Focus for Vaccination Efforts in Oregon Against Pandemic H1N1 Influenza
November 13, 2009


Policy Statement:
Based on Oregon and national data about which groups have been most severely affected by the pandemic H1N1 influenza strain to date, and on projections of a continuing pandemic H1N1 influenza vaccine shortage for at least the next three weeks, the Oregon Public Health Division:

  1. Reaffirms the target groups for vaccination as identified July 29, 2009, by the Advisory Committee on Immunization Practice (ACIP) of the Centers for Disease Control.
  2. Recommends that, in light of the continuing shortage of pandemic H1N1 influenza vaccine, counties and others administering vaccine in Oregon conduct outreach and allocate vaccine in order to help ensure that those in the following sub-groups of the ACIP target groups get vaccinated:
  • Children with certain special health care needs and adults age 5-64 years with chronic medical conditions that put them at risk for complications from influenza infection, as described previously by the ACIP. This includes those with neuro-developmental and other conditions that decrease ability to clear respiratory secretions or increase risk of aspiration.
  • Pregnant women
  • Children under age 5
  • Household contacts and caretakers of infants under 6 months of age
  • Healthcare workers and emergency services personnel

3. Recommends that, where feasible, vaccination should be deferred for those age 5-24 without special health care needs or medical conditions described above. Alternatively, the nasal spray preparation of the vaccine should be used to vaccinate this group of healthy children and young adults.

We anticipate that these recommendations will remain in effect for the next three weeks, pending other changes in vaccine availability or changes in the epidemiology of the pandemic.

These recommendations are summarized in the Table below:

 Age

 Initial Target Groups*

 Focus for special outreach and vaccine allocation decisions

 Any Age

 

 

 household contacts and caregivers for children under 6 months; pregnant women

 yes

 Yes

 healthcare and emergency medical services personnel

 yes

 Yes

 6 mo-4 yrs

yes

Yes

 5-24 yrs

 

 

      with no underlying medical condition

 yes

 No

      with underlying medical condition†

 yes

 Yes

 25-64 yrs

 

 

     with no underlying medical condition

 No

 No

     with underlying medical condition†

 yes

 Yes

 >65 years

 No

 No

 * CDC. Available at www.cdc.gov/mmwr/preview/mmwrhtml/rr5810a1.htm?s_cid=rr5810a1_e
† Includes children and adults with on-going medical disorders involving the lungs, heart, kidneys, blood, liver, or metabolic system (such as diabetes). Also includes those with neuro-developmental or other conditions that can compromise respiratory function or increase the risk of aspiration.

 

 

Background and Rationale:
On July 29, 2009, based on observed incidence of deaths and hospitalized cases to date, the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control (CDC) issued recommendations for use of 2009 H1N1 monovalent influenza vaccine. The recommendations were essentially for universal vaccination of the US population, but given expected delays in producing sufficient vaccine, included “initial target groups”; Oregon state and local public health officials have endorsed this ACIP recommendation.

Data recently released by CDC (http://www.cdc.gov/vaccines/recs/acip/downloads/mtg-slides-oct09/12-2-flu-vac.pdf) indicate that hospitalization rates for H1N1 influenza to date are highest among children <5 years of age, but roughly similar for all older age groups. Pregnant women are about 5 times the risk of hospitalization as others. In addition, most patients hospitalized with influenza have had underlying medical conditions that put them at high risk: 62% of pediatric hospitalizations and 76% of adult hospitalizations reported during April 15 – August 31 had at least one high-risk condition. A recently published review of hospitalizations in California showed similar results (JAMA 2009; 302:1896–902).

National data on laboratory-confirmed deaths from H1N1 to date indicate that the rate of death increases with age, until age 64. Those 50-64 years old had almost twice the rate of death as those 24-49 and those 65 or older. Among a sample of adult deaths studied, 76% had a chronic medical condition. Pregnant women also appear to have approximately a six-fold increased risk of death, compared with the general population.

Data from Oregon show similar over-representation of children with neuro-developmental conditions or other underlying medical conditions and adults with chronic conditions among those hospitalized. We have reviewed charts from a sample of 21 pediatric and 88 adult flu hospitalizations in the Portland metro area, representing about 20% of those hospitalized since September 1. Eighty percent of the children and 83% of the adults in this sample had at least one underlying chronic medical condition. The table below summarizes these findings for the most commonly seen underlying conditions:

Prevalence of Underlying Health Conditions among a Sample of 21 Child and 88 Adult Tri-county Residents Hospitalized with Laboratory-Confirmed Pandemic H1N1 Influenza, September 1, 2009 – November 13, 2009

 

 Hospitalized Children
<18 years old

Prevalence in general
pediatric popualtion

 Hospitalized Adults
>=18 years old

 Prevalence in adult

general population

 Asthma

 33%

 8.4%,Oregon

 33%

 9.9%, Oregon

 COPD

 0

 -

 16%

 10%, US

 Diabetes

 5%

 <1%, Oregon

 23%

 7%, Oregon

 CAD/CVD

 0

 -

 15%

 4%, Oregon

 Morbid Obesity

 0

 -

 8%

 5%, US

 Neuromuscular Disease

 0

 -

 3%

 -

 Neuro-developmental conditions that increase the risk of aspiration

 14%

 6.5%, US

 -

 -

 Pregnant

 0

 -

 17%

 1%, Oregon

Oregon has had five deaths in children to date; of those, four occurred in children with special health needs, including two with cerebral palsy.

As of today Oregon has received approximate 25% of the vaccine needed to vaccinate all of the 1.9 million Oregonians in the initial target group. Although vaccine continues to arrive in Oregon each week, current projections provided by the vaccine manufacturers to CDC suggest that Oregon is unlikely to have received enough vaccine for this entire group until at least January 2010.