Risk of medically attended local reactions following diphtheria toxoid containing vaccines in adolescents and young adults: a Vaccine Safety Datalink study

Real-world evidence of quadrivalent meningococcal conjugate vaccine safety in the United States: a systematic review

Two quadrivalent meningococcal conjugate vaccines (MenACWY) that prevent invasive meningococcal disease caused by N. meningitidis serogroups A, C, Y, and W have been licensed in the U.S. in the past 10-15 years. We systematically reviewed published studies conducted in the U.S. to evaluate the real-world safety evidence of meningococcal conjugate vaccines. We performed a literature search in PubMed of publications from 01/01/2005 to 02/29/2020 and identified 18 studies meeting inclusion criteria. Populations included high-risk persons aged 2 months to 10 years, adolescents/adults aged ≥11 years, pregnant populations, and hematopoietic cell transplant recipients. We extracted information about study setting, study design, exposure, outcomes, comparison group, follow-up/look back period, study population, sample size, available demographic/indication information, results, key conclusion, and reference. These published studies found no new significant safety concerns related to MenACWY. Consideration for future research includes a post-licensure safety evaluation of a new MenACWY product approved in April 2020.

Meningococcal Vaccination: Recommendations of the Advisory Committee on Immunization Practices, United States, 2020

This report compiles and summarizes all recommendations from CDC's Advisory Committee on Immunization Practices (ACIP) for use of meningococcal vaccines in the United States. As a comprehensive summary and update of previously published recommendations, it replaces all previously published reports and policy notes. This report also contains new recommendations for administration of booster doses of serogroup B meningococcal (MenB) vaccine for persons at increased risk for serogroup B meningococcal disease. These guidelines will be updated as needed on the basis of availability of new data or licensure of new meningococcal vaccines. ACIP recommends routine vaccination with a quadrivalent meningococcal conjugate vaccine (MenACWY) for adolescents aged 11 or 12 years, with a booster dose at age 16 years. ACIP also recommends routine vaccination with MenACWY for persons aged ≥2 months at increased risk for meningococcal disease caused by serogroups A, C, W, or Y, including persons who have persistent complement component deficiencies; persons receiving a complement inhibitor (e.g., eculizumab [Soliris] or ravulizumab [Ultomiris]); persons who have anatomic or functional asplenia; persons with human immunodeficiency virus infection; microbiologists routinely exposed to isolates of Neisseria meningitidis; persons identified to be at increased risk because of a meningococcal disease outbreak caused by serogroups A, C, W, or Y; persons who travel to or live in areas in which meningococcal disease is hyperendemic or epidemic; unvaccinated or incompletely vaccinated first-year college students living in residence halls; and military recruits. ACIP recommends MenACWY booster doses for previously vaccinated persons who become or remain at increased risk.In addition, ACIP recommends routine use of MenB vaccine series among persons aged ≥10 years who are at increased risk for serogroup B meningococcal disease, including persons who have persistent complement component deficiencies; persons receiving a complement inhibitor; persons who have anatomic or functional asplenia; microbiologists who are routinely exposed to isolates of N. meningitidis; and persons identified to be at increased risk because of a meningococcal disease outbreak caused by serogroup B. ACIP recommends MenB booster doses for previously vaccinated persons who become or remain at increased risk. In addition, ACIP recommends a MenB series for adolescents and young adults aged 16-23 years on the basis of shared clinical decision-making to provide short-term protection against disease caused by most strains of serogroup B N. meningitidis.

Adverse events following quadrivalent meningococcal diphtheria toxoid conjugate vaccine (Menactra®) reported to the Vaccine Adverse Event Reporting System (VAERS), 2005-2016

BACKGROUND

Post marketing safety evaluations of quadrivalent meningococcal diphtheria-toxoid conjugate vaccine (MenACWY-D) have focused on post-vaccination risk of Guillain Barré syndrome (GBS), adverse events (AEs) after maternal vaccination, and comparative studies with the newer quadrivalent meningococcal CRM197 conjugate vaccine (MenACWY-CRM). To provide an updated general safety assessment, we reviewed reports of AEs following MenACWY-D submitted to the Vaccine Adverse Event Reporting System (VAERS).

METHODS

VAERS is a national spontaneous reporting vaccine safety surveillance system co-administered by the Centers for Disease Control and Prevention and the U.S. Food and Drug Administration. We searched the VAERS database for U.S. reports of AEs after administration of MenACWY-D from January 2005 through June 2016. We conducted clinical reviews of serious reports after MenACWY-D administered alone, reports of MenACWY-D use during pregnancy, and reports of selected pre-specified outcomes. We screened for disproportionate reporting of AEs after MenACWY-D using empirical Bayesian data mining.

RESULTS

VAERS received 13,075 U.S. reports after receipt of MenACWY-D; most (86%) described vaccination in adolescents, were classified as non-serious (94%), and described AEs consistent with pre-licensure studies. We did not find any evidence that reported deaths were related to vaccination. In serious reports, GBS and meningococcal infection were the most commonly reported medical conditions. Many reports of MenACWY-D use during pregnancy described inadvertent vaccination; most (61%) did not report any AE.

CONCLUSIONS

Findings from our comprehensive review of reports to VAERS following MenACWY-D are consistent with data from pre-licensure studies and provide further reassurance on the safety of MenACWY-D.

Arthus Reaction as an Adverse Event Following Tdap Vaccination

Repeat administration of tetanus toxoid-containing vaccines has rarely been associated with Arthus phenomenon, an immune-complex reaction. In the US, since 2013, tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccines (Tdap) have been recommended for administration during each pregnancy. Separately, in 2019, one Tdap was approved for repeat administration in adults in the US. We aimed to describe trends in spontaneously reported Arthus reactions following Tdap in the US and to assess the risk of this phenomenon in persons receiving Tdap repeatedly. We reviewed Arthus reports in the Vaccine Adverse Events Reporting System (VAERS), 1990-2018. Reporting rates were estimated using Tdap doses distributed data. A systematic literature review was conducted in MEDLINE for any Arthus cases reported in Tdap clinical trials and observational studies published between 2000 and 2019. We found 192 Arthus reports in VAERS after any vaccine, of which 36 occurred after Tdap and none were reported during pregnancy. The Arthus reporting rate was estimated at 0.1 per million doses distributed. We identified eight published studies of Tdap administration within five years after a previous dose of tetanus toxoid-containing vaccine; no Arthus cases were reported. We conclude that Arthus reaction following Tdap is extremely rare. Increasing frequency of repeat Tdap administration in adults in the US did not result in a detectable increase in reporting rates of this phenomenon, confirming the favorable safety profile of Tdap.

Tetanus, diphtheria and acellular pertussis (Tdap) vaccine for prevention of pertussis among adults aged 19 years and older in the United States: A cost-effectiveness analysis

Currently, the Advisory Committee on Immunization Practices recommends one-time tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccination for all adults 19 years and older. This study is designed to evaluate the cost-effectiveness of Tdap vaccination for Tdap-eligible adults aged 19 through 85 in the United States. A cost-effectiveness model was developed to compute costs and health outcomes associated with pertussis among 100,000 Tdap-eligible persons of each age cohort. From the societal perspective, the cost per quality-adjusted life-year (QALY) saved was evaluated under the vaccination scenarios. Sensitivity analyses were also conducted to evaluate the impacts of changes in key variables. All costs were adjusted to 2018 US$ with an annual discount rate of 3% applied to costs and outcomes. The incremental cost-effectiveness ratios (ICERs) for vaccinating US adults aged 19 to 85 with Tdap ranged from $248,000/QALY to $900,000/QALY. The lowest cost per QALY was found to be $248,000 for the age 65 cohort, followed by $332,000 for the cohort of age 19, and followed by $477,000 for the age 50 cohort. Sensitivity analysis showed the most dramatic changes in ICER occurred when changing the underreporting factor, vaccine effectiveness and vaccination costs. While Tdap vaccination may not be as cost effective as predicted earlier, it remains the best available preventive measure against pertussis. Further investigation of the true burden of pertussis disease among adults and the effectiveness of Tdap vaccination in this population is needed to better estimate the impact of Tdap vaccination.

Safety of Co-Administration Versus Separate Administration of the Same Vaccines in Children: A Systematic Literature Review

The growing number of available vaccines that can be potentially co-administered makes the assessment of the safety of vaccine co-administration increasingly relevant but complex. We aimed to synthesize the available scientific evidence on the safety of vaccine co-administrations in children by performing a systematic literature review of studies assessing the safety of vaccine co-administrations in children between 1999 and 2019, in line with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Fifty studies compared co-administered vaccines versus the same vaccines administered separately. The most frequently studied vaccines included quadrivalent meningococcal conjugate (MenACWY) vaccine, diphtheria and tetanus toxoids and acellular pertussis (DTaP) or tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap) vaccines, diphtheria and tetanus toxoids and acellular pertussis adsorbed, hepatitis B, inactivated poliovirus and Haemophilus influenzae type b conjugate (DTaP-HepB-IPV/Hib) vaccine, measles, mumps, and rubella (MMR) vaccine, and pneumococcal conjugate 7-valent (PCV7) or 13-valent (PCV13) vaccines. Of this, 16% (n = 8) of the studies reported significantly more adverse events following immunization (AEFI) while in 10% (n = 5) significantly fewer adverse events were found in the co-administration groups. Statistically significant differences between co-administration and separate administration were found for 16 adverse events, for 11 different vaccine co-administrations. In general, studies briefly described safety and one-third of studies lacked any statistical assessment of AEFI. Overall, the evidence on the safety of vaccine co-administrations compared to separate vaccine administrations is inconclusive and there is a paucity of large post-licensure studies addressing this issue.

Use of routinely collected electronic healthcare data for postlicensure vaccine safety signal detection: a systematic review

Background

Concerns regarding adverse events following vaccination (AEFIs) are a key challenge for public confidence in vaccination. Robust postlicensure vaccine safety monitoring remains critical to detect adverse events, including those not identified in prelicensure studies, and to ensure public safety and public confidence in vaccination. We summarise the literature examined AEFI signal detection using electronic healthcare data, regarding data sources, methodological approach and statistical analysis techniques used.

Methods

We performed a systematic review using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Five databases (PubMed/Medline, EMBASE, CINAHL, the Cochrane Library and Web of Science) were searched for studies on AEFIs monitoring published up to 25 September 2017. Studies were appraised for methodological quality, and results were synthesised narratively.

Result

We included 47 articles describing AEFI signal detection using electronic healthcare data. All studies involved linked diagnostic healthcare data, from the emergency department, inpatient and outpatient setting and immunisation records. Statistical analysis methodologies used included non-sequential analysis in 33 studies, group sequential analysis in two studies and 12 studies used continuous sequential analysis. Partially elapsed risk window and data accrual lags were the most cited barriers to monitor AEFIs in near real-time.

Conclusion

Routinely collected electronic healthcare data are increasingly used to detect AEFI signals in near real-time. Further research is required to check the utility of non-coded complaints and encounters, such as telephone medical helpline calls, to enhance AEFI signal detection.

Trial registration number

CRD42017072741.

The use of natural language processing to identify Tdap-related local reactions at five health care systems in the Vaccine Safety Datalink

OBJECTIVE

Local reactions are the most common vaccine-related adverse event. There is no specific diagnosis code for local reaction due to vaccination. Previous vaccine safety studies used non-specific diagnosis codes to identify potential local reaction cases and confirmed the cases through manual chart review. In this study, a natural language processing (NLP) algorithm was developed to identify local reaction associated with tetanus-diphtheria-acellular pertussis (Tdap) vaccine in the Vaccine Safety Datalink.

METHODS

Presumptive cases of local reactions were identified among members ≥ 11 years of age using ICD-9-CM codes in all care settings in the 1-6 days following a Tdap vaccination between 2012 and 2014. The clinical notes were searched for signs and symptoms consistent with local reaction. Information on the timing and the location of a sign or symptom was also extracted to help determine whether or not the sign or symptom was vaccine related. Reactions triggered by causes other than Tdap vaccination were excluded. The NLP algorithm was developed at the lead study site and validated on a stratified random sample of 500 patients from five institutions.

RESULTS

The NLP algorithm achieved an overall weighted sensitivity of 87.9%, specificity of 92.8%, positive predictive value of 82.7%, and negative predictive value of 95.1%. In addition, using data at one site, the NLP algorithm identified 3326 potential Tdap-related local reactions that were not identified through diagnosis codes.

CONCLUSION

The NLP algorithm achieved high accuracy, and demonstrated the potential of NLP to reduce the efforts of manual chart review in vaccine safety studies.

Prevention of Pertussis, Tetanus, and Diphtheria with Vaccines in the United States: Recommendations of the Advisory Committee on Immunization Practices (ACIP)

This report compiles and summarizes all recommendations from CDC's Advisory Committee on Immunization Practices (ACIP) regarding prevention and control of tetanus, diphtheria, and pertussis in the United States. As a comprehensive summary of previously published recommendations, this report does not contain any new recommendations and replaces all previously published reports and policy notes; it is intended for use by clinicians and public health providers as a resource. ACIP recommends routine vaccination for tetanus, diphtheria, and pertussis. Infants and young children are recommended to receive a 5-dose series of diphtheria and tetanus toxoids and acellular pertussis (DTaP) vaccines, with one adolescent booster dose of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine. Adults who have never received Tdap also are recommended to receive a booster dose of Tdap. Women are recommended to receive a dose of Tdap during each pregnancy, which should be administered from 27 through 36 weeks’ gestation, regardless of previous receipt of Tdap. After receipt of Tdap, adolescents and adults are recommended to receive a booster tetanus and diphtheria toxoids (Td) vaccine every 10 years to assure ongoing protection against tetanus and diphtheria.

Concomitant Adolescent Vaccination in the U.S., 2007-2012

INTRODUCTION

Concomitant (same-day) delivery of two or more vaccines to adolescents is effective, safe, and efficient. Increasing concomitant vaccination could improve coverage for recommended adolescent vaccines, but little is known about who receives vaccines concomitantly.

METHODS

Data came from healthcare provider-verified records on 70,144 adolescents (aged 13-17 years) in the 2008-2012 versions of the National Immunization Survey-Teen who had received at least one dose of tetanus, diphtheria, and acellular pertussis (Tdap) booster; meningococcal conjugate vaccine (MenACWY); or human papillomavirus (HPV) vaccine. Separately for each vaccine, multivariable logistic regression identified adolescent and household correlates of concomitant versus single vaccination, stratified by adolescent sex. Vaccination took place in 2007-2012, data collection in 2008-2012, and data analysis in 2015.

RESULTS

Among vaccinated adolescents, 51%-65% of girls and 25%-53% of boys received two vaccines concomitantly. Concomitant uptake of each vaccine increased over survey years (e.g., 2012 vs 2008: girls' Tdap booster, OR=1.88, 95% CI=1.56, 2.26; boys' Tdap booster, OR=2.62, 95% CI=2.16, 3.16), with the exception of HPV vaccination among boys. Additionally, concomitant vaccination was less common as adolescents got older and in the Northeast (all p<0.05). For MenACWY and HPV vaccine, concomitant uptake was less common for girls whose mothers had higher versus lower education and for boys who lived in metropolitan versus non-metropolitan areas (all p<0.05).

CONCLUSIONS

Missed opportunities for concomitant adolescent vaccination persist, particularly for HPV vaccine. Future interventions targeting groups with low rates of concomitant vaccination could improve population-level coverage with recommended vaccines.

Sepsis, parenteral vaccination and skin disinfection

ASBSTRACT Disinfection should be required for all skin penetrative procedures including parenteral administration of vaccines. This review analyses medically attended infectious events following parenteral vaccination in terms of their microbiological aetiology and pathogenesis. Like 'clean' surgical site infections, the major pathogens responsible for these events were Staphylococcal species, implicating endogenous con-tamination as a significant source of infection. As 70% isopropyl alcohol swabbing has been shown to effectively disinfect the skin, it would be medico-legally difficult to defend a case of sepsis with the omission of skin disinfection unless the very low risk of this event was adequately explained to the patient and documented prior to vaccination. There was a significant cost-benefit for skin disinfection and cellulitis. Skin disinfection in the context of parenteral vaccination represents a new paradigm of medical practice; the use of a low cost intervention to prevent an event of very low prevalence but of significant cost.

Best vaccination practice and medically attended injection site events following deltoid intramuscular injection

Analysis of medically attended injection site events data provides a vehicle to appreciate the inadequacies of vaccination practice for deltoid intramuscular injection and to develop best practice procedures. These data can be divided into 3 groups; nerve palsies, musculoskeletal injuries and cutaneous reactions and reflect inappropriate site of injection, needle over or under penetration, local sepsis and vascular complications. The aim of this review is to formulate best vaccination practice procedures for deltoid intramuscular injection of vaccines through the collation and analysis of medically attended injection site events.

Safety of the yellow Fever vaccine: a retrospective study

BACKGROUND

Yellow fever (YF) vaccine is considered safe; however, severe illness and death following vaccination have been reported.

METHODS

Vaccine Safety Datalink (VSD) and US Department of Defense (DoD) data were used to identify adverse reactions following YF vaccination. Within the VSD, YF-vaccine-exposed subjects were compared to age-, site-, and gender-matched unexposed subjects. YF-vaccine-exposed DoD subjects were studied using a risk-interval design. For both cohorts, ICD-9 codes were analyzed for allergic and local reactions, mild systemic reactions, and possible visceral and neurologic adverse events (AEs).

RESULTS

The VSD cohort received 47,159 doses from 1991 through 2006. The DoD cohort received 1.12 million doses from 1999 through 2007. Most subjects received other vaccines simultaneously. In the VSD cohort, rates of allergic, local, and mild systemic reactions were not statistically different between YF-vaccine-exposed and -unexposed subjects. In the DoD, there was an increased risk for outpatient allergic events in the period following vaccination with YF and other vaccines rate ratios [RR 3.85, 95% confidence interval (CI) 3.35-4.41] but with no increased risk for inpatient allergic reactions. In both cohorts, inpatient ICD-9 codes for visceral events were significantly less common following vaccination; inpatient codes for neurologic events were less common in the VSD YF-vaccine-exposed adult cohort, but did not differ between exposed and unexposed periods in the DoD. In the DoD, one fatal case of YF-vaccine-associated viscerotropic disease (YF-vaccine-AVD) was detected. The estimated death rate was 0.89 for 1,000,000 YF vaccine doses (95% CI 0.12-6.31/1,000,000 doses). No YF vaccine-associated deaths occurred in the VSD.

CONCLUSIONS

In these closed cohorts we did not detect increased risk for visceral or neurologic events following YF vaccination. The death rate following YF vaccine was consistent with previous reports. These data support current recommendations for use of YF vaccine in young healthy individuals. These data are inadequate to judge safety of YF vaccines in elderly patients.

Safety of a tetanus-diphtheria-acellular pertussis vaccine when used off-label in an elderly population

BACKGROUND

Published data on the safety of tetanus-diphtheria-acellular pertussis vaccine (Tdap) in persons aged ≥65 years are limited. This study aims to examine a large cohort of Tdap users ≥65 years for evidence of increased risk of adverse events following vaccination.

METHODS

A matched cohort study design and a self-controlled case series (SCCS) design were used. The study population was adults aged ≥65 years who received the Tdap or tetanus and diphtheria (Td) vaccine during 1 January 2006-31 December 2010 at 7 health maintenance organizations in the United States. Seven major groups of prespecified events were identified electronically by diagnostic codes.

RESULTS

The study included 119 573 Tdap vaccinees and the same number of Td vaccinees. The results indicated that the risk of the prespecified events following Tdap was comparable to that following Td vaccination in this elderly population. There was a small increased rate of codes suggesting medically attended inflammatory or allergic events in 1-6 days following Tdap in the SCCS analysis (incidence rate ratio, 1.59 [95% confidence interval, 1.40-1.81]).

CONCLUSION

Although there is a small increased risk of medically attended inflammatory or allergic events in 1-6 days following Tdap compared to other time periods, it is no more common than that following Td. This study provides empirical safety data suggesting that immunizing adults aged ≥65 years with Tdap to reduce the risk of pertussis in the elderly and their contacts should not have untoward safety consequences.

Safety of zoster vaccine in adults from a large managed-care cohort: a Vaccine Safety Datalink study

OBJECTIVES

The aim of this study was to examine a large cohort of adults who received the zoster vaccine for evidence of an increased risk of prespecified adverse events requiring medical attention.

DESIGN

Two self-comparison approaches, including a case-centred approach and a self-controlled case series (SCCS) analysis were used.

SETTING

Eight managed-care organizations participating in the Vaccine Safety Datalink project in the United States.

SUBJECTS

A total of 193 083 adults aged 50 and older receiving a zoster vaccine from 1 January 2007 to 31 December 2008 were included.

MAIN OUTCOME MEASURES

Prespecified adverse events were identified by aggregated International Classification of Diseases, Ninth Revision (ICD-9) codes in automated health plan datasets.

RESULTS

The risk of allergic reaction was significantly increased within 1-7 days of vaccination [relative risk = 2.13, 95% confidence interval (CI): 1.87-2.40 by case-centred method and relative rate = 2.32, 95% CI: 1.85-2.91 by SCCS]. No increased risk was found for the following adverse event groupings: cerebrovascular events; cardiovascular events; meningitis; encephalitis; and encephalopathy; and Ramsay-Hunt syndrome and Bell's palsy.

CONCLUSIONS

The results of this study support the findings from the prelicensure clinical trials, providing reassurance that the zoster vaccine is generally safe and well-tolerated with a small increased risk of allergic reactions in 1-7 days after vaccination.

Additional recommendations for use of tetanus toxoid, reduced-content diphtheria toxoid, and acellular pertussis vaccine (Tdap)

The American Academy of Pediatrics and the Centers for Disease Control and Prevention are amending previous recommendations and making additional recommendations for the use of tetanus toxoid, reduced-content diphtheria toxoid, and acellular pertussis vaccine (Tdap). Review of the results from clinical trials and other studies has revealed no excess reactogenicity when Tdap is given within a short interval after other tetanus- or diphtheria-containing toxoid products, and accrual of postmarketing adverse-events reports reveals an excellent safety record for Tdap. Thus, the recommendation for caution regarding Tdap use within any interval after a tetanus- or diphtheria-containing toxoid product is removed. Tdap should be given when it is indicated and when no contraindication exists. In further efforts to protect people who are susceptible to pertussis, the American Academy of Pediatrics and Centers for Disease Control and Prevention recommend a single dose of Tdap for children 7 through 10 years of age who were underimmunized with diphtheria-tetanus-acellular pertussis (DTaP). Also, the age for recommendation for Tdap is extended to those aged 65 years and older who have or are likely to have contact with an infant younger than 12 months (eg, health care personnel, grandparents, and other caregivers).

Injection site and risk of medically attended local reactions to acellular pertussis vaccine

OBJECTIVE

To assess whether the risk of medically attended local reactions to the fifth dose of the diphtheria and tetanus toxoids and acellular pertussis (DTaP) vaccine varies according to injection site (arm versus thigh).

METHODS

We conducted a retrospective cohort study of children aged 4 through 6 years in the Vaccine Safety Datalink population who received a DTaP vaccination during the period from 2002 through 2006. Medically attended local reactions to the DTaP vaccine were presumptively identified from administrative data and were confirmed by medical record review.

RESULTS

Among the 233,616 children in the study population, 1017 (0.4%) had a confirmed medically attended local reaction to the fifth dose of the DTaP vaccine. The rate of those reactions was significantly higher with vaccinations given in the arm (47.4 per 10,000 vaccinations) compared with vaccinations given in the thigh (32.1 per 10,000 vaccinations) (P < .001). In a multivariable analysis adjusted for age, gender, and study site, children vaccinated in the arm had a 78% higher risk of a local reaction (relative risk: 1.78 [95% confidence interval: 1.43-2.21]).

CONCLUSIONS

Local reactions to the fifth dose of the DTaP vaccine that require medical evaluation are uncommon, but the risk of those reactions is significantly higher when the vaccine is injected in the arm. These findings suggest that the thigh should be considered as an acceptable site of injection for this vaccination.

Receipt of tetanus-containing vaccinations among adolescents aged 13 to 17 years in the United States: National Immunization Survey-Teen 2007

BACKGROUND

Tetanus-diphtheria-acellular pertussis (Tdap) was licensed in the United States in 2005 to be given in place of tetanus-diphtheria (Td) for single use in adolescents.

OBJECTIVES

This analysis was conducted to determine vaccination coverage with Td and Tdap among adolescents in the United States aged 13 to 17 years and to characterize adolescents who had not received a tetanus-containing booster vaccine.

METHODS

Data were analyzed from the National Immunization Survey-Teen (NIS-Teen) 2007, a random-digit-dialing telephone survey that is weighted to be nationally representative of adolescents aged 13 to 17 years. Parents gave verbal consent so that vaccination providers could be contacted to obtain the adolescents' immunization histories. Weighted coverage of Td and Tdap vaccines was estimated with bivariate analysis from returned vaccination data from the providers' records. A multivariable analysis was conducted to determine factors independently associated with nonreceipt of tetanus-containing vaccines. Missed opportunities for vaccination with Td or Tdap were determined from documented vaccination visits for other vaccines.

RESULTS

Out of 69,289 households screened, 6572 had an eligible adolescent aged 13 to 17 years and 5486 (83.5%) completed the household interview. Among 5474 adolescents who met the age criterion and completed a household interview, consent to contact providers was obtained for 4114 (75.2%). A total of 2947 adolescents (53.7% of those with completed household interviews) had immunization histories returned from providers for verification. In 2007, a total of 2149 adolescents (weighted percentage, 72.3%) aged 13 to 17 years had received at least one tetanus booster since age 10 years; Tdap coverage was 30.4%. The mean (SE) age at Td or Tdap receipt was 13.04 (0.04) years (range, 10.00-17.84 years); the median age was 12.86 years. More than half (59.4%) of sampled adolescents had received their booster dose on or after January 1, 2005; among those vaccinated in 2007, 89.1% received Tdap as their booster dose. Factors associated with nonreceipt of Td or Tdap included geographic location and not having a provider-reported well-child visit at ages 11 to 12 years.

CONCLUSIONS

Almost three quarters of adolescents aged 13 to 17 years included in the NIS-Teen 2007 received a tetanus-containing vaccine, and almost one third received Tdap. Among adolescents who received a tetanus-containing vaccine in 2007, a total of 89.1% received the new Tdap vaccine in place of Td, as recommended. Adolescents not receiving Td or Tdap may face barriers to accessing health care. Research is needed to identify evidence-based strategies to improve vaccination coverage among adolescents.

The safety of immunizing with tetanus-diphtheria-acellular pertussis vaccine (Tdap) less than 2 years following previous tetanus vaccination: Experience during a mass vaccination campaign of healthcare personnel during a respiratory illness outbreak

BACKGROUND

Tdap is recommended for health care personnel (HCP) aged <65 years who received tetanus diphtheria or tetanus toxoid immunization (Td/TT) ≥2 years earlier. During a medical center Tdap vaccination campaign, we assessed the safety of use of a Td/TT to Tdap interval <2 years in HCP. We also describe reactogenicity in HCP who were aged ≥65 years or pregnant.

METHODS

HCP vaccinated with Tdap were surveyed to assess time since last Td/TT (≥2 years vs. <2 years), age, pregnancy status, and injection site adverse events (AEs) during the 2 weeks after Tdap. AE rates were calculated and compared by non-inferiority analysis using a predetermined margin of 10%. We searched clinic logbooks to assess for clinically important adverse events during the 2 months after Tdap.

RESULTS

Of the 4524 vaccinated HCP, 2221 (49.1%) completed a safety survey which met criteria for analysis. Non-inferiority analysis found that rates of moderate and/or severe injection site AEs were not significantly greater in those vaccinated <2 years than in those vaccinated ≥2 years after previous Td/TT. Three serious adverse events were reported during the 2 months after vaccination, none in persons who were ≥65 years, pregnant or received Td/TT <2 years before.

CONCLUSIONS

Our findings add to the body of evidence that a short interval between Td/TT and a single dose of Tdap is safe.