Increase in vaccine-preventable disease outbreaks threaten years of progress, warn WHO, UNICEF, Gavi

GENEVA: Immunisation efforts are increasingly at risk as misinformation, population growth, ongoing humanitarian crises, and funding cuts jeopardise progress and leave millions of children, adolescents, and adults at risk, warned WHO, UNICEF, and Gavi during World Immunisation Week (April 24-30).

Outbreaks of vaccine-preventable diseases such as measles, meningitis, and yellow fever are rising globally, and diseases like diphtheria, which have long been held at bay or virtually disappeared in many countries, are at risk of re-emerging.

In response, the agencies are calling for urgent and sustained political attention and investment to strengthen immunisation programmes and protect significant progress achieved in reducing child mortality over the past 50 years.

“Vaccines have saved more than 150 million lives over the past five decades,” said WHO Director-General, Dr Tedros Adhanom Ghebreyesus. “Funding cuts to global health have put these hard-won gains in jeopardy. Outbreaks of vaccine-preventable diseases are increasing around the world, putting lives at risk and exposing countries to increased costs in treating diseases and responding to outbreaks. Countries with limited resources must invest in the highest-impact interventions – and that includes vaccines”, he added.

Measles is making an especially dangerous comeback. The number of cases has been increasing year on year since 2021, tracking the reductions in immunisation coverage that occurred during and since the COVID-19 pandemic in many communities. Measles cases reached an estimated 10.3 million in 2023, representing a 20% increase from 2022.

The agencies warn that this upward trend is likely to continue into 2024 and 2025, as outbreaks have intensified worldwide. In the past 12 months, 138 countries have reported measles cases, with 61 experiencing large or disruptive outbreaks — the highest number observed in any 12-month period since 2019.

Meningitis cases in Africa also rose sharply in 2024, and the upward trend has continued into 2025. In the first three months of this year alone, more than 5500 suspected cases and nearly 300 deaths were reported in 22 countries. This follows approximately 26,000 cases and almost 1400 deaths across 24 countries last year.

Yellow fever cases in the African region are also on the rise, with 124 confirmed cases reported in 12 countries as of 2024. This comes after dramatic declines in the disease over the past decade, thanks to global vaccine stockpiles and the use of yellow fever vaccine in routine immunisation programmes. In the WHO Region of the Americas, yellow fever outbreaks have been confirmed since the beginning of the year, with a total of 131 cases reported in four countries.

These outbreaks come amidst global funding cuts. A recent WHO rapid stocktake with 108 country offices of WHO, mostly in low- and lower-middle-income countries, shows that nearly half of these countries are facing moderate to severe disruptions to vaccination campaigns, routine immunisation, and access to supplies due to reduced donor funding. Disease surveillance, including for vaccine-preventable diseases, is also impacted in more than half of the countries surveyed.

At the same time, the number of children missing routine vaccinations has been increasing in recent years, even as countries make efforts to catch up on children missed during the pandemic. In 2023, an estimated 14.5 million children missed all of their routine vaccine doses–up from 13.9 million in 2022 and 12.9 million in 2019. Over half of these children live in countries facing conflict, fragility, or instability, where access to basic health services is often disrupted.

“The global funding crisis is severely limiting our ability to vaccinate over 15 million vulnerable children in fragile and conflict-affected countries against measles,” said UNICEF Executive Director Catherine Russell. “Immunisation services, disease surveillance, and outbreak response in nearly 50 countries are already being disrupted, on par with the setbacks we saw during COVID-19. We cannot afford to lose ground in the fight against preventable disease.”

Continued investment in the ‘Big Catch-Up initiative,’ launched in 2023 to reach children who missed vaccines during the COVID-19 pandemic, and other routine immunisation programmes will be critical.

Joint efforts by WHO, UNICEF, Gavi and partners have helped countries expand access to vaccines and strengthen immunisation systems through primary health care, even in the face of mounting challenges. Every year, vaccines save nearly 4.2 million lives against 14 diseases, with nearly half of these lives saved in the African region.

Vaccination campaigns have led to the elimination of meningitis A in Africa’s meningitis belt. A new vaccine that protects against five strains of meningitis holds promise for broader protection, with efforts underway to expand its use for outbreak response and prevention.

Progress has also been made in reducing yellow fever cases and deaths through increasing routine immunisation coverage and emergency vaccine stockpiles, but recent outbreaks in Africa and in the Region of the Americas highlight the risks in areas with no reported cases in the past, low routine vaccination coverage and gaps in preventive campaigns.

In addition, the past two years have seen substantial progress in other areas of immunisation. In the African region, which has the highest cervical cancer burden in the world, HPV vaccine coverage nearly doubled between 2020 and 2023 from 21% to 40%, reflecting a concerted global effort towards eliminating cervical cancer. The progress in immunisation also includes increases in global coverage of pneumococcal conjugate vaccines, particularly in the South-East Asia Region, alongside introductions in Chad and Somalia, countries with high disease burden.

Another milestone is the sub-national introduction of malaria vaccines in nearly 20 African countries, laying the foundation to save half a million additional lives by 2035 as more countries adopt the vaccines and scale-up accelerates as part of the tools to fight malaria.

UNICEF, WHO, and Gavi urgently call for parents, the public, and politicians to strengthen support for immunisation. The agencies emphasise the need for sustained investment in vaccines and immunisation programmes and urge countries to honour their commitments to the Immunisation Agenda 2030 (IA2030).

As part of integrated primary healthcare systems, vaccination can protect against diseases and connect families to other essential care, such as antenatal care, nutrition or malaria screening. Immunisation is a ‘best buy’ in health with a return on investment of USD 54 for every dollar invested and provides a foundation for future prosperity and health security.

“Increasing outbreaks of highly infectious diseases are a concern for the whole world. The good news is we can fight back, and Gavi’s next strategic period has a clear plan to bolster our defences by expanding investments in global vaccine stockpiles and rolling out targeted preventive vaccination in countries most impacted by meningitis, yellow fever and measles,” said Dr Sania Nishtar, CEO of Gavi, the Vaccine Alliance. “These vital activities, however, will be at risk if Gavi is not fully funded for the next five years and we call on our donors to support our mission in the interests of keeping everyone, everywhere, safer from preventable diseases.”

Gavi’s upcoming high-level pledging summit, taking place on June 25, 2025, seeks to raise at least USD 9 billion from our donors to fund our ambitious strategy to protect 500 million children, saving at least 8 million lives from 2026-2030. (ANI)