Children Under Age 5 Less Susceptible to COVID-19

Children are often considered virus super spreaders. But, according to Children’s Hospital of Philadelphia infectious disease expert, Paul Offit, MD, this doesn’t appear to be the case with COVID-19.

Why are young children less prone to infection with COVID-19?

We still do not know the true number of children at any given time who are infected with COVID-19, though evidence does so far suggest children under age 5 are less likely to experience severe infection.

Recent research offers a possible answer as to why: in order to enter a person’s cells, a virus must attach itself to a receptor on the surface of the cell. Because a child’s cells have less Ace2, the receptor that gets infected with the virus, COVID-19 is less capable of attaching to the cells that line their upper respiratory tract. Ace2 is maturational, meaning children under age 5 have very little of the receptor on the surface of their cells, and they develop more as they grow older.

While young children can still get COVID-19, this factor may explain why they’re generally less infectable, less contagious and less severely affected.

Do children still need to take COVID-19 precautions?

Yes. We do not yet understand why one child might become infected and not another, or why some children experience severe infection or severe complications like multisystem inflammatory syndrome in children (MIS-C). For this reason, Dr. Offit still recommends taking all necessary precautions to keep your children safe, including mask use, excellent hand hygiene, physical distancing from those not in your household, and avoiding crowded, poorly ventilated spaces.

Notes of hope

Offit says he is hopeful that we are on the verge of getting on top of the virus. Here’s why:

1. We have two vaccines in hand right now. Many of CHOP caregivers have already been vaccinated so they can continue to safely care for your child and family.
2. The vaccines are safe and more than 90% effective.
3. We are getting better and better at distributing the vaccines on a mass level.
4. The incoming administration is prioritizing vaccination, with a goal of reaching 100 million vaccinations in its first 100 days.
5. Two more vaccines are on the way.
6. We are heading into warmer weather. Humid weather makes it harder for the virus to spread.
7. At least 20% of the population is already immune.

Offit clarifies this final point by noting that while it’s reported that an estimated 22 million people have been infected with COVID-19, that number only accounts for people who have been tested. He estimates that if we looked instead at antibody studies — which are a much more effective way of measuring who actually has been infected — closer to 60 million people in the country have likely already been infected.

“That's 20% of the population,” he says. “Those people are already probably, at a large level, protected against the severe nature of this virus. When they're re-exposed to the virus, they are going to be very unlikely to be hospitalized or die.”

Offit stresses that it’s still important to get the vaccine even if you did have COVID-19 previously, and that the vaccine is much safer than being exposed to the virus. And once vaccinated, you should still avoid traveling and gathering in groups until transmission of the virus decreases, which he predicts will happen in the spring.

There is still much we are learning about the virus and the vaccines, as well as the role of children in spreading and catching it. We have created a COVID-19 vaccine section on our website, which is updated regularly with the most current information to keep you and your family informed.