Estimating the number of US children susceptible to measles resulting from COVID-19-related vaccination coverage declines

• Type of Material: Article
• Authors: Ashley Gambrell, Emory University; Maria Sundaram, Marshfield Clinic Research Institute; Robert Bednarczyk, Emory University
• Language: English
• Date: 2022-07-15
• Publisher: ELSEVIER SCI LTD
• Publication Version: Final Published Version
• Copyright Statement: © 2022 Elsevier Ltd. All rights reserved.
• Final Published Version (URL): http://dx.doi.org/10.1016/j.vaccine.2022.06.033
• Title of Journal or Parent Work: VACCINE
• Volume: 40
• Issue: 32
• Start Page: 4574
• End Page: 4579
• Keywords: RUBELLA; HUMORAL IMMUNITY; Research & Experimental Medicine; NIS-Teen; Measles; MUMPS; MMR vaccine; COVID-19; Vaccine hesitancy; Immunology; Science & Technology; Medicine, Research & Experimental; Vaccine uptake; Life Sciences & Biomedicine; UNITED-STATES
• Research Categories: Health Sciences, Epidemiology; Health Sciences, Public Health

Abstract

Measles elimination hinges on vaccination coverage remaining above 95% to retain sufficient community protection. Recent declines in routine measles vaccinations due to the COVID-19 pandemic coupled with prior models indicating the country was close to the 92% herd immunity benchmark are a cause for concern. We evaluated population-level measles susceptibility in the US, including sensitivity analyses accounting for pandemic-related impacts on immunization. We estimated the number of children aged 0–18 currently susceptible to measles and modeled susceptibility proportions in decreased vaccination scenarios. Participants were respondents to the NIS-Teen survey between 2008 and 2017 that also had provider-verified vaccination documentation. The exposure of interest was vaccination with a measles-containing vaccine (MCV), and the age at which they were vaccinated for all doses given. Using age at vaccination, we estimated age-based probabilities of vaccination and modeled population levels of MCV immunization and immunity vs. susceptibility. Currently, 9,145,026 children (13.1%) are estimated to be susceptible to measles. With pandemic level vaccination rates, 15,165,221 children (21.7%) will be susceptible to measles if no attempt at catch-up is made, or 9,454,436 children (13.5%) if catch-up vaccinations mitigate the decline by 2–3%. Models based on increased vaccine hesitancy also show increased susceptibility at national levels, with a 10% increase in hesitancy nationally resulting in 14,925,481 children (21.37%) susceptible to measles, irrespective of pandemic vaccination levels. Current levels of measles immunity remain below herd immunity thresholds. If pandemic-era reductions in childhood immunization are not rectified, population-level immunity to measles is likely to decline further.