Veronica Paulus , 2025-06-24 22:30:00
Childhood vaccination coverage has made leaps since 1980. But progress has significantly slowed in the last two decades.
That is according to a study published in The Lancet Tuesday, which found stagnation and wide variation in childhood vaccination rates since 2010. The study, which estimated childhood vaccination coverage between 1980 and 2023 in 204 countries and territories, found that the Covid-19 pandemic significantly intensified existing immunization challenges.
The findings come as Americans are experiencing an unprecedented surge in vaccine skepticism. This year’s total measles case numbers will be the highest in more than three decades. Another recent study suggested that if the country maintains its current immunization levels, it will likely lose its measles elimination status.
The resurgence occurs as the Trump administration has slashed federal research funding dollars, appointed vaccine critics to a key panel that advises the Centers for Disease Control and Prevention on federal vaccination recommendations, and is increasingly balkanizing the country’s immunization policy.
The Lancet study did not take into consideration the effects of the shifting U.S. vaccine landscape, since the analysis was completed before these developments occurred, according to senior study author Jonathan Mosser.
“Even without accounting for these effects, our analysis suggests that a substantial acceleration in progress would be needed to reach global targets and ensure high, equitable coverage in all countries,” said Mosser, a professor at the University of Washington’s Institute for Health Metrics and Evaluation.
Stalled progress in vaccination coverage in the past two decades could derail the World Health Organization’s global immunization goals for 2030, according to the study’s authors. One of WHO’s goals is to reduce the number of zero-dose children (those who have never received a routine childhood vaccine) by half, compared with 2019 levels. Another is to achieve 90% coverage for vaccinations such as the diphtheria-tetanus-pertussis vaccine.
“There are substantial challenges in reaching global targets set for 2030, with the world — and most countries — off pace,” Mosser said.
To estimate coverage of 11 childhood vaccinations, researchers applied a combination of statistical modeling approaches to synthesize data from more than 1,000 sources, primarily pulling information from a WHO-UNICEF form and large-scale household surveys. The group also conducted secondary analyses focused on the impact of the Covid pandemic and the feasibility of achieving the WHO’s immunization goals.
“The estimates are quite credible and realistic,” said Art Reingold, a professor of epidemiology at the University of California, Berkeley School of Public Health who was not involved in the study. “I don’t know that you could, in the real world, do any better than what they’re doing.”
The study revealed “a remarkable long-term success” in global routine childhood vaccination, according to Mosser. Between 1980 and 2023, global vaccine coverage doubled against diphtheria, tetanus, whooping cough, measles, polio, and tuberculosis. And between 1980 and 2019, there was a 75% global decrease in the number of zero-dose children.
But this progress slowed significantly between 2010 and 2019, even before the onset of the pandemic. In 21 of 36 high-income countries, coverage for at least one vaccine dose against diphtheria, tetanus, whooping cough, measles, or polio declined. And the proportion of children receiving the measles vaccine fell in 100 countries during this period.
“We kind of got the low-hanging fruit prior to 2010,” said William Moss, a professor of epidemiology at Johns Hopkins University’s Bloomberg School of Public Health who was not involved in the study. “That remaining group of children — it’s just been very difficult despite efforts to reach those children.”
Moss cited two factors that make vaccinating this group of children particularly difficult. The first is access: Many of these children live in remote rural areas, in densely populated urban settings that are difficult to reach, or in conflict-affected areas where entire immunization systems are disrupted. Mosser echoed Moss’ explanation, adding that geopolitical instability and natural disasters also disrupt vaccination efforts.
The second reason Moss highlighted relates to demand. The growing threat of vaccine hesitancy and misinformation has eroded public confidence in immunization effectiveness, particularly in higher-income countries.
And the pandemic has only exacerbated these trends. Following its onset, global vaccination rates declined and had not returned to pre-pandemic levels by 2023. The number of zero-dose children peaked at 18.6 million in 2021, rising from 14.7 million in 2019 — adding an estimated 12.8 million unvaccinated children worldwide during the four pandemic years.
The analysis also found that vaccination challenges disproportionately affected low- and middle-income countries. Over 50% of the 15.7 million zero-dose children live in eight countries: Nigeria, India, the Democratic Republic of Congo, Ethiopia, Somalia, Sudan, Indonesia, and Brazil.
“The pandemic placed extraordinary pressure on health systems, disrupted supply chains, and limited access to services due to physical distancing measures and health system diversions,” Mosser told STAT. Though the impact of the pandemic was profound, Mosser and his team projected much larger decreases in coverage when they first analyzed its potential effects in 2020.
“The fact that we haven’t seen even larger disruptions is a testament to the coordinated work of the global vaccination community,” Mosser said, adding that significant progress is still needed to recover from the pandemic’s impact.
The study also found that meeting the WHO’s 2030 immunization targets was unlikely — only the diphtheria-tetanus-pertussis vaccine was likely to achieve 90% coverage by 2030, and that, too, is an optimistic scenario.
And factors like increasing population pressure and cuts in global immunization funding only pose further risks to the progress of vaccination programs. Because the study’s analysis took place prior to the shifts in U.S. federal funding, such as to USAID, the authors were not able to incorporate their effects into their projections, according to Mosser.
“The situation is even more challenging, I think, in the coming years than is even outlined in this analysis,” Moss told STAT.
In addition to not including changes to global immunization funding, the authors noted other limitations. They were not able to take into account vaccinations administered outside routine schedules or catch-up vaccination activities. And though they used a statistical framework to estimate the pandemic’s impact on vaccination coverage, they relied on assumptions that could impact the estimation of effects, particularly in data-sparse regions, according to Mosser.
Reingold, the epidemiology professor at UC Berkeley, said that the implications of failing to meet the WHO’s immunization targets are immense.
“The bottom line is, we have only eradicated two infectious diseases in the world, only one of which affects humans, and that’s smallpox,” Reingold said. “Whatever progress we’ve made could be reversed if we don’t maintain and build on our successful immunization efforts to date.”
