2022-07-13-世界卫生组织-Progress_and_challenges_with_Achieving_Universal_Immunization_Coverage_29页_3mb

报告摘要

Summary of Progress and Challenges with Achieving Universal Immunization Coverage

Core Content

The 2021 WHO/UNICEF Estimates of National Immunization Coverage (WUENIC) highlight significant challenges in maintaining immunization coverage globally, particularly due to the Covid-19 pandemic and associated disruptions. Despite efforts to expand vaccine access, the number of un- or under-vaccinated children increased to 25 million, a 2 million rise from 2020 and the highest since 2008. This decline is most pronounced in the WHO South-East Asian Region, where coverage dropped by 9% over two years.

Main Points

1. Vaccination Coverage Declined

DTP-3 coverage dropped to 81%, the lowest since 2008, leaving 25 million children vulnerable.
Measles vaccine coverage (MCV-1) also fell to 81%, resulting in 5 million more unvaccinated children compared to 2019.
The number of zero-dose children (those with no DTP dose) increased by 37%, from 13 to 18 million, the highest since 2005.

2. Regional Disparities

South-East Asia had the sharpest decline in immunization coverage, with a 9% drop over 2020–2021.
Other regions also experienced declines: 4% in the Americas, 3% in the Eastern Mediterranean, and 1% in Europe.
Zero-dose children are concentrated in low- and middle-income countries (LMIC), especially in Africa and South-East Asia.

3. Top 10 Countries with Most Unprotected Children

10 countries account for 62% of zero-dose children and 59% of those missing the first measles dose.
These include India, Indonesia, the Philippines, Myanmar, and others, with only the Democratic Republic of the Congo and Ethiopia classified as low-income.
LMICs are the main contributors, showing greater vulnerability to coverage setbacks.

4. Impact on Vaccine Introduction and Coverage

2021 saw the highest number of vaccine introductions in a single year, driven by Covid-19 vaccines.
Non-COVID vaccine introductions slowed significantly, with only 25 reported in 2021, down from 17 in 2020 and well below the long-term average of 50 per year.
HPV vaccine coverage declined by >15% since 2019, with only 12% of girls globally fully protected.

5. HPV Vaccine Challenges

HPV coverage in low- and middle-income countries (L&MIC) dropped further in 2021, with first dose coverage at 46% and final dose at 33%.
59% of cervical cancer cases occur in countries that have not introduced the HPV vaccine.
School closures and supply chain disruptions during the pandemic contributed to low HPV uptake in L&MICs.

6. Measles Outbreaks and Vulnerability

Measles outbreaks are increasing, especially in low- and middle-income countries, due to lower routine immunization and delayed campaigns.
MCV-2 (second measles dose) is not yet introduced in many African countries, contributing to lower coverage.

7. Yellow Fever Vaccine Coverage

YFV coverage in at-risk countries stood at 47% in 2021, which is too low to prevent outbreaks.
Supplementary campaigns are essential to maintain control of the disease.

8. Circulating Vaccine-Derived Poliovirus (cVDPV)

cVDPV cases increased sharply since 2019, highlighting immunization gaps.
WPV1 remains endemic in Pakistan and Afghanistan, but re-emerged in Africa in 2021 and 2022.

9. Need for Recovery and Catch-Up

Recovery efforts are critical to catch up on missed vaccinations and sustain immunization as an essential health service.
The Immunization Agenda 2030 (IA2030) aims to leave no one behind, with a target to reduce zero-dose children by half by 2030.
Catch-up vaccination and recovery strategies are emphasized, including guidance and technical resources from WHO and Gavi.

Key Information

25 million children were un- or under-vaccinated in 2021.
Zero-dose children increased by 37% since 2019.
Only 12% of girls globally are fully protected against cervical cancer due to low HPV coverage.
LMICs were more affected by the pandemic than higher-income countries (HICs).
Gavi support helped LMICs maintain coverage, but graduated countries saw sharper declines.
Supplemental Immunization Activities (SIAs) remain essential to reach under-vaccinated children.
2021 had the highest number of vaccine introductions, but coverage for other vaccines declined.
24 countries showed net improvements in immunization coverage between 2019 and 2021.
39 countries managed to recover in 2021, but only 24 saw improvement over two years.

Conclusion

The Covid-19 pandemic has significantly disrupted global immunization efforts, leading to worsening coverage and increased vulnerability to vaccine-preventable diseases. LMICs and African and South-East Asian regions are most affected, with zero-dose children and under-vaccinated populations rising sharply. Recovery and catch-up activities are crucial to meet the goals of IA2030 and ensure equitable access to immunization services. Technical resources and guidance are available to support immunization recovery and improve coverage.