WHO WATCH: Outcomes of the Strategic Advisory Group of Experts on Immunization (SAGE) Meeting

Highlights

Cross-cutting statements

During the last months, the world has witnessed a range of shifts that have profoundly impacted the health and development sectors.
The current political and societal developments jeopardize global health, including vaccination programmes worldwide.
SAGE underlined the major contribution of vaccination to improved global child survival and health, while being one of the public health measures with the highest returns on investment.
SAGE expressed its deep concern about the current situation with the diversion of resources away from public health, which creates a risk of further backsliding just when countries are recovering from the impact of the COVID-19 pandemic. This could adversely affect the ability of global immunization programmes to sustain the tremendous gains it has made and progress towards the goals of the Immunization Agenda 2030 (IA2030).

Session 1: Global & regional reports

Report from the Department of Immunization, Vaccines, and Biologicals

The report underscored the massive impact and progress made in global immunization to save lives and enhance health while acknowledging the unprecedented challenges ahead.
As requested by SAGE, the report provided detailed insight into WHO’s role in accelerating critical opportunities and overcoming key gaps that will enhance the impact of vaccination.
Specific areas across the immunization value chain included WHO’s role in the TB vaccine accelerator, strengthening vaccine regulatory capacity, regionalization of vaccine manufacturing, accelerating the rapid introduction and scale-up of malaria and HPV vaccines, innovations to break through the glass ceiling on immunization coverage, and reaching unvaccinated communities.
However, the report also highlighted the severe strain and threat to immunization programmes at global, regional and country levels with recent abrupt changes in donor budgets and capacity in global health and decreases in fiscal space domestically.
Most prominent are the threats to measles vaccine coverage improvements, disease surveillance, laboratory networks and outbreak response capacity, which are being acutely affected by budget cuts. WHO continues to provide leadership, coordination, country support and capacity strengthening as part of the Measles and Rubella Partnership, making all possible efforts to avert increases in preventable cases and deaths across countries that will result if the threats further materialize.
Through strategic prioritization, innovation, and global collaboration, WHO supports countries in building resilient, equitable, and sustainable immunization programmes now and for the next 50 years and beyond, to harness safe, affordable and effective vaccines.

Update from Gavi, the Vaccine Alliance

The Gavi strategy 2026-2030 (Gavi 6.0) will be launched in 2026 with a focus on introducing and scaling up new vaccines, strengthening country programmes, supporting optimization and prioritization processes, ensuring sustainability, providing tailored support, and reducing zero-dose children.
The HPV initiative is on track to immunize 86 million girls by 2025, and significant progress has been made in rolling out malaria vaccines.
Gavi's new Health Systems Strategy focuses on equitable and sustainable immunization efforts through differentiated country support, consolidated funding, innovations, partnerships, and improved measurement.
Polio eradication remains a priority, with Gavi investing US$ 800 million in inactivated polio vaccines under the current strategy (Gavi 5.0), and the hexavalent vaccine[1] introductions planned for this year.
Gavi has allocated US$ 5.6 million to address the mpox crisis and looks forward to establishing a vaccine stockpile as part of Gavi 6.0 and document how the vaccine can contribute to broader disease control efforts.
In 2024, Gavi approved 49 outbreak response requests and plans to support the use of diagnostics to strengthen data availability and decision-making. Regional reports
Three regional reports highlighted the resurgence of measles and the need for urgent actions to mitigate the risk of large outbreaks while noting the challenges with improving routine coverage and timely preventive vaccination activities. The problems could be further exacerbated with a shift in resources away from health, if current programme performance cannot be sustained, let alone further enhanced. The number of zero-dose children has increased in some regions even after the restoration of routine immunization programmes following the COVID-19 pandemic response. While the Big Catch-up has helped, it has only partially addressed the problem and further efforts are required to fill immunity gaps.
The report from the South-East Asian Region struck a positive note and reported on the successes with scaling up HPV vaccination; SAGE recommendations for the use of a single-dose schedule have made an important contribution to the scale-up.

Session 2: Immunization Agenda 2030 (IA2030): country-led monitoring

Though many countries remain off track against key metrics for measuring progress against IA2030 indicators, there have been notable achievements such as the Big Catch-up and the scale-up of malaria and HPV vaccination.
The IA2030 Partnership Council has proposed three pivots in the IA2030 strategy: to increase advocacy, enhance a country-centred approach, and intensify inter-agency partnership and collaboration.
A review of 51 national immunization strategy (NIS) documents from low- and middle-income countries showed that countries are setting specific targets to reach IA2030 goals. Linkages to primary health care have been strengthened and NISs are increasingly being used to demonstrate country ownership and for resource mobilisation.
The NIS is an opportunity to strengthen country data use for monitoring programme performance, implementing action cycles for programme improvement, and increasing accountability.
Immunisation data systems in many countries lack the granularity, context, nuance or perspicacity to inform actions required to improve programme performance.
Country-centred, continuous quality improvement processes supported by sufficiently capacitated WHO Regional and Country Offices, along with key partner engagement, are required to enable the required changes in programme monitoring.

Session 3: Pneumococcal vaccination of children

SAGE reaffirmed that achieving high coverage of three doses of pneumococcal conjugate vaccines (PCVs) using either a 3p+0[2] or a 2p+1[3] schedule is the most effective way to prevent childhood pneumococcal disease. An update to the review of evidence from 2019, continued to show no conclusive advantage for either schedule over the other; the choice of schedules should be based on local epidemiological and programmatic factors.
In addition to two currently WHO-prequalified vaccines, PCV10 (Synflorix ®, GlaxoSmithKline) and PCV13 (Prevenar13®, Pfizer), recent evidence supports the use of a third WHO-prequalified PCV10 (Pneumosil®, Serum Institute of India) for routine immunization of infants using either of the two recommended 3-dose schedules.
Countries considering switching to recently licensed higher valency PCV product (e.g., PCV14, PCV15, PCV20) to broaden serotype coverage must consider trade-offs that may exist, particularly the potential reduced direct and indirect protection against serotypes in common with PCV10 / PCV13, noting that antibody concentrations tend to be reduced as the number of serotypes in the product increases.
Countries with mature PCV programmes that have achieved adequate levels of herd immunity can consider one of two cost-saving strategies: (i) the use of a reduced dose 1p+1 schedule[4]; or (ii) the use of a 40% fractional dose of PCV13 (the only product for which evidence supported fractional dose use). Both strategies require high vaccination coverage, and careful impact and coverage monitoring with contingency plans to revert to full 3-dose schedules if indicated.
In settings with evidence of or suspected insufficient population immunity (e.g., high disease burden, persistently low vaccination coverage, and humanitarian emergencies), multi-age cohort (MAC) campaigns with a single dose of PCV should be considered; MAC campaigns should not replace or divert resources from routine programmes for immunization with PCVs.
Establishing capacity for pneumococcal surveillance (disease and/or carriage) in early-adopter countries, ideally a few representative surveillance sites in each WHO region, is desirable to generate real-world evidence of the effectiveness of new pneumococcal vaccines and alternative dosing strategies.

Session 4: Mpox

A second mpox public health emergency of international concern (PHEIC) was declared in August 2024 related to the emergence of a new virus clade (Ib), and its spread across African countries. While mpox continues to be reported in all WHO Regions, the number of cases is increasing in Africa. 
Five African countries have initiated vaccination and over 582 000 vaccine doses have been administered in the Democratic Republic of the Congo alone as of 16 March 2025. However, with the acceleration of vaccination activities, vaccine supply is again constrained.
Current WHO recommendations allow for the “off-label” use of a single dose or an intradermal fractional dose of MVA-BN in supply-constrained outbreak situations; SAGE recommended consideration of these strategies if indicated.
SAGE noted that while pre- and post-exposure vaccination to control the ongoing outbreak was appropriate under the current circumstances, the next phase should focus on preventive vaccination. However, evidence gaps remain to inform strategies for preventive vaccination implementation, and research is ongoing to fill these gaps. 
SAGE expressed concern about reduced funding for HIV/AIDS control programmes, which could lead to a resurgence of HIV infections and a rise in the number of people living with undiagnosed or uncontrolled HIV, who are particularly vulnerable to severe mpox.

Session 5: Varicella & Herpes Zoster

Varicella and herpes zoster cause significant morbidity worldwide. The cost-effectiveness of vaccination based on current vaccine prices would vary between countries and would only be considered cost-effective in most countries based on overall economic benefits, including productivity loss of caregivers.
SAGE recommended that the use of varicella vaccines using a 2-dose schedule with a minimum 4-week interval between doses be considered for the prevention of varicella in children in populations where varicella is an important public health problem.
Countries introducing the varicella vaccine should define vaccination coverage targets, guided by criteria including national and subnational disease burden, affordability, cost-effectiveness, seroprevalence rates and age of infection acquisition to avoid the theoretical risk of a shift in the age of infection resulting in higher morbidity if coverage is low or modest.
SAGE also recommended consideration of varicella vaccination of special populations, including certain groups who are at risk for severe disease. Vaccination may be offered to immunocompromised and those living with well-controlled HIV infection and adequate CD4 counts.
Further, vaccination is recommended for health care workers without documented evidence of prior VZV infection or vaccination. The aim is to avoid onward transmission to susceptible patient groups, particularly when caring for immunocompromised persons, as well as for personal protection, particularly if caring for children.
SAGE recommended that the use of the recombinant herpes zoster vaccine in a 2-dose schedule with a minimum 2-month interval between doses, for the prevention of herpes zoster in older adults, those with chronic conditions and the immunocompromised, be considered in countries where herpes zoster is an important public health problem. SAGE advised countries to conduct cost-effectiveness analyses to inform decision-making.

Session 6: Global progress in the National Immunization Technical Advisory Group (NITAG) strengthening

There has been remarkable progress with the establishment and functionality of NITAGs globally. However, NITAGs in many middle-income countries face challenges that impede optimal functionality, including inadequate secretariat support. SAGE noted the increasing importance of NITAGs in advising governments on vaccine introduction prioritization, vaccine portfolios and immunization schedules optimization, as well as their role in programme monitoring.
SAGE encouraged efforts to sustain and further enhance the capacity of NITAGs, advocated for periodic evaluations of their capacity and functioning, and reiterated the need for sub-regional immunization technical advisory groups to serve countries with small populations and inadequate breadth of technical capacity.
SAGE called for countries to demonstrate their commitment to NITAGs by increasing domestic funding to support the NITAG secretariats and their operations, including through enacting legislation that recognizes the role, importance and functionality of NITAGs.
SAGE applauded the strong coordination of NITAG support through the Global NITAG Network and called on WHO and partners to continue supporting this initiative.

Session 7: Prioritization of new vaccine introduction

In the context of an increasing number of available vaccines, SAGE emphasized that each country should be empowered to prioritize these vaccines and determine the timing of the introduction of the vaccines into national programmes. These decisions should be made using a systematic, country-owned process based on the local context.
SAGE acknowledged that NITAGs play a crucial role in leading a deliberate evidence-based approach leveraging available tools such as multi-criteria decision analysis (MCDA) and engaging relevant stakeholders.
SAGE called on countries to engage their NITAG in providing recommendations on the prioritization of new vaccines for introductions and optimization of vaccination schedules and portfolios in close consultation with their respective national immunization programmes. These recommendations need to be aligned and integrated with the priorities in their NIS and health sector strategy and regularly updated.
SAGE noted the challenges countries face with access to evidence to support informed choices and called on WHO and all partners to strengthen coordination in this area.

Session 8: Poliomyelitis

SAGE was highly concerned about the continued transmission of wild poliovirus in Pakistan and Afghanistan and the overall lack of efforts towards a transformative change in strategy to complete poliovirus eradication.
SAGE expressed concern about the continued circulation of vaccine-derived poliovirus type 2 and its expansion into new areas, including European countries as demonstrated by environmental surveillance, and stressed the urgent and compelling need for increased improvements in routine immunization coverage and to reach zero-dose children with catch-up doses. SAGE reiterated its support for the safe eventual global cessation of bOPV and agreed with plans for pre-cessation bOPV vaccination campaigns based on the proposed methods to determine the need for such campaigns.
SAGE endorsed the proposed risk-grading framework as a guide for discussions with countries considering transitioning to IPV-only routine immunization schedules in advance of a global bOPV withdrawal and urged WHO to initiate consultations on this topic with its Member States and Regional Offices.
SAGE reviewed updated evidence and concluded that a polio vaccination schedule with a minimum of three doses of the IPV (-containing) vaccine, such as the IPV-containing whole-cell pertussis hexavalent vaccine, starting at 6 weeks of age or later is adequate, without the need for a scheduled IPV booster dose (4th dose) and revised existing recommendations accordingly. However, SAGE emphasized that if schedules do not programme a 4th dose as a booster (which may serve as a possibility to catch-up children that have missed previous doses), it is essential that children receive all 3 doses. This recommendation does not change WHO’s existing recommendations for providing booster doses of other antigens in the second year of life, namely diphtheria-tetanus-pertussis containing vaccines.

[1] Containing diphtheria toxoid, tetanus toxoid, whole-cell pertussis, recombinant hepatitis B surface antigen, Haemophilus influenzae type b (Hib) conjugate and inactivated poliovirus vaccines.

[2] 3 primary doses without a booster dose

[3] 2 primary doses with 1 booster dose

[4] 1 primary dose with 1 booster dose

*The opinions expressed by the hosts and guests in this show are not necessarily the views of Children’s Health Defense.

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