels.. what does that mean for our kids? no different kinds of jelly, but, in event that when vaccinated they could pass on to the kids, is that a concern?  I was thinking it would most likely be fine.. maybe stay outside?  or just no hugs? 


Also, please let your wife know that we think she is the bees knees. Love love love her 10-minute Preschool videos!

There are a few considerations we can tease out here to get a good answer. First, we’ve stated that there’s pretty low risk of a fully vaccinated person contracting the COVID-19 virus, and lower risk of them spreading it even if they do. That’s good.

Second, we can turn to the updated CDC guidance, which states that fully vaccinated people can travel within the United States without having to worry about testing or quarantining on either end of their trip. Built into this recommendation is the recognition that those traveling grandparents have low risk of picking up the virus once they’re fully vaccinated. But also baked in there is that recommendation that fully vaccinated people continue to wear masks and practice distancing when they’re in public.

So if those traveling grandparents use precautions at rest stops and in hotels—wearing masks, avoiding eating in the lobby or continental breakfast area—then they should be all-clear to travel and visit the grandkids mask-free.


Dr. Steve,
We read and listened to your peanut butter and jelly rules of thumb. We are grandparents with 3 adult children (and spouses) and 6 grandchildren. All 8 adults will be fully vaccinated—peanut butter. Four of the 6 grandchildren are under 4 years old. The other 2 grandchildren are ages 10 and 12. As for family get-togethers and an upcoming summer vacation, I realize that the four grandchildren under 4 are different flavored jellies, but doesn’t it matter that their risk of their contagion appears extremely low? 

With schools opening and being told about the lowest risks for the youngest children, we are not sure that the rationale for separation of jellies, other than a zero risk mentality, supplants the other cautious efforts being made and the overall much lower risk. Shouldn’t your advice reflect the age of the jellies and the overall precautions being taken by the jelly families? Or is the best advice to quarantine the jellies for 7 days before we vacation together and have them tested (and then proceed without masks and distance). We are cautious people, but wonder when enough is enough.

I can empathize with the feeling of wondering “when enough is enough.” Since we collectively blew our shot at squashing the pandemic a year ago, and with so many people living life like there isn’t a pandemic at all, it can be really hard to find the balance between being 100% “pandemic perfect” and bending the most bendable rules.

As a pediatrician, I can tell you this year has been even more frustrating when it comes to getting a clear answer on COVID and kids. We go back and forth between thinking they’re major spreaders or not; most kids seem to get mild or no symptoms when they do contract it, while others end up hospitalized or with evidence of inflammation of the heart; they get more virus in their noses, but we’re not totally sure what that means; and the closing of schools and activities last year muddied our picture of what kids’ risks for catching and spreading COVID-19 really are.

Ultimately, though, we know for sure that kids aren’t “immune,” even if they’re quite young and may be less likely to have severe disease. And when it comes to teasing out a child’s risk level based on their family’s activities, the challenge is that what one family considers—and then tells other people—to be “low risk” may not always be the case. I know of plenty of families who over the past year thought their kids were isolating because they were in “pods”—but they were distance learning with one pod of friends, had another “pod” for their tennis class, and had siblings who each had their own sets of multiple pods. The result is that a family with three kids has 9 “pods” just for the kids. You can see where I’m going here… What one family considers “safe practice” may not always be what you consider—or what actually is—safe.

What’s more, should any of the kids gathering for a family vacation happen to have a medical condition that puts them at higher risk for severe COVID—asthma, overweight, and diabetes might be the ones a family would be most likely to encounter—then sticking to the rules is even more important.

When it comes to mixing different jellies for an extended period of time like a big family vacation, it really is best to have all the jellies quarantine for 7 days and then get tested (and continue to quarantine while waiting for results) or quarantine for 14 days before the gathering, no matter how old the jellies are. It’s a bit of a hassle, but the payoff if worth it.


It’s clear that even with a clever analogy to simplify the CDC recommendations, there are still fine details and unique situations that make real-life situations less clear-cut!

However, I hope that between the examples above and those covered in the original article, you can find a solution to just about every peanut butter & jelly scenario your family might encounter.

In the meantime—be well & have fun,

Dr. Steve

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