Colorized transmission electron micrograph of Avian influenza A H5N1 viruses (seen in gold). Image provided by CDC/C. Goldsmith, J. Katz, and S. Zaki.

The CDC’s Plan for Rationing Antivirals and Vaccine During Pandemic Influenza

By Grattan Woodson, MD, FACP

The present ration plan for use during the next pandemic was published by the CDC in the fall of 2005 and adopted after a public comment period.1 The current plan focuses upon reserving the stockpiled Tamiflu and vaccine for individuals within specified groups. The tier ranking system is intended to reflect specific a individual’s relative risk of death and serious complications if affected by pandemic influenza and the costs to society of providing their care. Since pandemic influenza is a life and death issue, the formulation of this plan is tantamount to deciding who shall live and who shall die in advance. The plan raises many medical and thorny ethical issues as well as a lot of questions.

Interpreting the CDC priority list

The priority list is divided into 4 tiers and each tier is further subdivided into groups. Those in Tier 1, Group A are given the highest priority to scarce antiviral drugs and vaccines while those in Tier 4 will have the lowest priority meaning they will probably never get access to these agents. Below each tier in the list I have tabulated the sum of the persons included in that tier and at the bottom of the list is the total for all tiers. Since the current population of the US is 300 million and the total exceeds this by about 19 million people, there are some people represented more than once on the list. This is not an error, just a consequence of some people possessing one than one of the characteristics that place them on the list.

Below, is the official CDC order of priority with their rationale for them given below each group:

Tier 1
Group A
  • Vaccine and antiviral manufacturers and others essential to manufacturing and critical support (˜40,000)

Rationale: Needed to assure maximum production of vaccine and antiviral drugs

  • Medical workers and public health workers who are involved in direct patient contact, other support services essential for direct patient care, and vaccinators (8-9 million)

Rationale: Healthcare workers are required for quality medical care (studies show outcome is associated with staff-to-patient ratios). There is little surge capacity among healthcare sector personnel to meet increased demand.

Group B
  • Persons ≥ 65 years with 1 or more influenza high-risk conditions, not including essential hypertension (approximately 18.2 million)
  • Persons 6 months to 64 years with 2 or more influenza high-risk conditions, not including essential hypertension (approximately 6.9 million)
  • Persons 6 months or older with history of hospitalization for pneumonia or influenza or other influenza high-risk condition in the past year (740,000)

Rationale: These 3 groups are at high risk of hospitalization and death. Excludes elderly in nursing homes and those who are immunocompromised and would not likely be protected by vaccination
Group C
  • Pregnant women (approximately 3.0 million)

Rationale: In past pandemics and for annual influenza, pregnant women have been at high risk; vaccination will also protect the infant who cannot receive vaccine.
  • Household contacts of severely immunocompromised persons who would not be vaccinated due to likely poor response to vaccine (1.95 million with transplants, AIDS, and incident cancer x 1.4 household contacts per person = 2.7 million persons)
  • Household contacts of children < 6 month olds (5.0 million)

Rationale: Vaccination of household contacts of immunocompromised and young infants will decrease risk of exposure and infection among those who cannot be directly protected by vaccination.
Group D
  • Public health emergency response workers critical to pandemic response (assumed one-third of estimated public health workforce=150,000)

Rationale: Critical to implement pandemic response such as providing vaccinations and managing/monitoring response activities

  • Key government leaders

Rationale: Preserving decision-making capacity also critical for managing and implementing a response

Sub-total 71,980,000
Tier 2
Group A
  • Healthy 65 years and older (17.7 million)
  • 6 months to 64 years with 1 high-risk condition (35.8 million)
  • 6-23 months old, healthy (5.6 million)

Rationale: Groups that are also at increased risk but not as high risk as population in Tier 1B

Group B
  • Other public health emergency responders (300,000 = remaining two-thirds of public health work force)
  • Public safety workers including police, fire, 911 dispatchers, and correctional facility staff (2.99 million)
  • Utility workers essential for maintenance of power, water, and sewage system functioning (364,000)
  • Transportation workers transporting fuel, water, food, and medical supplies as well as public ground public transportation (3.8 million)
  • Telecommunications/IT for essential network operations and maintenance (1.08 million); Includes critical infrastructure groups that have impact on maintaining health (e.g., public safety or transportation of medical supplies and food)

Rationale: Implementing a pandemic response; and on maintaining societal functions

Sub-total 67,634,000
Tier 3
  • Other key government health decision-makers (estimated number not yet determined)
  • Funeral directors/embalmers (62,000)

Rationale: Other important societal groups for a pandemic response but of lower priority

Sub-total 62,000+ key government health decision makers
Tier 4
  • Healthy persons 2-64 years not included in above categories (179.3 million)

Rationale: All persons not included in other groups based on objective to vaccinate all those who want protection

Sub-total 179,300,000

Total for all Tiers: 318,967,6000

How limited are antiviral drugs and vaccines expected to be?

Under the best-case scenario, by the end of 2008 the US Government expects there will be 81 million five-day courses of Tamiflu stored in federal and state warehouses available for use. Beginning 6 months after the start of the pandemic, the first 30 million effective doses of a specific pandemic influenza vaccine will be distributed with another 30 million doses rolling out at 6-month intervals until the end of the emergency.

Of course the problem is with this scheme those in the upper tiers will use up most of the Tamiflu and vaccine leaving very little for the majority of people in the lower ones. The US DHHS’ PIP predicts that 90 million people will develop influenza during the coming pandemic be it moderate or severe. I think this is an optimistic estimate and expect that somewhere between 120 and 150 million people in the US will develop the flu during the pandemic.2 If the pandemic is as mild as the government hopes, then 81 million doses might be enough but only if they hew to the standard seasonal flu dose regimen, which uses 10 capsules over 5 days. If instead it becomes obvious that 40 capsules over 10 days if required to get benefit with pandemic flu as many now think, then there will only be 20 million effective does in the stockpile.3 Obviously, this would be an inadequate supply even if the US Government’s sanguine estimate of a clinical attack rate of 90 million proves correct.

Concerns about the rankings used in the current CDC plan

The CDC’s intent under their ration plan is to get the most benefit for society when resources are expected to be scarce during the pandemic. Factors that governed their recommendations include those they considered at highest risk from influenza, healthy people whose work was essential to the flu treatment effort, and lastly how medical costs can be kept under control during the pandemic. The CDC’s pandemic rationing plan began with the plan they use for priority access to seasonal influenza vaccine and then expanded it somewhat by adding in a few groups of healthy people that perform critical tasks needed to keep society functional. While many support this plan as sensible approach, this has not been universal.

Here are a few concerns to consider:

  • Historically during seasonal influenza, the elderly, young children, and adults with chronic medical diseases experience the greatest illness burden. Studies show these groups are at much higher risk from flu complications than young healthy adults during the annual flu season. During the severe 1918 Spanish Influenza, the reverse was true with those aged 15 to 40 having the highest case fatality rates of any group. Given these conditions, does it make sense then to give healthy young adults such a low priority (Tier 4)?
  • During the 1918 Spanish Flu, millions of children worldwide were orphaned by the deaths of both parents. Since this is likely to recur during the coming pandemic, what do you imagine will become of these children in the future? Will they have any chance of reaching the potential they would have had if their parents survived? Who will provide care for these kids after the next pandemic?
  • While all premature deaths are a tragedy, the deaths of a large portion of those aged 15 to 40 as happened in 1918 will have the most profound social and economic cost to the nation. With so many deaths in this key demographic segment, funding of the country’s social safety net will be in jeopardy and remain so for years into the future. It would likely accelerate the financial crisis we all know is coming for both the Medicare and Social Security System by many years.
  • What is the best use of a limited resource during pandemic influenza? Is it the same as during the seasonal flu or not?
  • Who will decide who will get the Tamiflu and vaccine? How will it get to those on the priority list? Who will distribute it? How will they know who is eligible and who is not?
  • Under the current CDC plan, your chronically ill 75-year-old mother (Tier 1, Group B) is allocated one course of Tamiflu intended for her use. Both she and her healthy 14-year-old granddaughter (Tier 4) become severely ill with bird flu. Who gets the medication and who will decide? How will this Hobson’s choice affect the emotional well being of the survivors and deciders?
  • Given the predictable chaos likely to accompany a severe pandemic, how confident can we be that the governmental agencies tasked with the management and distribution of Tamiflu and vaccine will carry out their responsibilities in an efficient and timely manner?
  • Finally, since all medical resources not just antiviral drugs and vaccine will be scarce during the pandemic, is it logical to confine the ration plan to just these two aspects of influenza treatment? It makes little sense to limit the ration plan to a couple of items when the entire healthcare system is at risk of being overwhelmed.
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