2 tables omitted
After the announcement that the supply of inactivated influenza vaccine
available to the U.S. public for the 2004-05 influenza season would be reduced
by approximately one half, the Advisory Committee on Immunization Practices
(ACIP) recommended that the remaining vaccine supply should be reserved for
(1) certain groups of persons at high risk for serious health problems from
influenza, (2) health-care workers involved in direct patient care, and (3)
close contacts of children aged <6 months.1 To determine what
proportion of persons at increased risk for influenza complications had been
vaccinated as of the day of the survey, what proportion sought vaccination
but did not receive it because of the shortage, and what factors might be
dissuading persons at high risk from seeking influenza vaccination, Harvard
School of Public Health (HSPH), in collaboration with International Communications
Research, conducted a national survey. This report summarizes the results
of that survey, which indicated that approximately 63% of persons aged ≥65
years and 46% of chronically ill adults who tried to get the influenza vaccine
were able to do so. More than half of adults at high risk did not try to get
the influenza vaccine. Because available supplies of inactivated influenza
vaccine are targeted to high-risk groups, persons in these groups should continue
to pursue vaccination.
HSPH provides CDC with technical assistance for public health communication
by monitoring the response of the general public to public health threats.
National polling on what the public knows, believes, and experiences in regard
to seeking and receiving influenza vaccination during a national vaccine shortage
is the basis of the data presented in this report.
During October 29–November 9, 2004, telephone interviews were
conducted to assess experiences of respondents with obtaining the influenza
vaccine. The survey was conducted by International Communications Research
as part of an omnibus survey. The omnibus survey is a national, biweekly telephone
survey that can include questions on several topics; however, because of the
length of the questionnaire, the omnibus survey regarding influenza vaccination
only included the HSPH questions. Respondents were asked (1) if they tried
to get the influenza vaccine during the preceding 3 months, (2) if so, whether
they were able to get the vaccine, and (3) whether they experienced any problems
while trying to get the vaccine. Respondents who did not try to get the vaccine
were asked why they did not. Respondents were also asked about their willingness
to receive an imported influenza vaccine not licensed for general use in the
United States. Parents of children aged 6-23 months were asked these questions
about their children in that age group.
The questionnaire was administered to adults aged ≥18 years who were
selected by using a fully replicated, stratified, single-stage, random-digit–dialing
sample of households nationally.* Within each household, an adult respondent
was randomly selected by asking for the adult with the most recent birthday.
A total of 1,227 adults completed interviews. This group included an oversample
of parents with children aged 6-23 months. A total of 249 interviews were
completed with this latter group. Parents were asked vaccine-related questions
about each of their children in the age group.
The data analysis targeted three groups at high risk included among
those prioritized by ACIP for influenza vaccination in 2004: (1) persons aged
≥65 years, (2) persons aged 18-64 years with underlying chronic medical
conditions, and (3) children aged 6-23 months. The data were weighted to account
for the disproportionate probability of household selection attributable to
multiple telephone lines and the probability associated with the random selection
of an individual household member. Following the application of the above
weight, the sample was post-stratified and balanced by age, sex, race/ethnicity,
education, region, census division, and metropolitan status to be nationally
representative. Statistical software was used to calculate standard errors
for weighted data. Confidence intervals (CIs) also were calculated.
Among adult respondents, 242 (19%) were aged ≥65 years; 306 (25%)
had been told by a doctor that they had one of the following health conditions:
heart or lung disease, asthma, kidney disease, diabetes, or a disease that
causes decreased immunity (e.g., cancer or HIV/AIDS). For this analysis, these
groups were combined and referenced as adults at high risk (n = 427), unless
Among adults aged ≥65 years, 119 (49%) tried to get the influenza
vaccine during the preceding 3 months. Among those in this age group who tried
to get the vaccine, 75 (63%) were able to get the vaccine, and 44 (37%) were
unable to do so. A total of 113 (37%) adults with a chronic illness tried
to get the vaccine; among those who tried to get the vaccine, 52 (46%) were
able to get it, whereas 61 (54%) reported being unable to do so..
Respondents were asked to rate problems as either major problems they
experienced when trying to get the vaccine, minor problems, or not problems
at all. The leading problems experienced by the 81 adults at high risk who
tried and could not get the vaccine included the following: (1) no vaccine
was available when they tried to get it (55 [68%] cited this as a major problem)
and (2) finding a place where they could get the vaccine was difficult (41
Among the 427 adults at high risk as defined above, 257 (60%) (CI =
54%-66%) reported that they did not try to get the influenza vaccine during
the preceding 3 months. Awareness of the influenza vaccine shortage was an
important reason cited for not trying to get the vaccine: 82 of these 257
(32%) (CI = 24%-40%) said either that they were waiting until more vaccine
was available or that they believed that, because of shortages, they could
not get the vaccine. Other major reasons included (1) believing that they
were not at high risk for getting a serious case of influenza (53 [21%]; CI
= 14%-27%), (2) not believing that the vaccine would be effective in preventing
them from getting influenza (45 [18%]; CI = 11%-25%), and (3) concerns that
they could get influenza from the vaccine (46 [18%]; CI = 12%-25%).
Of parents with children aged 6-23 months, 125 (50%) (CI = 39%-59%)
tried to get the vaccine for their child; 95 (76%) of those parents who tried
to get the vaccine for their child reported that they were able to get the
influenza vaccine, and 30 (24%) reported that they were unable to do so.
Few problems were reported by parents who tried to get the vaccine.
A total of 14 (11%) (CI = 1%-17%) parents who tried to get the vaccine for
their child reported problems, including (1) difficulty finding vaccine, (2)
inconvenient times, and (3) a health-care provider advising against their
child receiving vaccine because of the shortages or for a medical reason.
For children aged 6-23 months, the leading reasons for not trying to
get inactivated influenza vaccine reported by parents were (1) not believing
their children were at risk for a serious case of influenza (26 [21%]; CI
= 10%-37%); (2) concern about the side effects (24 [19%]; CI = 6%-32%); (3)
being told by a health-care provider that the child should not get the vaccine
because of the shortages and because the child was not at high risk for having
a serious case of influenza (22 [18%]; CI = 7%-34%); and (4) not believing
that the influenza vaccine was effective (16 [13%]; CI = 4%-22%).
To ease the vaccine shortage in the United States, the U.S. government
has announced its intention to import from Germany influenza vaccine not licensed
by the Food and Drug Administration (FDA). The vaccine, Fluarix™ (GlaxoSmithKline,
Dresden, Germany), although fully licensed for use in Germany, is not approved
for general use in the United States and is therefore considered to be investigational.
Respondents were asked if they would be willing to take the vaccine after
being told that the vaccine was investigational. Fifty-six percent (CI = 49%-63%)
of adults at high risk said they would be willing to receive this vaccine
if no other vaccine were available. U.S. persons who elect to receive investigational
vaccines are required to sign a form. With this requirement imposed, willingness
to take the vaccine decreased to 40% (CI = 34%-46%) among adults at high risk.
Reported by: RJ Blendon, ScD, CM DesRoches,
DrPH, JM Benson, MA, KJ Weldon, Harvard School of Public Health, Boston, Massachusetts.
CDC Editorial Note: The findings in this report
suggest that, during the current vaccine shortage, approximately 63% of persons
aged ≥65 years and 46% of chronically ill adults who tried to get the influenza
vaccine were able to do so. However, more than half of adults at high risk
did not try to get the influenza vaccine. For many of these respondents, this
was because of perceived shortages, underscoring the need to continue to encourage
these groups to pursue vaccination. Efforts to vaccinate these groups should
include measures to educate them about the severity of influenza and the effectiveness
of the vaccine and address unwarranted fears of getting influenza from the
vaccine. Finally, the reluctance expressed by adults in priority groups about
receiving imported influenza vaccine not licensed by FDA suggests the need
for educational efforts to provide reassurance that this vaccine is approved
for use in Germany by government agencies similar to the FDA.
In 2004, for the first time, ACIP recommended that children aged 6-23
months be vaccinated. The findings in this report suggest that parents of
children in this age group who tried to get the vaccine for their children
experienced fewer difficulties in getting the vaccine than persons aged ≥65
years or those with chronic illnesses.
The findings in this report are subject to at least two limitations.
First, because the study was conducted as part of an omnibus survey, the data
are not collected in a way that allows for the calculation of the response
rate. However, studies have indicated that when the results from a survey
with a long field period and high response rate are compared with a survey
with a field time that is similar to the HSPH survey, few statistically significant
differences are observed between responses from the two surveys when the data
are statistically reweighted.3-6 Second, the survey sample included
only noninstitutionalized persons. Nursing home residents, who are excluded
from the sample, might receive the influenza vaccine at a different rate than
those in the study sample.
The results of the HSPH survey differ from those of the Behavioral Risk
Factor Surveillance System (BRFSS) survey.2 Important differences
in survey methodologies might contribute to the differences in results. The
primary differences are that (1) the surveys were conducted during different
periods (i.e., October 29–November 9 for HSPH and December 1-11 for
BRFSS); (2) somewhat different questions were asked; and (3) the HSPH data
came from a single, national sample, but BRFSS data were collected individually
by 48 states and the District of Columbia. Despite these differences, both
surveys demonstrate a substantial need for the influenza vaccine that has
not been met.
Assuming that an adequate vaccine supply will be available for persons
in priority groups this season, health-care providers should continue to emphasize
(1) the need for these groups to get vaccinated this season and (2) the availability
of vaccine allowing all persons in these groups to get vaccinated. Influenza
vaccine should continue to be directed to areas most affected by the shortage.
References: 6 available
*Similar questions were asked in the Behavioral Risk Factor Surveillance
System survey reported in this issue of MMWR.2
Experiences With Obtaining Influenza Vaccination Among Persons in Priority Groups During a Vaccine Shortage—United States, October-November, 2004. JAMA. 2005;293(5):544-546. doi:10.1001/jama.293.5.544