# Presentation: 627360

## The Draft HHS Pandemic Influenza Preparedness and Response Plan: Vaccine & Antiviral Issues

- Ben Schwartz, M.D.
- National Vaccine Program Office
- Department of Health and Human Services

## Presentation Outline

- Pandemic response goals and the role of vaccine and antivirals
- Antiviral strategies in the draft HHS plan
- General principles, prophylaxis & treatment
- Questions for the subgroup
- Vaccine strategies in the draft HHS plan
- Vaccine supply

## Pandemic Influenza Response Goals

- Limit morbidity and mortality from influenza and its complications
- Decrease social disruption and economic loss

## Pandemic Response Actions:

- Time

- Impact

- Pandemic influenza disease

- Timing and Potential Impacts

- Vaccination

## Antiviral Planning Assumptions

- Only drugs that have been stockpiled will be available for public sector use
- Limited NI annual use and drug in the pipeline
- No current U.S. supply chain
- Resistance makes adamantane effectiveness uncertain
- Asian H5N1 strains in people have been resistant
- Resistance develops rapidly if adamantanes used as therapy

## Antiviral Planning Assumptions

- Antiviral drug use should not be considered as a strategy to alter the overall course of the pandemic
- Modeling data suggest that the quantity of antiviral drugs needed and implementation challenges make changing the pandemic course unlikely
- In an initial outbreak, containment strategies that include antiviral drug use may be effective
- Antiviral drug use may decrease the spread of illness early in a pandemic buying time for vaccine production and other response activities

## Overarching Principles of Antiviral Drug Use 

- Target antiviral drugs to defined priority groups based on pandemic response goals
- Maintain flexibility and responsiveness to local conditions
- Consider efficiency given that drug supply likely will be limited
- Use antiviral drugs appropriately to avoid the spread of resistance and to maximize effectiveness

## Guidance on Antiviral Prophylaxis

- Adamantanes are the preferred agents
- Greater supply
- Resistance develops with therapy so use should be reserved for prophylaxis
- Duration of prophylaxis
- During the period of a community outbreak
- Post-exposure prophylaxis possible in families and institutions
- Prophylaxis can be stopped 14 days after vaccination (1 or 2 doses, as needed)

## Guidance on Antiviral Prophylaxis

- Target groups
- Persons needed to maintain health care and public safety services
- Persons at high risk for severe illness
- Implementation
- State/local HDs define specific priority groups and distribution strategy before the pandemic
- Distribution of a partial course will enhance flexibility
- Communications on the rationale for targeting and education on compliance are critical
- Safety should be monitored

## Guidance on Antiviral Treatment

- Neuraminidase inhibitors preferred
- Effective in reducing complications
- Less risk of resistance developing
- Target groups
- Persons with more severe disease (hosp. admission)
- Persons at high risk based on epidemiology of the pandemic
- Essential service providers

## Guidance on Antiviral Treatment

- Implementation
- Deliver treatment at point-of-care – hospitals as critical delivery site staff, admitted patients, and high risk outpatients
- Treat as soon as possible and generally within 48 hrs of symptom onset
- Monitor for adverse events and development of resistance

## Questions on Pandemic Antiviral Strategies for the Subgroup

- Definition of specific target groups?
- Prophylaxis vs early treatment for HCWs and other essential service providers?
- Public sector stockpiling of adamantanes?
- NI treatment more than 48 hrs after symptom onset?
- Feasible distribution strategies?

## Pandemic Influenza Vaccines

## Vaccine Planning Assumptions

- Supply will be limited to what is produced in the U.S.
- Two doses will be required for protection

## Overarching Principles of Pandemic Vaccine Use

- Target vaccine to defined priority groups based on pandemic response goals
- Assure equitable distribution between racial and ethnic groups
- Significant disparities exist in coverage for annual influenza vaccination
- Maintain flexibility and responsiveness to local conditions
- High-risk groups in a pandemic may differ from those for annual influenza

## Pandemic Vaccine Supply Stages

| Supply stage | Key issues |
| --- | --- |
| 1 – No supply |  Duration depends on viral spread, season, and development & production timelines
 Intervene to slow pandemic spread  |
| 2 – Shortage  |  Target supply to priority groups
 Educate public on need for prioritization
 Monitor coverage & receipt of 2 doses
 Study effectiveness & monitor safety |
| 3 – Adequacy |  Vaccinate general population; assure equity |
| 4 – Excess |  Extend vaccine to other countries |

## Priority Groups for Pandemic Influenza Vaccine

- Base definition of target groups on response goals
- Maintain health care and vital services (e.g., public safety, groups implementing pandemic response)
- Protect persons at highest risk for influenza mortality
- Decrease transmission to those at highest risk (indirect protection)
- Maintain other important community services
- Protect the general population

## Implementation of Pandemic Influenza Vaccination

- Public sector role in vaccine purchase and distribution not yet determined
- Develop strategies to assure equity between racial and ethnic groups
- Develop educational materials to explain rationale for priority recommendations

## Monitoring and Evaluation

- Vaccine coverage
- Use local immunization registries – analyze to assess program effectiveness in targeting, delivering 2-doses, and achieving equity
- Implement systems that can generate reminders for the 2nd dose
- Vaccine effectiveness
- Vaccine safety
- National passive (VAERS) and active monitoring
- Develop strategies to prevent program disruption by coincidental events

## Questions on Pandemic Vaccine Strategies for the Subgroup

- Definition of specific target groups?
- Role of indirect protection within communities or on overall course of pandemic disease?
- Feasible distribution strategies?

## Pandemic Vaccine and Antiviral Drugs: Parallel or Complementary Strategies?

- Parallel strategies (belt and suspenders approach) – recommend similar groups in similar order
- Best assures protection of priority groups
- Easiest strategy to communicate
- Complementary strategies – recommend different groups to expand impacts
- Target antiviral drugs to reduce adverse health outcomes – esp. for populations less likely to respond to vaccine
- Target vaccine to decrease transmission and modify pandemic course