The COVID-19 pandemic has diverted parents' attention away from other potentially severe infectious diseases, and vaccine hesitancy has risen, resulting in delayed childhood vaccinations for measles—especially in low- and middle-income countries (LMICs) but also in the United States, two new studies have found.
Proven vaccine, preventable deaths
The first study, published yesterday in Nature by a team led by researchers from the Institute for Health Metrics and Evaluation (IHME) at the University of Washington, assessed measles vaccinations in 101 LMICs through 2019. They found that, while substantial progress was made in immunizing children against measles from 2000 to 2010, efforts stalled in the last decade in LMICs.
The lowest community-level measles vaccination rates in 2000 were in Ethiopia and Nigeria but had shifted to Afghanistan by 2019. Most children who were unvaccinated in 2019 lived in cities.
Even before the coronavirus pandemic, few LMICs had achieved the global goal of 80% vaccination coverage in every community and district, the authors noted. In 2017, nearly 18 million children had measles, with more than 83,000 dying from the disease.
Coauthor Heidi Larson, PhD, MA, of the London School of Hygiene & Tropical Medicine, said in an IHME news release that the local-level mapping used in the study is important because national vaccination rates alone mask geographic differences.
For example, India, Chad, and Ethiopia all showed increasing measles vaccination rates, but India's vaccination inequalities by region decreased, while those in Chad and Ethiopia rose. "These inequities can expose pockets of vaccine hesitancy as well as access issues," she said. "Hesitancy in the context of COVID fears or anxieties around a new COVID vaccine should not inhibit any parent from ensuring their children are vaccinated against measles."
The researchers said it was "unconscionable" that so many children are dying of measles, a preventable disease for which a vaccine, which was formulated in the 1960s, has been universally recommended since 1974. "Health leaders need to recognize the magnitude of this problem," coauthor Jonathan Mosser, MD, MPH, of the IHME, said in the release. "We need new strategies to identify communities that are falling behind and enable them to reach all unimmunized children with this safe and effective vaccine."
Lead author Alyssa Sbarra of the IHME, said that it will be critical to address both pre-existing measles vaccination gaps and those delayed due to the pandemic. "If that doesn't happen, the pandemic will compound the existing weaknesses in immunization systems and put more children at risk for measles."
Fewer pediatric wellness checks
In the second study, published today in Pediatrics, researchers measured changes in measles vaccination rates by age 16 months from March 2017 to August 2020 in the Nationwide Children's Hospital pediatric primary care network in Ohio, which provides care for more than 90,000 children and teens, most of them racial minorities and Medicaid beneficiaries.
From March 2017 to March 2020, 72.0%, on average, of 16-month-old children had received the measles, mumps, and rubella (MMR) vaccine. But that proportion fell to 66.8% in April and May 2020 and then to 62.4% from June to August. While the drop began in March, when Ohio instituted pandemic stay-at-home orders, but it persisted through August, when clinics began offering in-person wellness visits again.
Whatever the time period, children older than 12 months who had a wellness visit were much more likely to be vaccinated than those who didn't (91.2% vs 8.8%). But wellness visits decreased from 76.2% to 70.9% during the pandemic, and measles vaccinations of children with no wellness visits after age 12 months decreased from 9.7% before the pandemic to 2.5% after clinics reopened for in-person visits.
Black and white children (as compared with Hispanic and Asian children) and those without health insurance were the least likely to be vaccinated. However, despite the difference in measles vaccination between black and white patients in the unadjusted analyses, there was no difference after adjustment for insurance coverage and time period. Neither was there significant correlation between race and health coverage in the likelihood of vaccination.
Lead author Sara Bode, MD, said in a Nationwide Children's Hospital news release that skipping or delaying measles vaccinations has led to recent outbreaks of the disease. "We have seen a resurgence of measles outbreaks in the U.S. and here in Ohio in recent years because fewer people have chosen to immunize," she said.
Coauthor Alex Kemper, MD, MPH, MS, said in the release that it is now safe to take children to clinics for preventive care and vaccinations and that his care network is working with community wellness organizations and schools to offer catch-up vaccinations, including mobile alternatives and pop-up events.
"We are doing a lot of work to let our patients and families in the community know it is safe to come in for wellness visits," Kemper said. "We have prioritized these visits and opened up additional appointment slots throughout the day and evening."
Bode added that, while vaccination is important, children have other issues that need evaluation at regular wellness visits, including growth and development, mental health, nutrition, and physical activity. "Even though we are in a pandemic, child well care visits are safe and important—in fact it is unsafe [to] miss these needed services for your child," she said.
