Sociodemographic and Geographic Variation in Awareness of Stroke Signs and Symptoms Among Adults — United States, 2017

Weekly / November 6, 2020 / 69(44);1617–1621

Print
Related Pages

Sandra L. Jackson, PhD1; Brian Legvold2; Anjel Vahratian, PhD3; Debra L. Blackwell, PhD3; Jing Fang, MD1; Cathleen Gillespie, MS1; Donald Hayes, MD1; Fleetwood Loustalot, PhD1 (View author affiliations)

View suggested citation

Summary

What is known about this topic?

Awareness of stroke signs and symptoms and the need to call 9-1-1 when those occur can improve stroke outcomes.

What is added by this report?

During 2017, high levels of awareness of individual signs and symptoms of stroke and the need to call 9-1-1 when those occur were reported. However, only two thirds of U.S. adults had the combination of all recommended stroke knowledge, with sociodemographic and geographic variation.

What are the implications for public health practice?

Increasing awareness of the signs and symptoms of stroke continues to be a national priority. Estimates from this report might be used to inform communication strategies that improve awareness and reduce disparities.

Article Metrics
Altmetric:
Citations:
Views:

Views equals page views plus PDF downloads

Metric Details
Tables

Table 1

Table 2

Related Materials

Stroke is the fifth leading cause of death in the United States (1). In 2017, on average, a stroke-related death occurred every 3 minutes and 35 seconds in the United States, and stroke is a leading cause of long-term disability (1). To prevent mortality or long-term disability, strokes require rapid recognition and early medical intervention (2,3). Common stroke signs and symptoms include sudden numbness or weakness of the face, arm, or leg, especially on one side; sudden confusion or trouble speaking; sudden trouble seeing in one or both eyes; sudden trouble walking, dizziness, or loss of balance; and a sudden severe headache with no known cause. Recommended action at the first sign of a suspected stroke is to quickly request emergency services (i.e., calling 9-1-1) (2). Public education campaigns have emphasized recognizing stroke signs and symptoms and the importance of calling 9-1-1, and stroke knowledge increased 14.7 percentage points from 2009 to 2014 (4). However, disparities in stroke awareness have been reported (4,5). Knowledge of the five signs and symptoms of stroke and the immediate need to call emergency medical services (9-1-1), collectively referred to as “recommended stroke knowledge,” was assessed among 26,076 adults aged ≥20 years as part of the 2017 National Health Interview Survey (NHIS). The prevalence of recommended stroke knowledge among U.S. adults was 67.5%. Stroke knowledge differed significantly by race and Hispanic origin (p<0.001). The prevalence of recommended stroke knowledge was highest among non-Hispanic White adults (71.3%), followed by non-Hispanic Black adults (64.0%) and Hispanic adults (57.8%). Stroke knowledge also differed significantly by sex, age, education, and urbanicity. After multivariable adjustment, these differences remained significant. Increasing awareness of the signs and symptoms of stroke continues to be a national priority. Estimates from this report can inform public health strategies for increasing awareness of stroke signs and symptoms.

NHIS is an annual survey of the civilian noninstitutionalized U.S. population. In 2017, NHIS included supplemental content in the sample adult interview that provided a list of five signs and symptoms and asked respondents to identify whether each was a symptom “that someone may be having a stroke.” Respondents also were asked to choose “the best thing to do right away” if “you thought someone was having a stroke.” One choice was to call 9-1-1.*

The prevalence of knowing each of the five signs and symptoms, to call 9-1-1 for a suspected stroke, and the combination of recommended stroke knowledge was estimated overall and by subgroup. Point estimates and corresponding variances were calculated using SAS-callable SUDAAN (version 11.0; RTI International), accounting for the complex sample design, and weighted to be nationally representative. Satterthwaite-adjusted chi-squared tests were used to assess significant (p<0.05) bivariate associations. Logistic regression models (including age, sex, race/ethnicity, education, county urbanicity [large metropolitan area, medium or small metropolitan area, and rural], and region [Northeast, Midwest, South, and West]) were used to generate adjusted prevalence ratios and 95% confidence intervals.

A majority of U.S. adults identified each of the individual signs and symptoms of stroke (Table 1). Prevalence was highest for “numbness of face, arm, leg, or side” (94.4%), “confusion or trouble speaking” (93.6%), and “trouble walking” (90.8%). “Sudden trouble seeing” was identified by 83.5%, and “sudden severe headache” by 76.5%. Awareness of calling 9-1-1 was high (96.3%). Prevalence of recommended stroke knowledge was 67.5%.

Awareness of individual signs and symptoms of stroke and recommended stroke knowledge differed significantly among subgroups (Table 1). The percentage of adults with recommended stroke knowledge ranged from 57.8% among Hispanic adults to 71.3% among non-Hispanic White adults and from 54.8% among adults with less than a high school education to 73.1% among college graduates. After multivariable adjustment, disparities in recommended stroke knowledge persisted by race and Hispanic origin and by education status. Smaller differences in the prevalence of recommended stroke knowledge were noted by sex, age, urbanicity, and region (Table 2).

Top

Discussion

Increasing awareness of signs and symptoms of stroke and the need to call 9-1-1 is vital to enable patients to quickly initiate stroke care and benefit from advances in treatment and systems of care (6,7). Although knowledge of most signs and symptoms of stroke, and for calling 9-1-1, were high, gaps in knowledge remain. Knowledge varied across geographic and sociodemographic subgroups. Consistent with overall prevalence reported for 2014 (66.2%) (4), approximately two thirds (67.5%) of U.S. adult respondents could identify the combination of recommended stroke knowledge in 2017.

Delays in recognizing stroke signs and symptoms might slow initiation of care. The symptom “sudden severe headache” had the lowest prevalence of awareness. This might be an artifact of its position in the survey questionnaire (the last listed symptom), or because headache is a symptom common to many conditions. Current stroke symptom awareness campaigns might inconsistently emphasize headache; some educational campaigns use incomplete acronyms, such as BE-FAST (balance, eyes, face, arms, speech, time), which does not reference headache.

The Healthy People 2020 goal for awareness of common stroke signs and symptoms (HDS-17) is 59.3% and for calling 9-1-1 is 94.7% (age-adjusted, using NHIS) (8). The weighted, but not age-adjusted, prevalence estimates reported here indicate that nationally and regionally, these targets might have been exceeded. However, consistent with previous work, this report demonstrates that awareness varies among some demographic groups (4,5). For example, multivariable results indicated that awareness of stroke signs and symptoms decreased with decreasing education. In addition, awareness was less prevalent among other race and Hispanic origin groups than among non-Hispanic White adults.

Previous studies have shown that stroke morbidity and mortality vary across populations and communities and disproportionately affect racial and ethnic minorities, persons with less education, and persons living in the Southeast (i.e., the “stroke belt”) (1). Among some subgroups, stroke mortality might be increasing, and overall, declines in stroke death rates have stalled in most states (9). The extent to which an increase in stroke knowledge could affect existing disparities and trends in stroke mortality is unknown.

Improvements in stroke outcomes depend on early recognition and timely initiation of care, as well as medical advances and care coordination. CDC’s Paul Coverdell National Acute Stroke Program† aims to improve the continuum of care, including emergency services activation. In addition, the U.S. Department of Health and Human Services’ Million Hearts§ initiative aims to prevent 1 million heart attacks and strokes by 2022 through targeted community and health system interventions. The Get With The Guidelines-Stroke program of the American Heart Association and the American Stroke Association has supported improvements in care, including evidence-based interventions such as tissue plasminogen activator (tPA) (10). Rapid recognition of stroke signs and symptoms and then immediately calling 9-1-1 increases the potential for ischemic stroke patients to quickly receive tPA, maximizing the health benefit.

The findings in this report are subject to at least five limitations. First, all data were self-reported and subject to recall and social desirability biases. Second, questions did not capture all potential stroke signs and symptoms. Third, close-ended (yes/no) questions might overestimate awareness. Fourth, no established standard is available for determining stroke awareness or how knowledge translates into appropriate action in response to a stroke, overall or across subgroups. Finally, the sample size was large, enabling detection of slight statistical differences, but no clear threshold exists for classifying meaningful differences in stroke knowledge to prompt earlier recognition and more timely care.

Primary prevention is central to promoting cardiovascular health and includes assessment and management of stroke risk factors (7). When strokes do occur, recognition of signs and symptoms and then calling 9–1-1 are needed to initiate care quickly to improve outcomes. This report identified overall high awareness of individual signs and symptoms, yet observed lower awareness for certain symptoms. Only approximately two thirds of adults surveyed had the combination of recommended stroke knowledge, and geographic variation and sociodemographic disparities remain. Focused public health efforts, community engagement, innovative strategies to tailor messaging, and continued advances in clinical care and coordination might help address stalled declines in stroke mortality (9). Increasing awareness of the signs and symptoms of stroke continues to be a national priority (6), and estimates from this report might be used to inform communication strategies.

Top

Corresponding author: Sandra Jackson, SLJackson@cdc.gov, 770-488-4221.

Top

1Division for Heart Disease and Stroke Prevention, National Center for Chronic Disease Prevention and Health Promotion, CDC; 2Rollins School of Public Health, Department of Epidemiology, Emory University, Atlanta, Georgia; 3Division of Health Interview Statistics, National Center for Health Statistics, CDC.

Top

All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

Top


* The choices included “advise them to drive to the hospital,” “advise them to call their physician,” “call 9-1-1 (or another emergency number),” “call spouse or family member,” and “other.”

† https://www.cdc.gov/dhdsp/programs/stroke_registry.htm.

§ https://millionhearts.hhs.gov/.

https://www.heart.org/en/professional/quality-improvement/get-with-the-guidelines/get-with-the-guidelines-stroke.

Top

References

  1. Virani SS, Alonso A, Benjamin EJ, et al.; American Heart Association Council on Epidemiology and Prevention Statistics Committee and Stroke Statistics Subcommittee. Heart disease and stroke statistics—2020 update: a report from the American Heart Association. Circulation 2020;141:e139–596. CrossRef PubMed
  2. Powers WJ, Rabinstein AA, Ackerson T, et al.; American Heart Association Stroke Council. 2018 Guidelines for the early management of patients with acute ischemic stroke: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke 2018;49:e46–110. CrossRef PubMed
  3. Fonarow GC, Zhao X, Smith EE, et al. Door-to-needle times for tissue plasminogen activator administration and clinical outcomes in acute ischemic stroke before and after a quality improvement initiative. JAMA 2014;311:1632–40. CrossRef PubMed
  4. Patel A, Fang J, Gillespie C, et al. Awareness of stroke signs and symptoms and calling 9-1-1 among US adults: National Health Interview Survey, 2009 and 2014. Prev Chronic Dis 2019;16:180564. CrossRef PubMed
  5. Ojike N, Ravenell J, Seixas A, et al. Racial disparity in stroke awareness in the US: an analysis of the 2014 National Health Interview Survey. J Neurol Neurophysiol 2016;7:365. CrossRef PubMed
  6. Higashida R, Alberts MJ, Alexander DN, et al.; American Heart Association Advocacy Coordinating Committee. Interactions within stroke systems of care: a policy statement from the American Heart Association/American Stroke Association. Stroke 2013;44:2961–84. CrossRef PubMed
  7. Adeoye O, Nyström KV, Yavagal DR, et al. Recommendations for the establishment of stroke systems of care: a 2019 update. Stroke 2019;50:e187–210. CrossRef PubMed
  8. US Department of Health and Human Services. Healthy people 2020: heart disease and stroke. Washington, DC: US Department of Health and Human Services; 2014. https://www.healthypeople.gov/2020/topics-objectives/topic/heart-disease-and-stroke/objectives
  9. Yang Q, Tong X, Schieb L, et al. Vital signs: recent trends in stroke death rates—United States, 2000–2015. MMWR Morb Mortal Wkly Rep 2017;66:933–9. CrossRef PubMed
  10. Howard G, Schwamm LH, Donnelly JP, et al. Participation in Get With The Guidelines–Stroke and its association with quality of care for stroke. JAMA Neurol 2018;75:1331–7. CrossRef PubMed

Top

TABLE 1. Percentages (and standard errors)* of adults aged ≥20 years who knew stroke signs and symptoms and appropriate action to take in the event of a stroke, by sociodemographic and geographic characteristics — National Health Interview Survey, United States, 2017Return to your place in the text
Characteristic % (Standard error)
Face, arm, leg, side numbness Confusion, trouble speaking Sudden trouble seeing Trouble walking Sudden severe headache Knows all five stroke signs and symptoms Knows to call 9-1-1 Knows all five signs and symptoms and to call 9-1-1§
Total 94.4 (0.22) 93.6 (0.25) 83.5 (0.34) 90.8 (0.26) 76.5 (0.37) 69.1 (0.42) 96.3 (0.16) 67.5 (0.43)
Sex
Men 93.7 (0.32) 93.0 (0.36) 83.0 (0.48) 90.1 (0.38) 74.3 (0.53) 67.0 (0.60) 96.0 (0.23) 65.3 (0.60)
Women 95.0 (0.25) 94.2 (0.29) 83.9 (0.42) 91.4 (0.33) 78.6 (0.46) 71.2 (0.52) 96.6 (0.21) 69.6 (0.53)
p-value† <0.001 0.005 0.123 0.006 <0.001 <0.001 0.039 <0.001
Age group (yrs)
20–44 94.4 (0.32) 93.3 (0.39) 84.1 (0.53) 90.3 (0.40) 74.4 (0.57) 67.2 (0.63) 96.9 (0.24) 65.9 (0.63)
45–64 94.8 (0.35) 94.4 (0.35) 84.9 (0.47) 91.6 (0.40) 78.4 (0.57) 71.3 (0.64) 96.5 (0.25) 69.8 (0.65)
≥65 93.6 (0.37) 93.0 (0.38) 80.0 (0.62) 90.3 (0.45) 77.9 (0.66) 69.6 (0.71) 94.9 (0.33) 67.3 (0.74)
p-value 0.087 0.01 <0.001 0.02 <0.001 <0.001 <0.001 <0.001
Race and Hispanic origin
White, non-Hispanic 96.6 (0.20) 96.5 (0.22) 86.8 (0.34) 93.5 (0.27) 79.0 (0.42) 73.0 (0.47) 96.7 (0.19) 71.3 (0.49)
Black, non-Hispanic 93.0 (0.74) 91.7 (0.90) 81.2 (1.12) 88.6 (0.84) 74.4 (1.18) 65.0 (1.33) 97.1 (0.40) 64.0 (1.34)
Other, non-Hispanic 91.1 (0.79) 88.6 (0.94) 78.5 (1.25) 87.8 (0.94) 71.6 (1.27) 63.5 (1.47) 94.7 (0.71) 61.9 (1.45)
Hispanic 88.0 (0.70) 86.0 (0.80) 74.2 (1.06) 82.7 (0.87) 70.7 (1.12) 59.6 (1.23) 95.2 (0.46) 57.8 (1.25)
p-value <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001
Level of education
Less than HS 85.3 (0.94) 82.7 (1.17) 70.3 (1.31) 80.2 (1.06) 67.9 (1.18) 56.7 (1.33) 93.5 (0.59) 54.8 (1.36)
HS or GED 92.9 (0.47) 92.4 (0.45) 79.8 (0.65) 88.7 (0.54) 74.4 (0.71) 65.1 (0.79) 96.0 (0.32) 63.4 (0.81)
Some college 96.3 (0.29) 95.7 (0.36) 85.9 (0.52) 93.2 (0.40) 78.1 (0.62) 71.1 (0.67) 96.9 (0.25) 69.4 (0.68)
College graduate 96.7 (0.23) 96.4 (0.25) 88.4 (0.43) 93.8 (0.34) 79.8 (0.54) 74.5 (0.62) 97.1 (0.22) 73.1 (0.61)
p-value <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001
County urbanicity
Large metropolitan counties 93.7 (0.27) 92.7 (0.34) 82.7 (0.43) 89.8 (0.34) 75.2 (0.49) 67.8 (0.54) 96.2 (0.22) 66.1 (0.54)
Medium or small metropolitan counties 95.6 (0.32) 95.2 (0.35) 85.1 (0.59) 92.4 (0.41) 79.2 (0.62) 71.4 (0.78) 96.7 (0.28) 69.9 (0.80)
Rural counties 94.8 (0.84) 94.1 (0.84) 83.2 (1.10) 91.3 (0.93) 76.4 (1.24) 70.2 (1.31) 96.0 (0.47) 68.3 (1.38)
p-value 0.004 <0.001 0.014 <0.001 <0.001 0.002 0.23 0.001
Region
Northeast 94.9 (0.45) 93.4 (0.55) 83.9 (0.70) 90.2 (0.63) 77.6 (0.91) 70.4 (0.90) 96.3 (0.40) 69.0 (0.90)
Midwest 95.9 (0.33) 95.8 (0.31) 84.9 (0.63) 92.6 (0.48) 75.2 (0.67) 68.5 (0.79) 97.0 (0.30) 67.1 (0.84)
South 93.5 (0.43) 92.7 (0.53) 83.2 (0.60) 90.4 (0.46) 77.3 (0.65) 69.7 (0.75) 96.2 (0.27) 68.0 (0.77)
West 93.9 (0.41) 93.3 (0.45) 82.3 (0.73) 90.1 (0.53) 75.8 (0.80) 67.8 (0.93) 96.0 (0.36) 66.0 (0.92)
p-value <0.001 <0.001 0.057 0.001 0.088 <0.001 0.153 0.123
Unweighted sample size 26,076 26,076 26,076 26,076 26,076 26,074 26,076 26,073

Abbreviations: GED = general educational development; HS = high school.
* Weighted percentages. “Don’t know” responses are treated as “no”; “not ascertained and refused” responses are converted to blanks and are not included in the numerators or denominators.
† P-values calculated from Satterthwaite-adjusted chi-squared tests.
§ The combination of knowing all five signs and symptoms of stroke and to call 9-1-1 is referred to as “recommended stroke knowledge.”
Education was missing for 91 adults in the sample; these participants were omitted when education was assessed.

Top

TABLE 2. Adjusted prevalence ratios (and 95% CI)* of knowledge of stroke signs and symptoms and appropriate action to take in the event of a stroke, among adults aged ≥20 years — National Health Interview Survey, United States, 2017Return to your place in the text
Characteristic Prevalence ratio (95% CI)
Face, arm, leg, side numbness Confusion, trouble speaking Sudden trouble seeing Trouble walking Sudden severe headache Knows all five stroke signs and symptoms Knows to call 9-1-1 Knows all five signs and symptoms and to call 9-1-1†
Sex
Men versus women 0.99 (0.98–0.99) 0.99 (0.98–0.99) 0.99 (0.97–1.00) 0.99 (0.98–1.00) 0.95 (0.93–0.96) 0.94 (0.92–0.96) 0.99 (0.99–1.00) 0.94 (0.92–0.96)
Age group (yrs)
20–44 versus ≥65 1.02 (1.00–1.03) 1.01 (1.00–1.02) 1.06 (1.04–1.08) 1.01 (0.99–1.02) 0.96 (0.94–0.98) 0.98 (0.96–1.01) 1.02 (1.01–1.03) 0.99 (0.97–1.02)
45–64 versus ≥65 1.02 (1.01–1.03) 1.02 (1.01–1.03) 1.07 (1.05–1.09) 1.02 (1.01–1.03) 1.01 (0.99–1.03) 1.03 (1.01–1.06) 1.02 (1.01–1.03) 1.04 (1.02–1.07)
Race and Hispanic origin
Hispanic versus White, non-Hispanic 0.94 (0.93–0.95) 0.93 (0.91–0.94) 0.89 (0.87–0.92) 0.92 (0.91–0.94) 0.94 (0.91–0.97) 0.88 (0.84–0.91) 0.99 (0.98–1.00) 0.87 (0.83–0.91)
Black versus White, non-Hispanic 0.98 (0.96–0.99) 0.97 (0.95–0.98) 0.95 (0.92–0.97) 0.96 (0.94–0.98) 0.96 (0.92–0.99) 0.91 (0.88–0.95) 1.01 (1.00–1.02) 0.92 (0.88–0.96)
Other versus White, non-Hispanic 0.94 (0.92–0.96) 0.92 (0.90–0.94) 0.90 (0.87–0.93) 0.94 (0.92–0.96) 0.91 (0.88–0.95) 0.87 (0.83–0.91) 0.98 (0.96–0.99) 0.87 (0.83–0.91)
Level of education§
Less than HS versus college degree 0.92 (0.90–0.93) 0.90 (0.88–0.92) 0.84 (0.81–0.87) 0.89 (0.87–0.91) 0.86 (0.83–0.89) 0.79 (0.75–0.83) 0.97 (0.96–0.98) 0.78 (0.74–0.82)
HS or GED versus college degree 0.96 (0.95–0.97) 0.96 (0.95–0.97) 0.91 (0.89–0.93) 0.95 (0.94–0.96) 0.93 (0.91–0.95) 0.88 (0.85–0.90) 0.99 (0.98–1.00) 0.87 (0.84–0.90)
Some college versus college degree 1.00 (0.99–1.00) 0.99 (0.99–1.00) 0.97 (0.96–0.99) 1.00 (0.98–1.01) 0.98 (0.96–1.00) 0.96 (0.93–0.98) 1.00 (0.99–1.00) 0.95 (0.93–0.97)
County urbanicity
Rural versus large metropolitan 1.01 (0.99–1.03) 1.01 (0.99–1.03) 1.01 (0.98–1.03) 1.01 (0.99–1.03) 1.02 (0.99–1.05) 1.04 (1.00–1.08) 1.00 (0.99–1.01) 1.04 (1.00–1.08)
Medium or small metropolitan versus large metropolitan 1.02 (1.01–1.03) 1.02 (1.01–1.03) 1.02 (1.01–1.04) 1.02 (1.01–1.03) 1.05 (1.03–1.07) 1.05 (1.02–1.08) 1.01 (1.00–1.01) 1.05 (1.02–1.08)
Region
Northeast versus Midwest 1.00 (0.99–1.01) 0.99 (0.97–1.00) 1.00 (0.98–1.03) 0.98 (0.97–1.00) 1.04 (1.01–1.07) 1.05 (1.01–1.09) 1.00 (0.99–1.01) 1.05 (1.01–1.09)
South versus Midwest 0.99 (0.98–1.00) 0.98 (0.97–1.00) 1.01 (0.99–1.03) 0.99 (0.98–1.01) 1.05 (1.02–1.07) 1.05 (1.02–1.09) 0.99 (0.99–1.00) 1.05 (1.02–1.08)
West versus Midwest 1.00 (0.99–1.01) 1.00 (0.99–1.01) 1.01 (0.98–1.03) 1.00 (0.98–1.01) 1.04 (1.01–1.07) 1.04 (1.00–1.08) 0.99 (0.99–1.00) 1.03 (1.00–1.07)
Unweighted sample size 25,985 25,985 25,985 25,985 25,985 25,983 25,985 25,982

Abbreviations: CI = confidence interval; GED = general educational development; HS = high school.
* Models included sex, age, race and Hispanic origin, education, county urbanicity, and region. “Don’t know” responses on knowing the signs and symptoms of stroke were treated as no; all not ascertained and refused responses were treated as missing and excluded from these analyses.
† The combination of knowing all five signs and symptoms of stroke and to call 9-1-1 is referred to as “recommended stroke knowledge.”
§ Education was missing for 91 adults in the sample; these participants were omitted when education was assessed.

Top


Suggested citation for this article: Jackson SL, Legvold B, Vahratian A, et al. Sociodemographic and Geographic Variation in Awareness of Stroke Signs and Symptoms Among Adults — United States, 2017. MMWR Morb Mortal Wkly Rep 2020;69:1617–1621. DOI: http://dx.doi.org/10.15585/mmwr.mm6944a1.

MMWR and Morbidity and Mortality Weekly Report are service marks of the U.S. Department of Health and Human Services.
Use of trade names and commercial sources is for identification only and does not imply endorsement by the U.S. Department of Health and Human Services.
References to non-CDC sites on the Internet are provided as a service to MMWR readers and do not constitute or imply endorsement of these organizations or their programs by CDC or the U.S. Department of Health and Human Services. CDC is not responsible for the content of pages found at these sites. URL addresses listed in MMWR were current as of the date of publication.

All HTML versions of MMWR articles are generated from final proofs through an automated process. This conversion might result in character translation or format errors in the HTML version. Users are referred to the electronic PDF version (https://www.cdc.gov/mmwr) and/or the original MMWR paper copy for printable versions of official text, figures, and tables.

Questions or messages regarding errors in formatting should be addressed to mmwrq@cdc.gov.

View Page In: PDF [162K]