A side effect of the COVID-19 pandemic: widespread disruptions of routine vaccination

Published July 14, 2021

The COVID-19 pandemic resulted in disruptions to routine health services around the world, including childhood vaccinations. IHME researchers produced two papers measuring global coverage of routine childhood vaccinations from 1980 to 2019 and throughout 2020, revealing the disruptions caused by the COVID-19 pandemic. Find links to these papers and additional resources below.


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The Lancet: COVID-19 pandemic interrupted routine vaccinations for at least 17 million children worldwide in 2020, modelling study suggests


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Professor Jon Mosser: Childhood immunization has been one of the greatest public health success stories over the past several decades. What we know is that childhood immunizations are safe, they’re effective, and they’ve played a major role in reducing childhood mortality since the 1980s when they became broadly available in a large number of countries.

Kate Causey, Lead Author: In this paper, we found large and widespread disruptions across the globe. We estimate relative reductions of about 8% to both MCV1 and DTP3, relative to what we would’ve expected vaccine coverage levels to be in the absence of COVID-19. 

The most severe disruptions in this analyses were in April of 2020, with relative disruptions of over 30% for both vaccines. Nearly 9 million children missed doses of each vaccine over the course of 2020 because of the COVID-19 pandemic. Disruptions occurred in every GBD super-region, with strongest pandemic-related effects in North Africa, the Middle East, and South Asia; the smallest effects were in sub-Saharan Africa. Because there is lower coverage to start with in sub-Saharan Africa, there is still a large number of children there who likely missed vaccinations in 2020.

As COVID-19 continues to spread, it’s essential we make dedicated efforts to maintain strong, routine immunization services and to catch-up children who missed doses to prevent outbreaks of measles and other vaccine-preventable diseases. It’s going to be important as we move beyond the COVID pandemic eventually to think about how not just to return to our pre-pandemic services but also expand the coverage of vaccination so we can reach all children. We know that as coverage has stagnated over the past decade, there are still many children even before the pandemic who missed out on the life-saving benefits of vaccination. 

Professor Jon Mosser: This is an opportunity for the global immunization community and immunization programs at country levels and local levels to rethink the way that they deliver vaccinations so that we can ensure all kids benefit from access to vaccines. 

Transcript 

Professor Jon Mosser: It's important to understand the trajectory of vaccination coverage over time and patterns and trends that have emerged, especially leading up to 2020, which was a historic year of challenges for immunizations systems. So in the manuscript that was published in The Lancet, we look at patterns in immunization coverage by country and at regional and global levels over time to understand where the success stories have occurred, but also to understand the magnitude of challenges that have persisted – particularly over the last decade – and to set the stage for understanding how to move forward as an immunization community worldwide, from 2020 and beyond.

Natalie Galles, Post-Bachelor Fellow at IHME: In this work, we evaluated trends in vaccination coverage for 11 childhood vaccines between 1980 and 2019. Globally, we found that substantial gains in coverage have been made. Coverage of third dose of diphtheria, tetanus, pertussis and first dose measles approximately doubled from 1980 to 2019, rising to levels of 81.6% and 83.6%, respectively. Coverage of relatively newer vaccines such as third-dose Hepatitis B and third-dose Haemophilus influenzae Type B also showed significant global gains since their introduction.

Patrick Liu, Researcher: However, particularly since 2010, continued advancements in coverage stalled or reversed in many countries. For instance, 94 countries experienced declining DTP3 coverage between 2010 and 2019 – the largest declines in Latin America and the Caribbean.

Natalie Galles, Post-Bachelor Fellow at IHME: We also used our estimates to benchmark progress toward national coverage targets in the 2020 Global Vaccine Action Plan. We found that only 11 countries and territories reached at least 90% national coverage across all vaccines by 2019.

Patrick Liu, Researcher: Together, these results highlight the critical need for bolstered, context-specific, and equitable vaccine delivery strategies, if the targets set forth by the Immunization Agenda 2030 are to be met by the end of this decade.

 

Transcript 

Professor Jon Mosser: It's also been increasingly challenging over the past decade to reach every child with necessary vaccinations. So we know that vaccination coverage has largely stagnated. In some cases, the trends of improvement we've previously seen have reversed over the last decade as well. 

Natalie Galles, Post-Bachelor Fellow at IHME: We also used our estimates to estimate counts of zero-dose children, approximated by the number of children estimated to have never received their first dose in the DTP series. 

Patrick Liu, Researcher: While the number of estimated zero-dose children fell by nearly 75% since 1980, a total of 14.5 million children did not receive even the first dose of DTP in 2019. 

Professor Jon Mosser: The Immunization Agenda 2030 contains a new and increasing emphasis on this concept of zero-dose children, who are children who do not have access to routine immunization services. So it's going to be important to identify those children and figure out how to reach them in the decades to come.


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