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Tetanus Surveillance --- United States, 1998--2000
F. Brian Pascual, M.P.H.
Emily L. McGinley, M.P.H.
Lynn R. Zanardi, M.D.
Margaret M. Cortese, M.D.
Trudy V. Murphy, M.D. Epidemiology and Surveillance Division
National Immunization Program
Abstract
Problem/Condition: Tetanus is a severe and often fatal infection. The incidence of reported cases in the United States has declined steadily since introduction of tetanus toxoid vaccines in the 1940s.
Reporting Period: This report covers surveillance data for 1998--2000.
Description of System: Physician-diagnosed cases of tetanus were reported to CDC's National Notifiable Disease Surveillance System. Supplemental clinical and epidemiologic information were provided by states.
Results and Interpretation: During 1998--2000, an average of 43 cases of tetanus was reported annually; the average annual incidence was 0.16 cases/million population. The highest average annual incidence of reported tetanus was among persons aged
>60 years (0.35 cases/million population), persons of Hispanic ethnicity
(0.37 cases/million population), and older adults known to have diabetes (0.70 cases/million population). Fifteen percent of the cases were among injection-drug users. The case-fatality ratio was 18% among 113 patients with known outcome; 75% of the deaths were among patients aged
>60 years. No deaths occurred among those who were
up-to-date with tetanus toxoid vaccination. Seventy-three percent of 129 cases with known injury information
available reported an acute injury; of these, only 37% sought medical care for the acute injury, and only 63% of those
eligible received tetanus toxoid for wound prophylaxis.
Interpretation: The majority of tetanus cases occurred among persons inadequately vaccinated or with
unknown vaccination history who sustained an acute injury. Adults aged
>60 years were at highest risk for tetanus and
tetanus-related death.
Public Health Actions: Tetanus is preventable through routine vaccination (i.e., primary series and
decennial boosters) and appropriate management. A shortage of tetanus and diphtheria toxoids vaccine that began during
2000 ended in 2002. Efforts by health-care providers are warranted to vaccinate persons with delayed or
incomplete vaccination, with emphasis on older persons and persons with high-risk conditions.
Introduction
Since the 1940s, the incidence rates of reported cases of tetanus and tetanus-related deaths have decreased steadily
(1). The decrease has been attributed primarily to universal vaccination with tetanus toxoid (i.e., diphtheria and tetanus toxoids and whole-cell pertussis vaccine-pediatric [DTP], diphtheria and tetanus toxoids and acellular pertussis vaccine-pediatric
[DTaP], pediatric diphtheria and tetanus toxoids [DT], and adult tetanus and diphtheria toxoids [Td]). However,
improved wound management and childbirth practices have also contributed to the decrease in reported cases and deaths from tetanus (2--4).
All 50 states have legal requirements that children receive at least a primary series (i.e., 3 doses) of tetanus toxoid
before entering school (5). In 2000, results of the National Immunization Survey indicated that 94% of children aged 19--35 months had received 3 doses of tetanus toxoid
(6). In contrast to the high vaccination rates among young children, the
1998 National Health Interview Survey indicated that only 40% of adults aged >65 years had received a booster dose of
tetanus toxoid during the previous 10 years
(7) as recommended by the Advisory Committee on Immunization Practices (ACIP)
(8). Moreover, only 31% of adults aged >70 years whose serum was tested during 1988--1994 for the Third National Health and Nutrition Examination Survey had protective titers of antibody to tetanus toxin
(9,10).
National surveillance for tetanus is conducted to monitor the trends in disease and the effectiveness of the vaccination program. This report is an analysis of the epidemiology of tetanus in the United States during 1998--2000.
Methods
Tetanus Surveillance
National tetanus surveillance is a passive system that relies on physicians to report cases of tetanus to state and local health departments. Because no laboratory test provides definitive diagnosis of tetanus, the diagnosis of tetanus is based on the clinical judgment of the attending physician. In 1990, the Council of State and Territorial Epidemiologists and CDC adopted a clinical case definition for public health surveillance of tetanus, which is the acute onset of hypertonia and/or painful muscular contractions (usually of the jaw and neck muscles) and generalized muscle spasms without other apparent medical cause (as reported by a health professional)
(11).
State and local health departments report cases of tetanus weekly to the National Notifiable Diseases Surveillance
System (NNDSS). The reports are transmitted to CDC through the National Electronic Telecommunications System for Surveillance (NETSS) and contain supplemental clinical and epidemiologic information for each case. Supplemental
information includes the clinical history; presence and nature of any associated risk factors; the patient's vaccination status, wound care, and clinical management; and outcome for each case of tetanus. CDC contacted state and local health departments for
additional unreported tetanus cases and included 13 cases in this surveillance summary not initially reported to NNDSS.
Data Analysis
For the calculation of rates of reported tetanus cases per million population by demographic variables, the denominator population used was the mid-year resident population
estimates during 1998--2000 (12). For the calculation of rates
of tetanus cases per million persons known to have diabetes by age group, the denominator population represented a weighted estimate of persons known to have diabetes obtained from the 1998--2000 National Health Interview Survey (13--15).
Results
Long-Term Trends in Morbidity and Mortality
The average annual number of tetanus cases during 1998--2000 was 43 --- 45 cases in 1998, 42 in 1999, and 43 in 2000. The lowest average annual number of cases for a 3-year
period in the United States since tetanus became reportable in
1947 was 41 cases per year during 1995--1997
(1). The average annual incidence rate during 1998--2000 was 0.16 cases per
million population, approximately the same as the average annual rate during 1995--1997 (0.15 cases per million population). The incidence rate during 1998--2000 was a 96% decrease from 3.9 cases per million population reported in 1947 (Figure 1). The case-fatality ratio during 1998--2000 was 18% (20 deaths) for 113 patients with known outcome; the case-fatality ratio
was 11% during 1995--1997 (1). The case-fatality ratio during 1998--2000 was 5 times lower than the case-fatality ratio
reported in 1947 (91%).
Epidemiology
During 1998--2000, >1 case of tetanus was reported by 31 states (Figure 2). Six states reported tetanus cases in each of the 3 years (California, Florida, Michigan, Pennsylvania, Texas, and Wisconsin). Nineteen states and the District of
Columbia reported no cases of tetanus. Eight states with no reported cases were in the Rocky Mountain and West North Central
regions, where the incidence of reported tetanus has historically been low
(1,16--20), and no cases of tetanus were reported from
New England (Figure 2).
Age and sex were reported for all 130 cases; race was
reported for 111 (85%) and ethnicity for 123 (95%) of 130
cases. Twelve (9%) of the cases were aged <20 years (including one neonate); 71 (55%) were aged 20--59 years; and 47 (36%) were
aged >60 years (Figure 3). The average annual incidence of tetanus during 1998--2000 was 0.05 cases per million
population among persons aged <20 years, 0.16 cases per million population among adults aged 20--59 years, and 0.35 cases per million population among adults aged >60 years. Seventy-eight cases (60%) were male. The differences in incidence rates between males and females varied by age group. For persons aged <20 years, the incidence of tetanus among males (0.08 cases per million population) was 2.7 times the incidence among females (0.03 cases per million population). For persons aged
20--59 years, the incidence of tetanus among males (0.23 cases per million population) was 2.9 times the incidence among females (0.08 cases per million population). For persons aged
>60 years, the incidence of tetanus was 0.31 cases per
million population among males, lower than the incidence of 0.39 cases per million population among females.
The incidence of tetanus among non-Hispanic whites was 0.13 cases per million population (78 cases); among non-Hispanic blacks, 0.12 cases per million population (12 cases); among Asian/Pacific Islanders, 0.10 cases per million population (three cases); and among Native American/Alaska
Natives, 0.16 cases per million population (one case).
The incidence of reported tetanus among persons with Hispanic ethnicity was 0.38 cases per million population (36 cases) during 1998--2000, compared with 0.27 cases per million during 1995--1997
(1).
The 20 reported deaths occurred among patients aged
33--88 years. Seventy-five percent (15/20) of the patients who
died were aged >60 years. The case-fatality ratio among
patients with known outcome aged >60 years was 40% (15/38), compared with 8% (5/63) among patients with known outcome aged 20--59 years.
Tetanus Toxoid Vaccination
During 1998--2000, the number of doses of tetanus toxoid previously received was reported for 38% (50/130) of
patients, compared with 47% (58/124) during 1995--1997
(1). Eight of 50 patients (16%) with known vaccination history (6% of
all cases) during 1998--2000 had received
>3 doses of tetanus toxoid with the last dose <10 years before the onset of
tetanus (Table 1). All eight patients had nonwork-related acute injuries; six did not seek medical care before the onset of tetanus, and three were aged <20 years.
Twenty patients were reported to have received at least a primary series of tetanus toxoid; 18 had an outcome reported.
Of these 18 patients, one (6%) death occurred; the death was in an injection-drug user (IDU) whose last dose of tetanus toxoid was 11 years before the onset of tetanus. A total of 110 patients reported <3 doses of tetanus toxoid or had an unknown vaccination history; 95 of these patients had an outcome reported. Nineteen deaths (20%) occurred among these 95 patients.
Type of Injury, Wound Treatment, and Prophylaxis
Among 129 patients with information provided on the condition leading to tetanus, acute trauma was reported for
73% (94/129) of patients; no acute injury (i.e., patients with
abscesses, ulcers, or gangrene) was reported for 26% (34/129);
and one case (1%, 1/129) was reported in a neonate
(Table 2). A puncture wound was the most frequent type of acute
trauma (50%), followed by lacerations (33%) and abrasions (9%). Puncture wounds included stepping on a nail (15 cases),
splinter (five cases), injury from barbed wire (five cases), a tattoo (one case), and a spider bite (one case).* The acute injury was located on the lower extremity in 48 (51%) patients, the
upper extremity in 34 (36%) patients, the head or trunk in nine
(10%) patients, and not specified in three patients. The environment in which the acute injury occurred was reported for 83
(88%) patients. Thirty-seven (45%) patients were injured
at home or indoors; 26 (31%) were injured while farming or gardening;
19 (23%) were injured while engaging in other outdoor activities; and one (1%) was injured in an
automobile accident.
Ninety (96%) of the 94 patients with an acute injury had information reported regarding medical care for the injury.
Of these 90 patients, 33 (37%) sought care for the acute
injury. Tetanus toxoid prophylaxis for wound management
was administered to 20 patients (19 of whom were eligible according to ACIP recommendations [21]); no tetanus toxoid
was administered to 12 patients (11 of whom were eligible); and information was not available for one patient. Therefore, 63% (19/30) of eligible patients who sought care received tetanus toxoid prophylaxis.
Clinical Features and Treatment
The median interval between the acute injury reported to have led to tetanus and the onset of tetanus was 7 days (range: 0--112 days) for the 89 nonneonatal patients with a known date of injury. The time between the injury and the onset
of
symptoms was <30 days for 84 (94%) of the patients. Eleven (12%) patients reported an injury
<2 days before the onset of tetanus.
The type of tetanus was reported for 115 patients; 93 (81%) had generalized, 20 (17%) had localized, and two (2%)
had cephalic tetanus. Generalized tetanus was the most common type reported among all age groups. The vaccination history
was known for 40 (43%) patients with generalized tetanus and seven (35%) patients with localized tetanus. Thirteen
(14%) patients with generalized tetanus and five (25%) patients with localized tetanus had received
>3 doses of tetanus toxoid.
Tetanus immune globulin (TIG) was reported to have been given for treatment of tetanus in 125 patients. Time
between reported onset of tetanus and administration of TIG for 121 (97%) patients with information was <24 hours after onset for 32 patients, 1--4 days after onset for 59 patients, and >4 days after onset for 30 patients.
Information regarding hospitalization was reported for 119 (92%) of 130 cases. Of the 115 (97%) hospitalized patients,
the median length of hospitalization was 19 days (range:
1--123 days). Of the 95 patients with information available on
whether or not mechanical ventilation was used, 52 (55%) received mechanical ventilation. Sixteen (31%) of those who required mechanical ventilation died; four (9%) of those who were not mechanically ventilated died.
Neonatal Tetanus
One neonate, delivered in a hospital, developed generalized tetanus on the ninth day of life. The infant had an
infected umbilical cord that had been treated with bentonite clay for cord care at home. TIG therapy was administered within 24 hours of the onset of tetanus, and the baby recovered after 19 days of hospitalization. The baby's U.S.-born mother had
a philosophic objection to vaccination and had received no tetanus toxoid (22).
Tetanus Among Diabetics and IDUs
Diabetic patients constituted 12% (16/130) of the 130
reported cases of tetanus during 1998--2000 (Figure 4),
compared with 2% of cases during 1995--1997
(1). The median age of the diabetic patients during 1998--2000 was 72 years (range:
42--84 years). The average annual incidence rate of tetanus among persons known to have diabetes was 0.26 cases per
million population (four cases) for adults aged 20--59 years and 0.70 cases per million population (12 cases) for adults aged >60 years. Eleven (69%) of the diabetic patients were male; seven (44%) were from Texas; and four (25%) were Hispanic. The vaccination history was reported for two (13%) patients. One patient had received a primary series at an
unknown time before the onset of tetanus, and the other
patient had received a single lifetime dose of tetanus toxoid 4 years before the onset
of tetanus. Eleven of the 16 patients with diabetes had an acute injury; four had gangrene or ulcer; and one had no
wound reported. Only two patients, both with a puncture wound, sought medical attention before the onset of tetanus. Five
(31%) of the 16 patients with diabetes died.
IDUs accounted for 15% (19/130) of the tetanus cases
(Figure 4). The median age of these patients was 41 years (range:
27--57 years); eight patients (42%) were aged 30--39 years. Fifteen (79%) of the patients were male; 16 (84%) were
from California; and 14 (74%) were Hispanic. Of the 19 cases among IDUs reported from all states, 14 (74%) used heroin;
10 (53%) reported injecting black tar heroin, a low-grade resinous form of heroin
(23). The vaccination history was reported
for five (26%) patients. Of these patients, three had received a primary series and a booster dose, with the last dose of tetanus toxoid received either >10 years before the onset of tetanus or at an unknown time before the onset of tetanus; one patient had received a single lifetime dose of tetanus toxoid 9 years before the onset of tetanus, and one
patient had not been vaccinated. Only one patient among the 19 IDUs reported an acute injury. Four (21%) of the 19 IDUs died.
Discussion
Tetanus is an uncommon but severe disease that occurs primarily among persons who are unvaccinated or
inadequately vaccinated. The average annual incidence of tetanus during 1998--2000 was 25% lower than that reported in the late 1980s and 96% lower than that reported in 1947. The age distribution of reported tetanus cases among adults shifted during the late 1990s, primarily because of an overall decrease in the number of cases among older adults, without a substantial reduction in cases among young and middle-aged adults. Persons aged
>60 years accounted for 36% of cases during
1995--2000, compared with 52%--61% of cases during 1982--1994
(1,16--20).
During 1998--2000, the highest rates of tetanus and tetanus-related deaths were among adults aged
>60 years. The immune response to tetanus toxoid can be less robust with increasing age, particularly among adults with chronic conditions
(24,25). A national population-based seroprevalence survey during 1988--1994 indicated that 69% of adults aged >70 years lacked protective levels of tetanus antibody, compared with 9% of children aged 6--11 years
(10). Certain older adults probably missed booster vaccinations, and others might not have received a primary series of tetanus toxoid.
IDUs comprised 15%--18% of the tetanus cases during 1995--2000, compared with 2.1%--4.5% during
1982--1994 (1,16--20). During this period, the majority of the tetanus cases among IDUs was reported among young and
middle-aged adults and accounted for 27% of tetanus patients aged 20--59 years
(1). Injection-drug use has been associated with
an increased risk of tetanus (26--28). The majority of IDUs among the tetanus patients during 1998--2000 had no history of
an acute injury, and a high proportion of patients
reported injection of black-tar heroin. Contaminated drugs, adulterants
(e.g., sugar, quinine, rat poison, laxative, and other illegal drugs), unsanitary injection equipment and practices, and
altered immunity might contribute to an increased risk of tetanus among IDUs
(23,26,28,29). Moreover, the high incidence
of tetanus among Hispanics during 1998--2000 is partly attributable to the cases among IDUs, many of whom were Hispanic.
Vaccination history was known for <60% of tetanus
patients reported from 1982--2000. During 1998--2000, only 6%
of all tetanus patients were known to have been up-to-date with tetanus toxoid vaccination. No deaths occurred among
these vaccinated patients. This finding is consistent with previous reports that illness is less severe among patients who have a history of receiving at least a primary series of tetanus toxoid compared with tetanus among inadequately vaccinated
or unvaccinated patients (2).
Tetanus among children is uncommon in the United States. However, 13 nonneonatal cases occurred among patients
aged <15 years during 1992--2000. Of these, 85% (11/13) were among children whose parents objected to vaccination
(30). Before 1998, the two most recent cases of neonatal tetanus reported in the United States occurred among infants born
in 1989 and in 1995 to immigrant mothers with incomplete tetanus toxoid vaccination
(31,32). The mother of the neonate with tetanus in 1998 was born in the United States but had not received tetanus toxoid because of philosophical objection to vaccination (22). Protection of neonates against tetanus depends on passive transfer of maternal antibody from
vaccinated mothers. Spores of Clostridium
tetani are ubiquitous, and tetanus usually results after contamination of the umbilical cord
(2).
Tetanus contracted after mild injuries or abrasions has previously been recognized and can result when patients do not
seek medical attention or receive appropriate wound management
(1,18--20,33). Among patients with acute injuries and
known medical care history reported from 1998--2000, only 37% sought medical attention for the acute injury; of those who did seek medical attention, only 63% of those eligible received tetanus toxoid as wound prophylaxis. Many of the injuries were probably perceived as mild and occurred in persons inadequately vaccinated.
Surveillance for tetanus has some limitations. Because no confirmatory laboratory test exists, the diagnosis is made
on clinical grounds and with the exclusion of other possible causes of illness. Anaerobic cultures of tissues or aspirates yield C. tetani among only a minority of tetanus patients
(34,35). CDC relies on passive reporting of cases by physicians to state
and local health departments, and no recent evaluation of the completeness of tetanus case reporting to CDC has been
performed. However, the completeness of reporting of tetanus deaths was evaluated in the 1980s
(36). At that time, an estimated 40% of deaths were reported to CDC, and other data indicated that the completeness of reporting of tetanus morbidity might have been even lower. Surveillance for tetanus has remained essentially unchanged,
and the national surveillance system continues to be valuable for identifying and following trends in tetanus disease.
For approximately 50 years, the recommendation that persons receive a primary 3-dose series of tetanus
toxoid-containing vaccine and a booster dose every 10 years has proven to be effective in preventing tetanus or modifying its severity (2). The majority of the tetanus cases during 1998--2000
occurred among persons who were not appropriately
vaccinated against tetanus or who had an unknown vaccination history. Disease-reduction goals for the United States include elimination of tetanus among persons aged <35 years by the year 2010
(37). Although a shortage of tetanus and diphtheria toxoids
vaccine in the United States began in the last quarter of 2000, sufficient supplies of vaccine have been available to resume
routine vaccination since 2002 (38). Health-care providers should evaluate their patients' tetanus vaccination status at each encounter and vaccinate as needed, which is critical among those patients in high-risk groups (e.g., older persons, diabetics,
IDUs, persons with Hispanic ethnicity, pregnant women, persons with philosophical
objections to vaccines, and persons who might not have received a primary series [e.g., immigrants]).
Acknowledgments
The authors acknowledge the contributions of Barbara Bardenheier, M.P.H., M.A., and all reporting state and local health
departments for their efforts in conducting tetanus surveillance.
Gardner P. Issues related to the decennial tetanus-diphtheria toxoid booster recommendations in adults. Infect Dis Clin North Am
2001;15:143--53.
Brauner JS, Rios Vieira SR, Bleck TP. Changes in severe accidental tetanus mortality in the ICU during two decades in Brazil. Intensive Care
Med 2002;28:930--5.
CDC. State immunization requirements, 2001--2002. Atlanta, GA: U.S. Department of Health and Human Services, CDC,
National Immunization Program, 2002. Available at
http://www.immunize.org/laws/izlaws01-02.pdf.
CDC. Percentage of persons aged
>18 years who reported receiving influenza or pneumococcal vaccine or tetanus toxoid, by age and
selected characteristics---National Health Interview Survey, United States, 1998. Available at
http://www.cdc.gov/nip/coverage/nhis/tables/general-98.pdf.
Gergen PJ, McQuillan GM, Kiely M, Ezzati-Rice TM, Sutter RW, Virella G. A population-based serologic survey of immunity to tetanus in
the United States. New Engl J Med 1995;332:761--6.
McQuillan GM, Kruszon-Moran D, Deforest A, Chu SY, Wharton M. Serologic immunity to diphtheria and tetanus in the United States.
Ann Intern Med 2002;136:660--6.
National Center for Health Statistics. National Health Interview Survey, 1998 (machine readable data file and documentation). Hyattsville,
MD: National Health Interview Survey, 2000. Available at ftp://ftp.cdc.gov/pub/health_statistics/nchs/datasets/nhis/1998.
National Center for Health Statistics. National Health Interview Survey, 1999 (machine readable data file and documentation). Hyattsville,
MD: National Health Interview Survey, 2002. Available at ftp://ftp.cdc.gov/pub/health_statistics/nchs/datasets/nhis/1999.
National Center for Health Statistics. National Health Interview Survey, 2000 (machine readable data file and documentation). Hyattsville,
MD: National Health Interview Survey, 2002. Available at ftp://ftp.cdc.gov/pub/health_statistics/nchs/datasets/nhis/2000.
Office of National Drug Control Policy. Pulse check: trends in drug abuse. Washington, D.C.: Executive Office of the President of the
United States, 2001.
Carson PJ, Nichol KL, O'Brien J, Hilo P, Janoff EN. Immune function and vaccine responses in healthy advanced elderly patients. Arch Intern
Med 2000;160:2017--24.
Solomonova K, Vizev S. Secondary response to boostering by purified aluminum-hydroxide-adsorbed tetanus anatoxin in aging and in aged
adults. Immunobiology 1981;158:312--9.
Cherubin CE. Epidemiology of tetanus in narcotic addicts. New York State J Med 1970;70:267--71.
Sangalli M, Chierchini P, Aylward RB, Forastiere F. Tetanus: a rare but preventable cause of mortality among drug users and the elderly. Eur
J Epidemiol 1996;12:539--40.
Rezza G, Pizzuti R, De Campora E, De Masi S, Vlahov D. Tetanus and injections drug use: Rediscovery of a neglected problem? Eur J
Epidemiol 1996;12:655--6.
Sun KO, Chan YW, Cheung RTF, So PC, Yu YL, Li PCK. Management of tetanus: a review of 18 cases. J R Soc Med 1994;87:135--7.
Fair E, Murphy TV, Golaz A, Wharton M. Philosophic objection to vaccination as a risk for tetanus among children younger than 15
years. Pediatrics 2002;109:1--3.
Kumar S, Malecki JM. A case of neonatal tetanus. South Med J 1991;84:396--8.
Craig AS, Reed GW, Mohon RT, et al. Neonatal tetanus in the United States: a sentinel event in the foreign-born. Pediatr Infect Dis J
1997;16:955--9.
Edmondson RS, Flowers MW. Intensive care in tetanus: management, complications, and mortality in 100 cases. Brit Med J 1979;1:1401--4.
Alfery DD, Rauscher LA. Tetanus: a review. Crit Care Med 1979; 7:176--81.
Sutter RW, Cochi SL, Brink EW, Sirotkin BL. Assessment of vital statistics and surveillance data for monitoring tetanus mortality, United
States, 1979--1984. Am J Epidemiol 1990;131:132--42.
US Department of Health and Human Services. Healthy People 2010. 2nd ed. With understanding and improving health and objectives
for improving health. (vol. 1). Washington, D.C.: US Department of Health and Human Services, 2000:14-11-12.
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