Pandemic & Infectious Disease — 2026-04-24

Active Outbreak Tracker

Respiratory Virus Activity — United States

• Status: As of April 17, 2026, the amount of acute respiratory illness causing people to seek health care is very low, per CDC tracking.
• Key Development: Despite low current activity, a federal court ruling last month halted the Kennedy-led vaccine advisory panel, leaving COVID shots and newer vaccines in a state of uncertainty. Americans may face the next respiratory disease season without clear guidance for COVID shots and updated flu vaccines, raising questions about insurance coverage for newly approved products.
• Response: CDC continues publishing real-time Rt estimates and respiratory illness data at the state and national level. The agency's Center for Forecasting and Outbreak Analytics (CFA) is maintaining surveillance models.

CDC EIS Conference — United States

• Status: Active, gathering disease detectives this week (April 2026).
• Key Development: CDC's Epidemic Intelligence Service (EIS) officers convened for their annual 2026 EIS Conference, presenting findings from disease investigations carried out over the past year. The conference is a key venue for sharing epidemiological intelligence and fostering collaboration among public health professionals.
• Response: CDC highlighted the conference as part of its ongoing commitment to field epidemiology training and disease outbreak response capacity.

4 sources

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Current Outbreaks | Foodborne Outbreaks | CDC

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Global Measles Outbreaks | Global Measles Vaccination | CDC

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Global Health Funding Crisis — Worldwide

• Status: Ongoing; WHO flagged measurable impact from funding constraints in its 2025 Results Report released April 23, 2026.
• Key Development: Despite significant funding cuts affecting WHO and the broader global health sector, the organization reported supporting substantial national health gains for hundreds of millions of people in 2025. The report noted progress under WHO's Thirteenth General Programme of Work, even as resource pressures continue.
• Response: WHO released the 2025 Results Report to document outcomes and make the case for sustained funding. UN News reported that billions of people saw health gains during the year, though structural vulnerabilities remain.

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Vaccine & Treatment Pipeline

• VYD2311 Monoclonal Antibody (Invivyd): The FDA has agreed to the design of a Phase 3 trial evaluating the safety and immunology of Invivyd's monoclonal antibody VYD2311 versus mRNA COVID vaccines and in co-administration — a potentially significant alternative pathway for COVID-19 protection.

• COVID-19 Vaccine Antigen Composition (WHO TAG-CO-VAC): The WHO Technical Advisory Group on COVID-19 Vaccine Composition continues monitoring SARS-CoV-2 variants and vaccine performance ahead of May 2026 deliberations on updated antigen composition. Strain selection decisions made in May will shape the next generation of COVID vaccine formulations.

• TB Vaccine Candidates — PreVenTB Trial (multiple developers): A Phase 3 trial conducted in India found that two experimental TB vaccine candidates did not demonstrate efficacy against all forms of TB, though they were safe and offered limited protection against a more severe form of the disease. GlobalData epidemiologists project TB cases in 16 major markets to reach 4.5 million by 2033, underscoring the ongoing urgency of TB vaccine development.

Expert Analysis

The most pressing development this week is the legal and political disruption to U.S. vaccine guidance. A federal court ruling last month halted the Kennedy-led vaccine advisory panel, leaving COVID and flu vaccine recommendations for the upcoming respiratory season in an uncertain state. Reuters reported that "Americans may face the next respiratory disease season without clear guidance for COVID shots and updated flu vaccines," noting that the ruling raises questions about whether "some newly approved products would be covered by insurers." This creates a dual burden: patients may not know what vaccines to get, and insurers may decline to cover updated shots. Public health officials warn this scenario could depress vaccination rates at a time when immunity gaps remain a global concern.

On the global stage, the WHO's 2025 Results Report — released April 23 — documented remarkable resilience in global health systems despite funding pressures. According to the UN, "billions saw health gains in 2025 despite funding cuts," but the organization was careful to note that these gains were achieved under strain. The report reflects a transition to a new WHO strategy, and the George W. Bush Presidential Center's Global Health Update (April 23) flagged malaria as a particular area of concern given ongoing resource constraints in sub-Saharan Africa.

The TB vaccine pipeline setback also drew attention this week. The PreVenTB Phase 3 trial in India found limited protection from two experimental candidates, reinforcing what many experts have long argued: TB remains one of the most neglected and technically challenging diseases to vaccinate against. With projected cases rising to 4.5 million by 2033 in major markets, the global health community faces a long road ahead.

Global Health Security

WHO 2025 Results Report signals strategic shift under funding pressure. The WHO released its annual Results Report on April 23, 2026, documenting health gains achieved in 2025 under its Thirteenth General Programme of Work — even as funding cuts from major donor nations, including the United States, have constrained its operations. The report is seen as a statement of resilience and a pitch for continued investment ahead of the next programming cycle.

U.S. court ruling creates vaccine advisory vacuum. A federal court last month halted the Kennedy-led advisory panel that traditionally provides vaccine guidance in the United States. The ruling has left the status of COVID shots and newer vaccines unclear for the upcoming respiratory season, with implications for both public health communication and insurance coverage of newly approved products.

CDC EIS Conference convenes disease detectives. The CDC's 2026 Epidemic Intelligence Service Conference brought together field epidemiologists to present findings from the past year's outbreak investigations. The annual gathering is a cornerstone of U.S. public health surveillance capacity and international disease intelligence sharing.

What to Watch Next

• WHO May 2026 COVID vaccine antigen composition decision: The WHO Technical Advisory Group on COVID-19 Vaccine Composition (TAG-CO-VAC) will convene in May 2026 to deliberate on strain selection for the next round of COVID vaccines. This decision will shape what manufacturers produce and what updated shots are available ahead of the next respiratory season — especially important given the current U.S. advisory panel vacuum.

• U.S. vaccine guidance resolution: The federal court ruling that halted the Kennedy-led advisory panel remains unresolved. Watch for legal appeals, legislative action, or interim guidance from HHS or CDC that could clarify the status of COVID and flu vaccine recommendations before the fall respiratory season begins.

• TB vaccine pipeline: With the PreVenTB Phase 3 trial results showing only limited protection, attention will shift to other TB vaccine candidates in the pipeline and whether any can clear the bar for efficacy. GlobalData projects TB cases could reach 4.5 million by 2033 in major markets — making the next trial readouts among the most consequential in global infectious disease research.