How likely are infants to be sources of COVID-19 transmission?

May 24, 2021 5:09 PM

After a painful year+ of necessary separation, my partner and I are planning cross-country flight to see partner's 1.5-year-old nibling and are trying to understand the risks posed by the fact that while we and nibling's caregivers are fully vaccinated, other people who will have close contact before our visit will not be.

It seems to be common knowledge that young children are less likely to have severe cases of COVID-19, but that risk is definitely not zero. There seems to be less certainty about how likely an infant is to transmit the infection. Is there any good information that characterizes this risk, or do we simply lack the data at this point?

During our visit, it's agreed there will be no unvaccinated* people in the home or interacting with the nibling. Since the nibling will be in contact with unvaccinated folks prior to our visit† we have two choices:

1. Accept the risk and visit directly after nibling has contact with unvaccinated adults. This timing is far more convenient for us.
2. Delay our trip for 2 weeks, during which the parents will enforce a nibling quarantine against contact with unvaccinated individuals.

Since both my partner and I are fully vaccinated (Pfizer), it does seem like the risk would be basically low. But the intent is definitely to have close contact with the nibling (no distancing/masking) so I'm not sure how that balances out. If delaying 2 weeks will substantially decrease the risk, we can accept the inconvenience, but if we go that way, I'd at least like to have a justifiable reason for doing so.

* Apart from aforementioned infant nibling
† I wish this weren't the case, but this decision is out of our hands and we're not going to try to change the parents' minds, so please don't suggest that

posted by Cogito to Health & Fitness (12 answers total)

When were the parents vaccinated? If the baby is being breastfed, it may be getting antibodies now.
posted by pinochiette at 5:14 PM on May 24, 2021 [1 favorite]

If the parents aren't willing to prevent unvaccinated people from seeing the baby, would they agree to give unvaccinated guests a rapid test? The BinaxNow OTC rapid test is available at drugstores now. If I were in your place, that would give me peace of mind that the baby is more protected and that visitors are as well.
posted by quince at 5:32 PM on May 24, 2021 [1 favorite]

Transmission to vaccinated people happens but is unusual. When it does happen, it almost always results in asymptomatic or low-symptom cases. Last I checked, there were zero reported deaths from infections of vaccinated people.

If you are willing to risk a cross-country flight, I would absolutely not worry about the risk of getting COVID from an infant as a fully vaccinated person. It might be possible, but many things in life are possible, and at some point you need to let that risk melt into the background along with all the other life risks that you never think about day to day while driving in a car, taking a shower, drinking alcohol, or walking in the rain.
posted by Winnie the Proust at 7:28 PM on May 24, 2021 [35 favorites]

I remember hearing on the Social Distance podcast (unable to find a specific episode, sorry) that infants and generally people of a smaller stature transmit the virus less, for the simple reason that their lungs are smaller and they simply cannot expel as many virus particles into the air as a larger person with larger lungs.
posted by meowzilla at 8:50 PM on May 24, 2021 [1 favorite]

First, at 1.5 years old, that child or those children are toddlers more than infants. Second, if I were taking a cross country flight (and I just took a 3 hour flight) I would not be worried in the least about catching Covid from close contact with a toddler who had been in some contact with unvaccinated people. The odds of the unvaccinated person having asymptomatic covid and then transmitting it to a toddler who would then have to get it and transmit it to you while not showing symptoms, is very very low. Further, and it is not part of your question, even if you "beat the odds" and did catch it, as fully vaccinated people, the chances you have anything other than a mild case is slim.

I would be more concerned with catching a toddler's cold than catching covid from a asymptomatic toddler.
posted by AugustWest at 9:14 PM on May 24, 2021 [12 favorites]

From what I understand, the unvaxxed nibling is much more at risk seeing you and your spouse after your plane trip than are you and your spouse, both vaxxed, at risk from the nibling.
posted by nantucket at 2:06 AM on May 25, 2021 [5 favorites]

Go at the convenient time, don't worry about toddler quarantine.

If you were bringing along an unvaccinated toddler of your own, or if you had autoimmune conditions that made you unsure of the vaccine efficacy for you specifically, the answer would be more complicated.
posted by february at 4:36 AM on May 25, 2021

Another thing to keep in mind, is that since prevalence of the virus has drooped in recent months, a group of random 10 people 3 months ago would have a 40% chance of one having the virus, now, it's more like 3%. So, it's important to take into account the dropping rates nationwide.

I'd agree with others - usually, you worry about this because you don't want to spread it. You really can't spread it much by being vaccinated. So, there's no problem visiting. The current guidance is that even if exposed you don't need to test or quarantine. So I'm unsure about any hesitation here.
posted by bbqturtle at 7:56 AM on May 25, 2021 [1 favorite]

Response by poster: Thanks for the info pinochiette, quince and meowzilla.

I know all the responses about what I should do are trying to help, but that's not what I'm asking for. My question is:
Is there any good information that characterizes this risk, or do we simply lack the data at this point?

I'm not debating whether or not to go on the cross country flight, I'm debating whether to delay a couple weeks. My way of thinking about risk may be different from yours, and that's fine. To me, taking on significantly more risk than I have during this pandemic by taking the flight makes me more sensitive to additional risks on top of it, not less.

Besides, unless we've got some data to compare, this is all conjecture, so more data, please.
posted by Cogito at 8:03 AM on May 25, 2021

I have not seen any research that is specific to transmission by toddlers and babies. When children are grouped by age, the separating line tends to be adolescence: so research might talk about children 10 and younger, versus tweens and teenagers.

There has been a lot of debate about transmission by children generally, with some studies claiming that children are less likely to transmit and others showing them more likely to transmit. I have not seen a consensus opinion emerge, and doing some googling just now didn't turn anything up. Perhaps someone else will be able to find more data for you.

Good luck with your decision and your trip!
posted by Winnie the Proust at 9:15 AM on May 25, 2021

Best answer: Is there any good information that characterizes this risk, or do we simply lack the data at this point?
Here is a summary of data on covid and children: Link


If I were you, I would punch your flight, and the hangout, into microcovid.org.

First, the flight. 70 mC.

Then, the hangout. 200mC (From the above link, Children ages 0-9: Children ages 0 to 9 make up 0.5 percent of cases in the data. For comparison, this age group is about 6 percent of the total population, so we can reduce the microcovids by 10x). So, 20mC after adjusting for childhood spread..

If you waited 2 weeks, the hangout. 2 mC, or ~0mC after adjusting for childhood spread.

Overall, these numbers are all VERY, VERY low. The difference in ~18 microcovids, or even 200 microcovids if we are pessimistic, is incredibly minimal. 200mcs is a 200 in 1,000,000 chance of getting covid, or 1/5000 chance. If you did this activity every day, it would take 6 YEARs for a 50-50 chance at covid.

And, since you are vaccinated, the covid would be much less likely to be severe, and much less likely to spread to others.

6 months ago, these numbers would have been much higher. People were debating risks in the 20,000 mC level. Today's numbers are so low, that the difference is incredibly negligible. For context, the chance of getting in a severe care accident after driving 50 miles is 37mC (though it wouldn't be microcovids, it'd be micromorts).

Another prudent example, is that the chances of you dying from being struck by lightning, on any given year, is 9mC. These are tiny numbers of odds here.

I hope this is helpful! I recommend using microcovid and narrow in on the specific region you are going. That 20 might decrease even further.
posted by bbqturtle at 9:43 AM on May 25, 2021 [8 favorites]

As a parent who has navigated the pandemic and with all the difficulty and stress that entails, I would speak on behalf of this child's parents and say: they have kept themselves and their baby safe and endured a lot of stress in the process. You and they are now vaccinated. That is cause for celebration! I can understand you all want to socialize now. But I think there's some parenting judgement wrapped in this situation and how you're considering it. It's ok to judge parents, but you should be honest that's what you're doing and not couch it as "risk" to you when it's not. It's risk to their kid.
If they feel it's safe to now let their child meet more people, I think you can either respect that and have your visit, or do not have the visit at all. If you feel it's not safe to the child (and you may be right that it's not 100% safe. I don't know the circumstances of the visit with the other people. It must be something they've worked through and decided to be ok with. So if you decide that was a dumb decision, be careful with how you phrase this and talk to them). I think it's telling that you consider the quarantine after the child sees unvaccinated people to be a burden on you, but not on them. From my point of view, that seems like a generous thing they are willing to do for you. What are you doing for them?
I think it would be best practice to change your clothes and wash your hands before visiting the child to reduce the child's exposure to any germs you may carry from the airplane. If it were my kid, I would want visitors to stay outdoors as much as possible and wear a mask when holding the child. After I felt the exposure from the plane had passed (maybe after a test? or just after some time had passed? These are the kinds of constant decisions parents are making, and the goal posts are changing daily). After I'd worked through those feelings, I would probably feel ok without the mask.
posted by areaperson at 9:49 AM on May 25, 2021 [8 favorites]