Although I don't know the specific numbers, emergency departments have to be one of the primary locations in the United States for administering tetanus toxoid boosters. I have often thought that the CDC guidelines for tetanus booster administration were somewhat strange because to determine if it should be given, it is essential to know whether the patient had the primary immunization series at 2, 4, and 6 months of age. In the ED, who could possibly know that a patient received all of these immunizations when most of those in need of one don't know their immunization status?
We must be doing something right because the number of tetanus cases in the U.S. is very low (generally fewer than 50 per year), and most people who get tetanus are over 40 (70% in one survey), with most having been inadequately or never immunized. Many people believe that a full tetanus immunization series conveys life-long immunity.
But getting back to tetanus boosters in the ED, here's something else intriguing. We tell patients we are giving them a tetanus shot, but not that they're getting a diphtheria booster as well. The U.S. Public Health Service has long advised giving patients both boosters when a tetanus booster is given, based on the belief that diphtheria immunity parallels tetanus immunity. This belief does not acknowledge the assertion by others that tetanus immunity is truly lifelong. In any case, for public health reasons, we sneak a second antigen in when giving a tetanus shot. But this is a little strange. The patient is not advised, there is no true clinical indication for administration of both antigens, and we don't ask permission to give both antigens; we just do it.
Are there potential consequences of giving two antigens when only one is clinically indicated? Apparently. The following study is very old, but indicates that you don't get something for nothing, and that giving two antigens essentially doubles the risk of adverse reactions.
Comparison of the Morbidity of Tetanus Toxoid Boosters with Tetanus Diphtheria Toxoid Boosters
Macko MB, et al
Ann Emerg Med
This random double-blind study compared the incidence of adverse reactions to tetanus toxoid with tetanus-diphtheria toxoid boosters in 193 patients treated at the emergency department of Roger Williams General Hospital in Providence, RI. A follow-up interview was conducted three to five days after administration of tetanus toxoid, adsorbed (93 patients) or tetanus-diphtheria toxoid (100 patients). The patients' subjective assessment of side effects was elicited at the time of follow-up. The two groups were similar in age, interval between injection and follow-up, and nature of injury. Forty-three percent of the patients receiving tetanus toxoid (T) reported no adverse reaction compared with 21 percent of those receiving tetanus-diphtheria toxoid (Td), p<0.001. Pain at the injection site was reported by 48 percent of the patients in the T group, compared with 75 percent of those in the Td group (p<0.001). Local pain that was moderate or severe in nature was reported by 14 percent of the patients in the T group compared with 27 percent of those in the Td group (p<0.05). There were no significant differences between the two groups in the incidence of redness, swelling, itching, or fever.
These results are similar to those reported in an unpublished study conducted in more than 2000 soldiers. Although the incidence of certain subjective side effects was greater following administration of Td boosters, the nature of the side effects was minor. The benefits of the additional protection provided by Td boosters would appear to outweigh the increase in morbidity in susceptible individuals. Because Td boosters are often routinely used in emergency department encounters, an adequate immunization history is important to avoid overtreatment.
New Kid on the Block: Tdap
Now there is a new kid on the block, Tdap: tetanus toxoid with reduced quantities of diphtheria toxoid (just like in the past) and acellular pertussis vaccine. What will be the role of this new vaccine in the ED? Will we adopt the public health approach and sneak in two additional vaccines over and above the tetanus toxoid? And what about the costs? The new vaccine costs about $35 a dose vs. $15 for the old one. Are insurance companies going to be willing to pay the extra $20? And will we be telling patients about the value of getting this second vaccine? It is clear that pertussis exists, and can be a serious problem for young infants. Those advised to get one-time boosters by the American Academy of Pediatrics are adolescents 11 or 12, and catch-up immunizations are advised for those 13 to 18. Although the Boostrix brand of Tdap is approved only for those 10 to 18, the Adacel brand is approved for ages 11 to 64. Should adults be given the option of getting Tdap instead of Td the next time they need a tetanus shot? According to the CDC's Advisory Committee on Immunization Practices guidelines, an adult should be given a one-time dose of Tdap instead of Td if he received his most recent tetanus toxoid 10 or more years prior, but an interval of as little as two years is considered safe if it is anticipated that the individual will be in close contact with infants under a year old. Immunization also is advised for health care workers and day care workers. Based on these recommendations, it would appear that emergency departments may be the primary site for the administration of this vaccine to adults.
The following two papers address the American Academy of Pediatrics guidelines and the more specific issues regarding the safety of immunization with Tdap at intervals shorter than a year after a Td immunization.
Prevention of Pertussis Among Adolescents: Recommendations for Use of Tetanus Toxoid, Reduced Diphtheria Toxoid, and Acellular Pertissus Vaccine
Committee on Infectious Diseases
The authors from the Committee on Infectious Diseases of the American Academy of Pediatrics present an extensive report on their recommendations for adolescent use of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine. Adolescents 11 to 18 (immunity wanes in this age group) should receive a single dose of Tdap (Boostrix [licensed for ages 10–18] or Adacel [licensed for ages 11-64]) instead of Td as a booster if they completed the recommended childhood series of immunizations against these diseases. If both Tdap and tetravalent meningococcal vaccine (Menactral, MCV4) vaccine are indicated, both may be given at the same visit, using separate syringes and different anatomic sites.
Although an interval of at least five years has been suggested between administration of Td and Tdap to limit the risk of severe injection-site reactions, the benefits might exceed the risks of administration at a shorter interval in some circumstances (when the risk of acquiring pertussis or complications of pertussis is increased) and an interval as short as two years was found to be safe in one study. Tdap should be given as an alternative to Td when adolescents not previously immunized with Tdap require tetanus prophylaxis for wound management.
Tdap is not contraindicated in pregnancy, but administration during the second or third trimester is suggested. The safety and immunogenicity of a single Tdap booster also have been demonstrated in persons 19 to 64, but it is not indicated for use in children under 10. This report also provides information on the use of Tdap in adolescents with a history of pertussis or incomplete previous immunization, and contraindications to the use of Tdap.
How Soon After a Prior Tetanus-Diphtheria Vaccination Can One Give Adult Formulation Tetanus-Diphtheria-Acellular Pertussis Vaccine?
Halperin SA, et al
Ped Infect Dis J
BACKGROUND: The increasing incidence of pertussis observed during the past 20 years, principally in adolescents and adults, has been attributed to waning immunity after initial immunization. A tetanus-diphtheria-acellular pertussis (Tdap) vaccine formulation is recommended for use in adolescents and adults, but concerns have been expressed about the possibility of severe injection site reactions (e.g., Arthus-like reactions prompted by a massive inflammatory response related to high preexisting tetanus toxoid antibody levels) if Tdap is given less than 10 years after a prior tetanus-diphtheria (TD or Td) vaccine.
METHODS: The authors from Dalhousie University and Sanofi Pasteur evaluated reactions experienced following administration of Tdap at varying intervals after TD or Td vaccine in 7,150 children and adolescents. Documentation of the timing of previous immunization was available for 7,001 subjects, and adverse event data were available for 5,931 (84.7%).
RESULTS: When compared with the cohort receiving Tdap more than 10 years after prior immunization, Tdap administration from two through nine years after TD or Td was not associated with a significant increase in injection site pain or fever, and no subject developed an Arthus-type reaction or any other major problem. Although injection site erythema and swelling were slightly more common (by about 5% to 10%) in those receiving Tdap less than 10 years after prior immunization, such reactions were not increased in the cohorts with the shortest intervals (2 to 3 years) after administration of Td.
CONCLUSIONS: These findings suggest that Tdap can be safely administered as soon as 18 months after prior TD/Td vaccination.
Antibiotics for Viruses
One of my favorite windmills to tilt relates to using antibiotics for viral illnesses. It's clear to me that American physicians have addicted themselves and their patients to antibiotics. Study after study after study demonstrates the overutilization of antibiotics, although more recent papers suggest we may be doing a little better with the frequency of use, although we are more than making up for it by substituting expensive antibiotics for inexpensive ones.
Here is just the latest such study, and oddly enough, it is published in an emergency medicine journal. What is fascinating is that when prescriptions are matched to ICD-9 diagnoses, many physicians don't feel compelled to make diagnoses that may be traditionally associated with antibiotics. In the current analysis, 38 percent of patients given the diagnosis of URIs were given antibiotics; the doctors didn't even go through the motions of putting down a diagnosis of bronchitis or possible early otitis media or possible, could be, maybe sinusitis. They just out-and-out put down a diagnosis of URI! I have to admire their honesty.
It's discouraging in this analysis that attendings were more than twice as likely to prescribe antibiotics for nonindicated conditions than residents, and usage of inappropriate antibiotics varied tremendously by hospital.
Antibiotic Treatment of Acute Respiratory Infections in Acute Care Settings
Gonzales R, et al
Acad Emerg Med
METHODS: The multicenter Improving Antibiotic Use in Acute Care Treatment project coordinated at the University of Pennsylvania retrospectively examined the use of antibiotics in 2,270 adults with acute respiratory infections who were discharged home after treatment at one of seven VA or seven non-VA emergency departments from November 2003 to February 2004. Diagnoses were categorized as antibiotic-responsive (considered likely to benefit from antibiotics [e.g., pneumonia, sinusitis, pharyngitis, acute exacerbation of chronic bronchitis]) and antibiotic-nonresponsive (rarely or never likely to benefit from antibiotics [e.g., URIs and bronchitis]).
RESULTS: Antibiotic-nonresponsive conditions accounted for 62 percent of the visits, antibiotics were prescribed for 72 percent of the patients with a diagnosis of acute bronchitis, and for 38 percent of those with a diagnosis of URI. The rate of antibiotic prescribing in the series was 63 percent overall, but varied substantially in the individual study sites (42% to 89%). On multivariate analysis, the likelihood of a prescription for antibiotics was influenced by the patients' diagnoses and duration of illness; patients managed by housestaff were significantly less likely to be treated with antibiotics than those managed by attending (adjusted odds ratio, 0.44), largely due to a threefold increase in antibiotic prescribing by attendings for patients with URIs. Factors not associated with antibiotic prescribing included age, sex, race, ethnicity, smoking status, co morbidities, or clinical setting.
CONCLUSIONS: The use of antibiotics for respiratory infections appears to have increased since 1996.