Vaccinating Our Littlest Littles

Elena Shea, MD shares a pediatrician's perspective and a break-down of the data about the newly approved COVID vaccine for our youngest children.

Vaccinating our littlest littles: The day those of us with littles under the age of 5 have been waiting for.

The FDA and CDC finally approved a safe and effective COVID vaccine for our smallest kiddos, ages 6 months through 4 years.

How excited am I?

As of this writing, my kids are already vaccinated!!!

I have been getting a lot of questions about the details and necessity of the vaccines so wanted to run through the date with everyone.



For the first time we have TWO mRNA vaccines available. With its approval for the 6 months to 5-year age group, Moderna requested, and was granted, approval for its vaccine to be used for our older kids and teenagers!

Moderna’s vaccine is an mRNA vaccine that has been available for adults since 2021. They trialed a lower dose of 25mcg (which is a fourth of the adult dose) in the 6 months to 5-year age group. Over all they had 6607 participants. It is a two-shot series spaced 4 weeks apart. About a fourth of participants had fever, more often after the second dose. Irritability, pain at the site of injection and drowsiness where the other most common side effects. There were no reports of myocarditis, though the trial was not large enough to show such a very rare event. However, we’ve seen from the data from our 5-year to 11-year-old that there has been no myocarditis.

Pfizer’s vaccine is also an mRNA vaccine and has also been available since 2020. Their vaccine is 3mcg (a third of the adult dose) and is a three-shot series. The spacing between dose 1 and 2 is 3 weeks and between 2 and 3 is 8 weeks. It had similar side effects of drowsiness and irritability, with lower incident of fever. Similar to Moderna, Pfizer had no incidents of myocarditis.



In short, YES!! The FDA required the trials to show immunobridging. This means that they required the vaccines to show that the vaccine provoked a similar antibody level as a predetermined level, in both cases similar to the levels found in 16-25 year old, where efficacy has been well established. The purpose of these studies was to determine the proper dose of this youngest age group.

Moderna’s vaccine study showed an efficacy rate between 37%-46% in 2-5 year old and 31%-51% in the 6 month to 2 year old. Moderna is also testing a third dose to complete the series and would, in theory, greatly increase the efficacy.

Pfizer’s vaccine study showed an efficacy of 80.3% after three doses. But the study showed almost NO response after two shots. This means that all three shots are needed to be protected against COVID



Yes! Yes! Yes!!

We know that overall COVID is less severe in our kids. We know that they are hospitalized less and die less than adults. But the truth is that 442 children have died from COVID since the start of the pandemic, making it the deadliest vaccine-preventable disease. And while pediatric COVID hospitalizations still remain low, compared to adults, we saw that, during the recent Omicron surge, our youngest kids did the worst. They had the highest rate of hospitalization compared to other age groups and up to 25%of hospitalized children ended up in the intensive care unit.


442 children have died from COVID since the start of the pandemic, making it the deadliest vaccine-preventable disease. Click To Tweet


We also know that our children are not immune to long haul COVID and that vaccines can prevent this up to 50%. We know that kids are uniquely at risk for MIS-C, a severe multi-organ inflammatory disease and we know, from reports, that NO kids who have been fully vaccinated and contracted COVID have had MIS-C.

Vaccines will lead to less disruption in everyday life. They reduce transmission, leading to less missed school/daycare days (and less missed work for their parents). They add another layer of protection in this population who cannot reliably mask or for whom social distancing is impossible. It is a crucial step to truly ending the pandemic.



*My child recently had COVID?

Recent infection does not guarantee immunity or long-term protection. Research has shown the post infection immune response varies between persons and is dependent on severity of disease. Our children, thankfully, tend to have mild to moderate disease but this likely means their immune response may not be robust enough to provide long term immunity. There is debate on how long post infection immunity lasts. Also, as COVID mutates, previous infections will not necessarily protect us from infection from a new variant. We have seen this recently, as many who were sick during the Delta surge were reinfected during the Omicron (and subvariant) surges.


Our children, thankfully, tend to have mild to moderate disease but this likely means their immune response may not be robust enough to provide long term immunity. There is debate on how long post infection immunity lasts. Click To Tweet


Research has shown that vaccinating post infection only INCREASE immunity. Study after study in adults show those who were previously infected AND vaccinated have a higher immune response than either infection OR vaccination alone. Within the scientific community, this is called “hybrid immunity”. The vaccine targets the virus’s spike protein while post infection immunity targets the whole virus, providing a more complete protection.


*I got my vaccine while pregnant?

That is great!! I did too, and am so happy to have been able to provide that extra immunity to my little. Antibodies flow from mothers to their babies through the placenta. We know there are ideal times to receive vaccines while pregnant (like the recommendation to get a Tdap booster during the third trimester). The issue is that this immunity wanes and is believed to be mostly gone by 6 months of age. Get your babies vaccinated! I did.


*I got my vaccines and am breast feeding?

Congratulations on breast feeding!

While antibodies are present in breast milk, they are not absorbed into the baby’s circulation. Instead, they coat the baby’s gut and protect against pathogens that enter through the intestines. Breast feeding is known to protect against GI diseases but offers less protection against respiratory diseases. So yes, being vaccinated and breast feeding can offer some protection against COVID, the truth is that vaccinating your little is best. It is a big reason that I, while I exclusively nurse, decided to vaccinate my 9mo old.

I know that choosing to vaccinate your child with a newly approved vaccine can be daunting. Know this. The vaccines being offered are lower dose versions of the vaccines being used worldwide and have been used to successfully vaccinate millions of people. We know they are safe and effective. We know COVID has caused so much upheaval in our lives and vaccinating is truly a step towards a new normal. I would never recommend this if I weren’t confident in the data. I have vaccinated all my children to keep them, and my community, safe and healthy. I hope you will to.

Be well,

Dr. Elena


(please remember to speak to your own doctor about anything you read online, as this is not intended as medical advice, nor to replace your own doctor’s care).


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