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How a COVID Booster Campaign Could Keep Kids Out of the Hospital and in School

A health worker prepares to administer a dose of Pfizer covid-19 vaccine to a girl at the Sanford Civic Center.

A health worker prepares to administer a dose of the Pfizer-BioNTech COVID-19 vaccine to a girl in Sanford, Fla., on Dec. 1, 2021. A widespread booster campaign for school-age children 5 and older would substantially reduce pediatric hospitalization and support school attendance. Photo: Paul Hennessy/SOPA Images/LightRocket via Getty Images

A health worker prepares to administer a dose of the Pfizer-BioNTech COVID-19 vaccine to a girl in Sanford, Fla., on Dec. 1, 2021. A widespread booster campaign for school-age children 5 and older would substantially reduce pediatric hospitalization and support school attendance. Photo: Paul Hennessy/SOPA Images/LightRocket via Getty Images

Authors
  • meagan fitzpatrick headshot
    Meagan C. Fitzpatrick

    Faculty, Center for Vaccine Development and Global Health, University of Maryland

  • Seyed M. Moghadas
    Seyed M. Moghadas

    Professor of Applied Mathematics and Computational Epidemiology, York University

  • Arnav Shah
    Arnav Shah

    Senior Research Associate, Policy and Research, The Commonwealth Fund

  • Headshot of Thomas Vilches
    Thomas Vilches

    Postdoctoral Researcher, York University

  • Abhishek Pandey, PhD
    Abhishek Pandey

    Research Scientist in Epidemiology (Microbial Diseases), Yale School of Public Health

  • Alison Galvani, Ph.D
    Alison Galvani

    Founding Director, Yale Center for Infectious Disease Modeling and Analysis (CIDMA); Burnett and Stender Families Professor of Epidemiology, Yale School of Public Health

Authors
  • meagan fitzpatrick headshot
    Meagan C. Fitzpatrick

    Faculty, Center for Vaccine Development and Global Health, University of Maryland

  • Seyed M. Moghadas
    Seyed M. Moghadas

    Professor of Applied Mathematics and Computational Epidemiology, York University

  • Arnav Shah
    Arnav Shah

    Senior Research Associate, Policy and Research, The Commonwealth Fund

  • Headshot of Thomas Vilches
    Thomas Vilches

    Postdoctoral Researcher, York University

  • Abhishek Pandey, PhD
    Abhishek Pandey

    Research Scientist in Epidemiology (Microbial Diseases), Yale School of Public Health

  • Alison Galvani, Ph.D
    Alison Galvani

    Founding Director, Yale Center for Infectious Disease Modeling and Analysis (CIDMA); Burnett and Stender Families Professor of Epidemiology, Yale School of Public Health

Toplines
  • The COVID-19 pandemic has had major consequences for children’s health, education, and well-being, including more than 163,000 hospitalizations and 1,800 deaths among those age 17 and under

  • A new study finds that a booster vaccination campaign that reaches 80 percent of eligible individuals of all ages could prevent up to 51,000 pediatric hospitalizations and 29 million days of school absenteeism

The COVID-19 pandemic has disrupted normal life, with notable consequences for children. As of October 30, 2022, COVID-19 has caused more than 163,000 hospitalizations and 1,800 deaths in children up to age 17. In addition, school closures — used to stop the spread of the virus globally in 2020 — affected more than 90 percent of the world’s students. Since then, students have faced instability in their personal lives, outbreak-driven school closures, and transition to and from virtual or hybrid learning formats. The repercussions are evident, with children achieving lower test scores compared to those students received before the pandemic.

The Centers for Disease Control and Prevention (CDC) has expanded eligibility for the bivalent booster, which targets the highly transmissible Omicron variants, to include all school-aged children 5 and older. Our previous research has demonstrated that successful fall vaccination campaigns could prevent a surge of COVID-19, markedly reducing severe disease and deaths across all ages. These effects can be attributed to direct protection among vaccinated individuals and indirect protection via a reduction in transmission for the population overall, including children under age 5 who are not currently eligible for updated boosters.

In this analysis, we highlight the benefits to children of an improved and widespread booster vaccination campaign. We expand our previous analysis to include the impact on pediatric hospitalizations, pediatric isolation days, and school absenteeism (among children ages 5 to 17), demonstrating both the health benefits of vaccination and the importance of vaccination uptake for maintaining uninterrupted in-school education. While previous analyses have estimated the number of potential deaths averted under different vaccination scenarios, the number of pediatric deaths resulting from COVID-19 infection is very low (less than 1% of all COVID-19 deaths in the U.S. since the start of the pandemic), so we chose to exclude death as an outcome variable in this analysis. We conducted this analysis using a previously developed simulation model to estimate the impact of vaccination rates under different scenarios. (See “How We Conducted This Study” for further details.)

Guidance from the CDC stipulates that individuals who test positive for COVID-19 should isolate for at least five days. A 10-day isolation period is advised for people with continuing symptoms or those experiencing shortness of breath, low oxygen levels, or hospitalization. In our model, we calculated pediatric isolation days as five days per event for children who experience mild symptomatic illness, and 10 days for those with hospitalization or severe illness.

As in previous analyses, we projected outcomes under a range of booster coverage scenarios. These include: a baseline strategy with daily vaccination rates matching those in August 2022; a campaign scenario with booster vaccination rates matching influenza vaccine rates in 2020–21 by the end of 2022; and a campaign scenario with 80 percent of eligible individuals age 5 and older receiving a bivalent booster dose by the end of 2022. We then determined the estimated impact by comparing the projected number of pediatric isolation days, days of school absenteeism, and pediatric hospitalizations from October 1 to March 31.

Fitzpatrick_covid_booster_campaign_kids_Exhibit_01

We estimated that a booster campaign that achieved age-specific coverage similar to the 2020–21 influenza vaccination levels (Scenario 1) would avert more than 36 million pediatric isolation days and more than 22 million days of school absenteeism. A more ambitious booster campaign reaching 80 percent of eligible individuals of all ages (Scenario 2) would avert more than 46 million pediatric isolation days and almost 29 million days of school absenteeism.

Fitzpatrick_covid_booster_campaign_kids_Exhibit_02

In addition, we projected that more than 38,000 hospitalizations among children could be averted, of which nearly 9,000 would be expected to require intensive care, by a booster campaign achieving influenza-like coverage. If 80 percent of eligible individuals receive boosters, almost 51,000 hospitalizations would be averted, of which more than 11,000 would be expected to require intensive care.

Increased Booster Uptake Benefits More Than Health

A booster campaign achieving high rates across age groups would substantially reduce pediatric illness and hospitalization and support school attendance. School absenteeism is disruptive to students, families, and society overall. For families, school absenteeism can impose productivity losses and economic burden, with adult caregivers needing to stay home from work. Vaccination can help maintain in-person learning and prevent infection from spreading through the classroom.

An Effective Booster Campaign Can Reduce Strain on Pediatric Hospitals This Winter

Our projections highlight the impact of booster campaigns on pediatric hospitalizations. This element is particularly salient for the fall and winter of 2022 given the early onset of both respiratory syncytial virus (RSV) and influenza, which is already straining pediatric hospital capacity nationwide. A concurrent surge in pediatric COVID-19 hospitalizations could be prevented by an accelerated booster campaign.

Throughout the pandemic, children have experienced direct health burdens as well as enormous upheaval in their personal and educational lives. Accelerated vaccination campaigns that achieve high coverage across all ages have the potential to prevent a possible imminent surge in COVID-19, protecting children both directly and indirectly and providing them with additional stability in terms of school attendance and other social engagement. The cost of inaction could be steep: millions more days of school absenteeism and thousands of preventable hospitalizations for children.

How We Conducted This Study

We previously projected COVID-19 health and economic outcomes under a range of bivalent booster coverage scenarios. These scenarios include a baseline strategy with daily vaccination rates matching those from August 2022; a campaign scenario with bivalent vaccine coverage achieving the age-specific influenza vaccine coverage in 2020–21 by the end of 2022; and a campaign scenario with 80 percent of eligible individuals age 5 and older receiving a bivalent booster dose by the end of 2022. Here, we focused specifically on the pediatric outcomes and expanded our assessment of booster campaign impact to include pediatric isolation days and school absenteeism.

We generated projections using an age-stratified, agent-based model of COVID-19 that accounts for the waning of naturally acquired or vaccine-elicited immunity. The model, updated with most recent estimates of vaccine effectiveness and SARS-CoV-2 variants, was calibrated by fitting to the reported variant-specific incidence of COVID-19 between October 2020 and August 31, 2022. The fitted model was then validated using the trends of hospitalization and deaths during the same period. We simulated our model forward from September 1, 2022, to March 31, 2023, under a baseline and counterfactual scenarios of booster vaccination campaigns. In the baseline scenario, the daily rate of vaccination was set to the average daily number of 28 vaccine doses per 100,000 population administered during August 2022 and continued until March 31, 2023. In counterfactual scenarios, this average rate was maintained through September 30, 2022, before initiation of accelerated fall vaccination campaigns.

Accelerated vaccination campaigns were simulated between October 1 and December 31, 2022. We considered two campaign scenarios that differed in the coverage achieved. In the first scenario we implemented age-specific rates of vaccination, such that age-specific booster coverage among the eligible population would be the same as vaccination coverage achieved for the 2020–21 influenza season. Under a second, more ambitious, scenario we considered an 80 percent booster coverage of eligible individuals age 5 and older. Following the operational guidelines (as of August 20, 2022) of the Centers for Disease Control and Prevention (CDC), we considered those age 5 and older to be eligible if they had received the last dose of their primary series or booster dose at least four months prior.

Although the bivalent vaccines have been shown to generate significantly higher levels of neutralizing antibodies against the Omicron subvariants, real-world estimates of their effectiveness are currently lacking. In our analysis, we conservatively set the effectiveness of the bivalent vaccines against infection, symptomatic infection, and severe disease caused by the BA.4 and BA.5 subvariants to those observed for a booster dose of the monovalent vaccines countering the BA.1 subvariant.

To account for the fact that school is typically only five days per week, when calculating days of school absenteeism, we multiplied pediatric isolation days among children ages 5–17 years by 5/7. We further reduced the total days of absenteeism by 3.23 percent, to account for the percentage of children who are homeschooled. We then calculated the number of school days missed per 100 nonhomeschooled children across the six-month analytical period, based on a total population of 54,739,095 children ages 5–17.

Note on Estimates

Our analysis is conservative in a number of aspects. Specifically, we have assumed that school absenteeism only applies to symptomatic children. CDC guidance states that all students who test positive should be isolated for at least five days, irrespective of symptoms. Although testing of close contacts is far from universal, many people still test when they have a known infectious contact. This practice will identify a proportion of asymptomatic and presymptomatic cases in children, which will lead to additional absenteeism of those students. Our analysis also conservatively assumed that children will only be absent for the minimum of five days when mildly symptomatic and 10 days when severely symptomatic. However, if children remain ill beyond these minimum durations, CDC guidance stipulates that they should not return to school until symptoms resolve.

In addition, our results are subject to the following considerations:

First, SARS-CoV-2 mutates rapidly, with immune-evasive variants continuously challenging control. Since we did not consider the rise of yet another immune-evasive variant in our analysis, the estimated magnitude of the surge is primarily driven by waning immunity. With the rise of new Omicron subvariants, or an entirely new variant, the surge could be significantly larger, and our results may therefore underestimate the benefits of bivalent booster vaccination in terms of isolation days, hospitalizations, and school absenteeism.

Second, the CDC has recently updated guidance regarding isolation of individuals with COVID-19 and quarantine of those who have been exposed. However, as we do not yet have concrete data regarding adherence to previous guidance or behavioral changes in the wake of the update, we did not include this element in our projections. These relaxed measures are likely to fuel a more substantial fall surge than predicted here, as many people remain infectious beyond the fifth day following symptom onset, and their increased circulation in the community contributes to onward transmission.

Third, we did not incorporate holiday-driven contact into our simulations. Many people celebrated fall and winter holidays modestly in 2020 and 2021, but this may not hold true for 2022, which could similarly drive a higher, earlier peak in COVID-19 cases than projected by our model.

Publication Details

Date

Contact

Alison Galvani, Founding Director, Yale Center for Infectious Disease Modeling and Analysis (CIDMA); Burnett and Stender Families Professor of Epidemiology, Yale School of Public Health

Citation

Meagan C. Fitzpatrick et al., “How a COVID Booster Campaign Could Keep Kids Out of the Hospital and in School,” To the Point (blog), Nov. 15, 2022. https://doi.org/10.26099/5a30-dw39