Pediatric State of Affairs: April 28

There are several new developments that have come to the surface in the past few weeks for children. Here is an update for us parents out there.

Epidemiology

Omicron was a record-breaking wave, especially for children. At its peak, more than 1.15 million children were infected per week. The CDC reported that infection-induced immunity increased from 44 →75% among 0–11 year olds and 46→74% among 12–17 year olds from December 2021 to February 2022. This was a drastic increase, even compared to other age groups.

Seroprevalence of infection-induced SARS-CoV-2 antibodies,* by age group — United States, September 2021–February 2022. Published in MMWR here.

This wave did not come without suffering. More than 11,000 children were hospitalized in 25 states, and five times as many children ages 4 and younger were hospitalized compared to previous waves. Of the 5-11 year olds hospitalized during Omicron wave, 90% were unvaccinated, 30% did not have an underlying condition, and 20% required ICU admission. The disease profile also slightly shifted with Omicron. A JAMA study found Omicron was associated with a 3-fold increase in hospitalized Upper Airway Infections (like croup) compared to prior variants. During the Omicron wave, Kaiser Family Foundation reported COVID19 was the fourth leading cause of death for 5-24 year olds.

Importance of vaccination

High rates of infection will, no doubt, help build an individual- and population-level immunity wall. This is especially true if your child was vaccinated. We’ve had 30+ studies showing that “hybrid immunity” is superior compared to either vaccine or infection alone. This is not a reason to go purposefully get your child infected, but it is a strong viable path to protection.

Unfortunately, only 35% of 5-11 year olds and 68% of 12-17 year olds have one dose of the vaccine. That also means a whole lot of parents are relying on infection-induced immunity for their children’s protection. There are three big reasons why I wouldn’t rely on this protection in the face of Omicron:

1. Neutralizing antibodies, our first line of defense, don’t stick around for long. Before Omicron, the rule of thumb was 90 days but this has probably shortened due to Omicron continuing to mutate to escape immunity. The most recent sister lineage, BA.2.12.1, is rapidly gaining speed in the U.S. and its two new mutations further escape immunity. BA.4/BA.5 (which are circulating in South Africa) have the same mutation, too. We are confident that Omicron will continue to mutate to chip away at immunity.

2. Perhaps more importantly, we’re seeing Omicron-induced immunity among unvaccinated people does not protect against other variants of concern, like Delta (here, here, here). In the New England Journal of Medicine article, those with an Omicron infection had incredibly low cross-reactivity (i.e., in the Figure, the circles are lower in Panel B compared to the other panels). In other words, an Omicron infection didn’t provide broad protection against future infections from other known variants. While Omicron may be the only variant circulating right now, that certainly can change in the future. And if, for example, another Delta variant came along that is far more severe, these kids may be out of luck.

3. Your child’s Omicron infection may have induced B-cell and T-cell defenses too, which help protect against future severe disease and death. However, this is not guaranteed, especially with Omicron. The quality of response (i.e. memory B-cells and T-cells) is relative to the severity of infection. If a child had a mild infection (which many do), then they likely had a lower viral dose, and that secondary protection is less likely.

We want our kids to have the broadest, strongest immunity wall they can have. And this can be achieved through vaccination.

Under 5’s Vaccine

This evidence also highlights the importance of getting kids under 5 vaccinated. The most recent vaccine timeline has been largely comprised of whispers on the street, but this is what I’ve gathered:

• Moderna: On March 24, Moderna announced that their pediatric vaccines worked. The efficacy wasn’t ideal (48%), but expected with Omicron’s ability to escape immunity. Today they officially applied for an EUA after a few weeks of addressing incomplete paperwork. It typically takes the FDA 5-6 weeks to review everything (It took them 5 weeks to review Pfizer’s 5-11 vaccine), but maybe they will take this opportunity to step on the gas! If they don’t, this would land us in mid-June for the VRBPAC meeting.

• Pfizer: Concurrently, we’re waiting for third-dose Pfizer data. I would assume Pfizer is working in overdrive to get their data analyzed and submitted. I’m a little surprised we haven’t heard anything yet, which is making me a little nervous about the effectiveness of their third dose. Nonetheless, if and when Pfizer turns their data over, the FDA will review it. Because the FDA already has their two-dose data, I would assume this would be faster than Moderna.

So, it’s possible that both vaccines would be reviewed at the same VRBPAC meeting in June. If Pfizer doesn’t submit their data in time, it’s 100% reasonable (and should be 100% expected) that the FDA would go forward without Pfizer. I’m optimistic we will have a vaccine by June.

Treatment

While we anxiously wait for a vaccine, we finally got the first COVID19 treatment for children under 12. On Monday, the FDA expanded the approval of Remdesivir (official name is Veklury) for children 28 days and older and weighing at least 7 pounds. This drug slows down viral replication in our cells, which allows the immune system to fight the virus more effectively and quickly. A clinical study of 53 hospitalized children received Veklury for up to 10 days, and it was shown to be safe and effective. Remdesivir is approved only for children hospitalized with COVID19.

Bottom Line

With an Omicron sweep, it’s still incredibly important to get kids vaccinated. Thankfully, this is coming for us parents with kids under 5. In the meantime, we have other tools that work, like treatments, boosters, antigen tests, and masks. For some reason, a vaccine seems like the finish line of this exhausting two-year road as a parent. And I couldn’t be more excited that it’s finally on the horizon.

Love, YLE

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“Your Local Epidemiologist (YLE)” is written by Dr. Katelyn Jetelina, MPH PhD—an epidemiologist, biostatistician, professor, researcher, wife, and mom of two little girls. During the day she has a research lab and teaches graduate-level courses, but at night she writes this newsletter. Her main goal is to “translate” the ever-evolving public health science so that people will be well equipped to make evidence-based decisions. This newsletter is free thanks to the generous support of fellow YLE community members. To support the effort, please subscribe here: