WASHINGTON, D.C. -- In accordance with typical seasonal trends, Gallup is beginning to see an increase in the reported incidence of both colds and the flu among American adults, with an average of 1.9% reporting in September that they were "sick with the flu yesterday." This is nearly double the 1.1% found in August but up only slightly from the 1.6% reported at this time last year -- even amid concerns about the potentially widespread impact of H1N1.
While the President's Council of Advisers on Science and Technology estimated in late August that as many as 50% of Americans will contract the so-called swine flu this season (compared to 5% to 20% who get some form of influenza in a typical year), there has not yet been any detectable uptick in self-reported flu incidence relative to the same months in 2008 since the H1N1 outbreak first reached the U.S. in April.
The Gallup-Healthways Well-Being Index surveys a random sample of about 1,000 adults each day, or roughly 30,000 adults a month, on a wide range of topics related to health and wellbeing. One of the daily questions asks, "Were you sick with any of the following yesterday?" The question specifies four illnesses: the flu, a cold, a headache, and allergies.
The reported prevalence of colds is also on the rise, jumping from a daily average of 2.4% of Americans with a cold during August to 5.4% in September.
Measuring colds vs. the flu in a survey research environment is complex due to the overlapping symptoms of the two disease conditions and a lack of understanding about cold vs. flu symptoms on the part of many Americans. In general, the percentage of Americans who report having had a cold the day before the survey is roughly three times the percentage who report having had the flu. Still, the opportunity for year-over-year comparisons, with 2008 data serving as a pre-H1N1 "control group," provides useful insights into the self-reported prevalence of each condition relative to the other, as well as its changes in prevalence from 2008 to 2009. So far, as was the case with the flu, year-over-year comparisons of cold incidence show little variation between the two years since the beginning of the H1N1 outbreak in April.
Incidence of Cold and Flu by Demographic Group (January-June 2009 Results)
Cold and flu incidence differs among a variety of demographic characteristics. In the case of race and ethnicity, for example, the average percentage of Hispanic Americans who on any given day in the first half of 2009 reported having either condition was at least 50% higher than the self-reported rates found among whites, African-Americans/blacks, and Asians. Flu incidence, in particular, is substantially higher within the Hispanic population than within any other racial or ethnic group.
Age, too, relates to the contraction of a cold or the flu among American adults, with 18- to 29-year-olds more than one and a half times as likely as their 65+ counterparts during the first half of 2009 to report having had either condition. People aged 65 and older, however, are at highest risk for complications, hospitalizations, and deaths from influenza. While the Centers for Disease Control and Prevention (CDC) estimate that an average of 36,000 Americans die from influenza each year, the majority of these deaths are found among the elderly.
The January through June 2009 aggregate of data also provides another interesting layer of insight into the potential impact that marital status can have on the probability of catching a cold or the flu. While on any given day in the first half of 2009, fewer than 2% of respondents who are married or widowed said they had the flu, this prevalence climbs by at least a fourth for those who are single or divorced, and more than doubles for those who are currently separated. A daily average of 8.0% of married respondents had a cold, the flu, or both, in the first half of 2009, but this was true of 15.0% of separated respondents, nearly double the rate among those who are married. Widows and widowers are considerably more likely to be over 65 than all other marital status groups, and thus realize the advantage of the older demography of this group in curtailing the contraction of a cold or the flu.
Less pronounced but still statistically significant differences in cold/flu incidences exist between genders, as well as between households with and those without children. Women -- often the primary household caregivers -- are somewhat more likely to report having had the flu or a cold than are men. Respondents of either gender living in households without children are a third less likely on any given day to have the flu and are a fourth less likely to have a cold than are those in households with children.
Gallup will continue to track the self-reported incidence of colds and flu over the coming months to gauge the real-time impact of flu season, and will continue to gauge worry about H1N1.
Survey Methods
Results are based on telephone interviews with 355,334 national adults, aged 18 and older, conducted Jan. 2-Dec. 30, 2008, and 268,204 interviews conducted Jan. 2-Sept. 30, 2009. Monthly samples are near n=30,000 per month. For monthly results based on the total sample of national adults, one can say with 95% confidence that the maximum margin of sampling error is ±0.6 percentage points.
Sample sizes for the reported demographic groups from the first half of 2009 are shown in the accompanying table.
Interviews are conducted with respondents on land-line telephones and cellular phones.
In addition to sampling error, question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of public opinion polls.
About the Gallup-Healthways Well-Being Index™
The Gallup-Healthways Well-Being Index is the first and largest survey of its kind, with 1,000 calls a day, seven days a week. It is the official statistic for Wellbeing in America, giving a daily measure of people's wellbeing at the close of every day based on the World Health Organization (WHO) definition of health as not only the absence of infirmity and disease but also a state of physical, mental and social wellbeing. The Well-Being Index will be a daily measure determining the correlation between the places people work and the communities in which they live, and how that and other factors impact their wellbeing. Additionally, the Well-Being Index will increase the understanding of how those factors impact the financial health of corporations and communities. Learn more about the Gallup-Healthways Well-Being Index.
