Recent developments in the understanding and use of anthrax vaccine adsorbed: achieving more with less

Anthrax Vaccine Adsorbed (AVA, BioThrax™) is the only Food and Drug Administration (FDA) approved vaccine for the prevention of anthrax in humans. Recent improvements in pre-exposure prophylaxis (PrEP) use of AVA include intramuscular (IM) administration and simplification of the priming series to three doses over 6 months. Administration IM markedly reduced the frequency, severity and duration of injection site reactions. Refinement of animal models for inhalation anthrax, identification of immune correlates of protection and cross-species modeling have created opportunities for reductions in the PrEP booster schedule and were pivotal in FDA approval of a post-exposure prophylaxis (PEP) indication. Clinical and nonclinical studies of accelerated PEP schedules and divided doses may provide prospects for shortening the PEP antimicrobial treatment period. These data may assist in determining feasibility of expanded coverage in a large-scale emergency when vaccine demand may exceed availability. Enhancements to the AVA formulation may broaden the vaccine's PEP application.

Risk of anaphylaxis after vaccination in children and adults

BACKGROUND

Anaphylaxis is a potentially life-threatening allergic reaction. The risk of anaphylaxis after vaccination has not been well described in adults or with newer vaccines in children.

OBJECTIVE

We sought to estimate the incidence of anaphylaxis after vaccines and describe the demographic and clinical characteristics of confirmed cases of anaphylaxis.

METHODS

Using health care data from the Vaccine Safety Datalink, we determined rates of anaphylaxis after vaccination in children and adults. We first identified all patients with a vaccination record from January 2009 through December 2011 and used diagnostic and procedure codes to identify potential anaphylaxis cases. Medical records of potential cases were reviewed. Confirmed cases met the Brighton Collaboration definition for anaphylaxis and had to be determined to be vaccine triggered. We calculated the incidence of anaphylaxis after all vaccines combined and for selected individual vaccines.

RESULTS

We identified 33 confirmed vaccine-triggered anaphylaxis cases that occurred after 25,173,965 vaccine doses. The rate of anaphylaxis was 1.31 (95% CI, 0.90-1.84) per million vaccine doses. The incidence did not vary significantly by age, and there was a nonsignificant female predominance. Vaccine-specific rates included 1.35 (95% CI, 0.65-2.47) per million doses for inactivated trivalent influenza vaccine (10 cases, 7,434,628 doses given alone) and 1.83 (95% CI, 0.22-6.63) per million doses for inactivated monovalent influenza vaccine (2 cases, 1,090,279 doses given alone). The onset of symptoms among cases was within 30 minutes (8 cases), 30 to less than 120 minutes (8 cases), 2 to less than 4 hours (10 cases), 4 to 8 hours (2 cases), the next day (1 case), and not documented (4 cases).

CONCLUSION

Anaphylaxis after vaccination is rare in all age groups. Despite its rarity, anaphylaxis is a potentially life-threatening medical emergency that vaccine providers need to be prepared to treat.

Vaccination and 30-Day Mortality Risk in Children, Adolescents, and Young Adults

OBJECTIVE

This study evaluates the potential association of vaccination and death in the Vaccine Safety Datalink (VSD).

METHODS

The study cohort included individuals ages 9 to 26 years with deaths between January 1, 2005, and December 31, 2011. We implemented a case-centered method to estimate a relative risk (RR) for death in days 0 to 30 after vaccination.Deaths due to external causes (accidents, homicides, and suicides) were excluded from the primary analysis. In a secondary analysis, we included all deaths regardless of cause. A team of physicians reviewed available medical records and coroner's reports to confirm cause of death and assess the causal relationship between death and vaccination.

RESULTS

Of the 1100 deaths identified during the study period, 76 (7%) occurred 0 to 30 days after vaccination. The relative risks for deaths after any vaccination and influenza vaccination were significantly lower for deaths due to nonexternal causes (RR 0.57, 95% confidence interval [CI] 0.38-0.83, and RR 0.44, 95% CI 0.24-0.80, respectively) and deaths due to all causes (RR 0.72, 95% CI 0.56-0.91, and RR 0.44, 95% CI 0.28-0.65). No other individual vaccines were significantly associated with death. Among deaths reviewed, 1 cause of death was unknown, 25 deaths were due to nonexternal causes, and 34 deaths were due to external causes. The causality assessment found no evidence of a causal association between vaccination and death.

CONCLUSIONS

Risk of death was not increased during the 30 days after vaccination, and no deaths were found to be causally associated with vaccination.

Association of Tdap Vaccination With Acute Events and Adverse Birth Outcomes Among Pregnant Women With Prior Tetanus-Containing Immunizations

IMPORTANCE

The Advisory Committee on Immunization Practices (ACIP) recommends the tetanus, diphtheria, and acellular pertussis (Tdap) vaccine for pregnant women during each pregnancy, regardless of prior immunization status. However, safety data on repeated Tdap vaccination in pregnancy is lacking.

OBJECTIVE

To determine whether receipt of Tdap vaccine during pregnancy administered in close intervals from prior tetanus-containing vaccinations is associated with acute adverse events in mothers and adverse birth outcomes in neonates.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study in 29,155 pregnant women aged 14 through 49 years from January 1, 2007, through November 15, 2013, using data from 7 Vaccine Safety Datalink sites in California, Colorado, Minnesota, Oregon, Washington, and Wisconsin.

EXPOSURES

Women who received Tdap in pregnancy following a prior tetanus-containing vaccine less than 2 years before, 2 to 5 years before, and more than 5 years before.

MAIN OUTCOMES AND MEASURES

Acute adverse events (fever, allergy, and local reactions) and adverse birth outcomes (small for gestational age, preterm delivery, and low birth weight) were evaluated. Women who were vaccinated with Tdap in pregnancy and had a prior tetanus-containing vaccine more than 5 years before served as controls.

RESULTS

There were no statistically significant differences in rates of medically attended acute adverse events or adverse birth outcomes related to timing since prior tetanus-containing vaccination. [table: see text].

CONCLUSIONS AND RELEVANCE

Among women who received Tdap vaccination during pregnancy, there was no increased risk of acute adverse events or adverse birth outcomes for those who had been previously vaccinated less than 2 years before or 2 to 5 years before compared with those who had been vaccinated more than 5 years before. These findings suggest that relatively recent receipt of a prior tetanus-containing vaccination does not increase risk after Tdap vaccination in pregnancy.

The Centers for Disease Control and Prevention's public health response to monitoring Tdap safety in pregnant women in the United States

In 2010, in response to a widespread pertussis outbreak and neonatal deaths, California became the first state to recommend routine administration of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine during pregnancy. In 2011, the Advisory Committee on Immunization Practices (ACIP) followed with a similar recommendation for Tdap vaccination during pregnancy for previously unvaccinated women. In 2012, this recommendation was expanded to include Tdap vaccination of every pregnant woman during each pregnancy. These recommendations were based on urgent public health needs and available evidence on the safety of other inactivated vaccines during pregnancy. However, there were limited data on the safety of Tdap during pregnancy. In response to the new ACIP recommendations, the Centers for Disease Control and Prevention (CDC) implemented ongoing collaborative studies to evaluate whether vaccination with Tdap during pregnancy adversely affects the health of mothers and their offspring and provide the committee with regular updates. The current commentary describes the public health actions taken by CDC to respond to the ACIP recommendation to study and monitor the safety of Tdap vaccines in pregnant women and describes the current state of knowledge on the safety of Tdap vaccines in pregnant women. Data from the various monitoring activities support the safety of Tdap use during pregnancy.

Military healthcare providers reporting of adverse events following immunizations to the vaccine adverse event reporting system

OBJECTIVES

We studied military health care provider (HCP) practices regarding reporting of adverse events following immunization (AEFI).

METHODS

A convenience sample of HCP was surveyed to assess familiarity with Vaccine Adverse Event Reporting System (VAERS), AEFI they were likely to report, methods used and preferred for reporting, and perceived barriers to reporting. We analyzed factors associated with HCP reporting AEFI to VAERS.

RESULTS

A total of 547 surveys were distributed with 487 completed and returned for an 89% response rate. The percentage of HCP aware of VAERS (54%) varied by occupation. 47% of respondents identified knowledge of at least one AEFI with only 34% of these indicating that they had ever reported to VAERS. More serious events were more likely to be reported. Factors associated with HCP reporting AEFIs in bivariate analysis included HCP familiarity with filing a paper VAERS report, HCP familiarity with filing an electronic VAERS report, HCP familiarity with VAERS, and time spent on immunization tasks. In a multivariable analysis, only HCP familiarity with filing a paper VAERS report was statistically significant (Odds ratio = 115.3; p < 0.001).

CONCLUSIONS

Specific educational interventions targeted to military HCP likely to see AEFIs but not currently filing VAERS reports may improve vaccine safety reporting practices.

Adverse Events Following Measles, Mumps, and Rubella Vaccine in Adults Reported to the Vaccine Adverse Event Reporting System (VAERS), 2003-2013

BACKGROUND

Limited data exist on the safety of the measles, mumps, and rubella (MMR) vaccine in adults. We reviewed reports of adverse events (AEs) to the Vaccine Adverse Event Reporting System (VAERS) to assess safety in this previously understudied group.

METHODS

VAERS is the national spontaneous vaccine safety surveillance system coadministered by the Centers for Disease Control and Prevention and the US Food and Drug Administration. We searched the VAERS database for US reports of adults aged ≥19 years who received the MMR vaccine from 1 January 2003 to 31 July 2013. We clinically reviewed reports and available medical records for serious AEs, pregnancy reports, and reports for selected prespecified outcomes.

RESULTS

During this period, VAERS received 3175 US reports after MMR vaccine in adults. Of these, 168 (5%) were classified as serious, including 7 reports of death. Females accounted for 77% of reports. The most common signs and symptoms for all reports were pyrexia (19%), rash (17%), pain (13%), and arthralgia (13%). We did not detect any new safety findings in empirical Bayesian data mining. We identified 131 reports of MMR vaccine administered to a pregnant woman; the majority of these vaccinations were in the first trimester and in 83 (62%), no AE was reported.

CONCLUSIONS

In our review of VAERS data, we did not detect any new or unexpected safety concerns for MMR vaccination in adults. We identified reports of pregnant women exposed to MMR, which is a group in whom the vaccine is contraindicated, suggesting the need for continued provider education on vaccine recommendations and screening.

Evaluation of sex, race, body mass index and pre-vaccination serum progesterone levels and post-vaccination serum anti-anthrax protective immunoglobulin G on injection site adverse events following anthrax vaccine adsorbed (AVA) in the CDC AVA human clinical trial

BACKGROUND

Anthrax vaccine adsorbed (AVA) administered intramuscularly (IM) results in fewer adverse events (AEs) than subcutaneous (SQ) administration. Women experience more AEs than men. Antibody response, female hormones, race, and body mass index (BMI) may contribute to increased frequency of reported injection site AEs.

METHODS

We analyzed data from the CDC AVA human clinical trial. This double blind, randomized, placebo controlled trial enrolled 1563 participants and followed them through 8 injections (AVA or placebo) over a period of 42 months. For the trial's vaccinated cohort (n=1267), we used multivariable logistic regression to model the effects of study group (SQ or IM), sex, race, study site, BMI, age, and post-vaccination serum anti-PA IgG on occurrence of AEs of any severity grade. Also, in a women-only subset (n=227), we assessed effect of pre-vaccination serum progesterone level and menstrual phase on AEs.

RESULTS

Participants who received SQ injections had significantly higher proportions of itching, redness, swelling, tenderness and warmth compared to the IM study group after adjusting for other risk factors. The proportions of redness, swelling, tenderness and warmth were all significantly lower in blacks vs. non-black participants. We found arm motion limitation, itching, pain, swelling and tenderness were more likely to occur in participants with the highest anti-PA IgG concentrations. In the SQ study group, redness and swelling were more common for obese participants compared to participants who were not overweight. Females had significantly higher proportions of all AEs compared to males. Menstrual phase was not associated with any AEs.

CONCLUSIONS

Female and non-black participants had a higher proportion of AVA associated AEs and higher anti-PA IgG concentrations. Antibody responses to other vaccines may also vary by sex and race. Further studies may provide better understanding for higher proportions of AEs in women and non-black participants.

Assessing agreement of repeated binary measurements with an application to the CDC's anthrax vaccine clinical trial

Cohen's kappa coefficient, which was introduced in 1960, serves as the most widely employed coefficient to assess inter-observer agreement for categorical outcomes. However, the original kappa can only be applied to cross-sectional binary measurements and, therefore, cannot be applied in the practical situation when the observers evaluate the same subjects at repeated time intervals. This study summarizes six methods of assessing agreement of repeated binary outcomes under different assumptions and discusses under which condition we should use the most appropriate method in practice. These approaches are illustrated using data from the CDC anthrax vaccine adsorbed (AVA) human clinical trial comparing the agreement for two solicited adverse events after AVA between the 1-3 day in-clinic medical record and the patient's diary on the same day. We hope this article can inspire researchers to choose the most appropriate method to assess agreement for their own study with longitudinal binary data.

Who is unlikely to report adverse events after vaccinations to the Vaccine Adverse Event Reporting System (VAERS)?

BACKGROUND

Healthcare provider (HCP) reporting to the Vaccine Adverse Event Reporting System (VAERS) is important to assuring the safety of U.S. licensed vaccines. HCP awareness of and practices regarding reporting of adverse events following immunization (AEFI) is understudied.

METHODS

A large, nationally representative sample of U.S. office-based HCP across three occupational groups (physicians, mid-level providers [physician assistants, advanced practice nurses] and nurses) and three primary care practice areas (pediatrics, family medicine, internal medicine) were surveyed utilizing standardized methodology. We assessed HCP familiarity with VAERS, the situations under which they were likely to report an AEFI, and the methods they used and preferred for reporting. We used logistic regression to determine factors associated with HCP not reporting AEFI to VAERS.

RESULTS

Our survey response rate was 54.9%. The percentage of HCP aware of VAERS (71%) varied by occupation and primary care practice area. About 37% of HCP had identified at least one AEFI with only 17% of these indicating that they had ever reported to VAERS. More serious events were more likely to be reported. Factors associated with HCP not reporting AEFI included: HCP not familiar versus very familiar with filing a paper VAERS report (OR=12.84; p<0.0001), primary care practice area of internal medicine versus pediatrics (OR=4.22; p=0.0005), and HCP not familiar versus very familiar with when it was required to file a VAERS report (OR=5.52; p=0.0013).

CONCLUSIONS

Specific educational interventions targeted to HCP likely to see AEFI but not currently reporting may improve vaccine safety reporting practices.

Health-related quality of life in the CDC Anthrax Vaccine Adsorbed Human Clinical Trial

BACKGROUND

After the Department of Defense implemented a mandatory anthrax vaccination program in 1998 concerns were raised about potential long-term safety effects of the current anthrax vaccine. The CDC multicenter, randomized, double-blind, placebo-controlled Anthrax Vaccine Adsorbed (AVA) Human Clinical Trial to evaluate route change and dose reduction collected data on participants' quality of life. Our objective is to assess the association between receipt of AVA and changes in health-related quality of life, as measured by the SF-36 health survey (Medical Outcomes Trust, Boston, MA), over 42 months after vaccination.

METHODS

1562 trial participants completed SF-36v2 health surveys at 0, 12, 18, 30 and 42 months. Physical and mental summary scores were obtained from the survey results. We used Generalized Estimating Equations (GEE) analyses to assess the association between physical and mental score difference from baseline and seven study groups receiving either AVA at each dose, saline placebo at each dose, or a reduced AVA schedule substituting saline placebo for some doses.

RESULTS

Overall, mean physical and mental scores tended to decrease after baseline. However, we found no evidence that the score difference from baseline changed significantly differently between the seven study groups.

CONCLUSIONS

These results do not favor an association between receipt of AVA and an altered health-related quality of life over a 42-month period.

Vaccination and risk of type 1 diabetes mellitus in active component U.S. Military, 2002-2008

AIMS/HYPOTHESIS

To evaluate whether vaccination increases the risk of type 1 diabetes mellitus in active component U.S. military personnel.

METHODS

We conducted a retrospective cohort study among active component U.S. military personnel age 17-35 years. Individuals with first time diagnoses of type 1 diabetes between January 1, 2002 and December 31, 2008 were identified using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. We used Poisson regression to estimate risk ratios between individual vaccine exposures and type 1 diabetes. Secondary analyses were performed controlling for receipt of multiple vaccines and available demographic variables.

RESULTS

Our study population consisted of 2,385,102 individuals followed for approximately 7,644,098 person-years of service. This included 1074 incident type 1 diabetes cases. We observed no significant increased risk of type 1 diabetes after vaccination with anthrax vaccine adsorbed (AVA) [RR=1.00; 95% CI (0.85, 1.17)], smallpox vaccine [RR=0.84; 95% (CI 0.70, 1.01)], typhoid vaccine [RR=1.03; 95% CI (0.87, 1.22)], hepatitis B vaccine [RR=0.83; 95% CI (0.72, 0.95)], measles mumps rubella vaccine (MMR) [RR=0.71, 95% CI (0.61, 0.83)], or yellow fever vaccine [RR=0.70; 95% CI (0.59, 0.82)].

CONCLUSIONS

We did not find an increased risk of diagnosed type 1 diabetes and any of the study vaccines. We recommend that follow-up studies using medical record review to confirm case status should be considered to corroborate these findings.

Effects of a reduced dose schedule and intramuscular administration of anthrax vaccine adsorbed on immunogenicity and safety at 7 months: a randomized trial

CONTEXT

In 1999, the US Congress directed the Centers for Disease Control and Prevention to conduct a pivotal safety and efficacy study of anthrax vaccine adsorbed (AVA).

OBJECTIVE

To determine the effects on serological responses and injection site adverse events (AEs) resulting from changing the route of administration of AVA from subcutaneous (s.q.) to intramuscular (i.m.) and omitting the week 2 dose from the licensed schedule.

DESIGN, SETTING, AND PARTICIPANTS

Assessment of the first 1005 enrollees in a multisite, randomized, double-blind, noninferiority, phase 4 human clinical trial (ongoing from May 2002).

INTERVENTION

Healthy adults received AVA by the s.q. (reference group) or i.m. route at 0, 2, and 4 weeks and 6 months (4-SQ or 4-IM; n = 165-170 per group) or at a reduced 3-dose schedule (3-IM; n = 501). A control group (n = 169) received saline injections at the same time intervals.

MAIN OUTCOME MEASURES

Noninferiority at week 8 and month 7 of anti-protective antigen IgG geometric mean concentration (GMC), geometric mean titer (GMT), and proportion of responders with a 4-fold rise in titer (%4 x R). Reactogenicity outcomes were proportions of injection site and systemic AEs.

RESULTS

At week 8, the 4-IM group (GMC, 90.8 microg/mL; GMT, 1114.8; %4 x R, 97.7) was noninferior to the 4-SQ group (GMC, 105.1 microg/mL; GMT, 1315.4; %4 x R, 98.8) for all 3 primary end points. The 3-IM group was noninferior for only the %4 x R (GMC, 52.2 microg/mL; GMT, 650.6; %4 x R, 94.4). At month 7, all groups were noninferior to the licensed regimen for all end points. Solicited injection site AEs assessed during examinations occurred at lower proportions in the 4-IM group compared with 4-SQ. The odds ratio for ordinal end point pain reported immediately after injection was reduced by 50% for the 4-IM vs 4-SQ groups (P < .001). Route of administration did not significantly influence the occurrence of systemic AEs.

CONCLUSIONS

The 4-IM and 3-IM regimens of AVA provided noninferior immunological priming by month 7 when compared with the 4-SQ licensed regimen. Intramuscular administration significantly reduced the occurrence of injection site AEs. Trial Registration clinicaltrials.gov Identifier: NCT00119067.

Concurrent Vaccinations and U.S. Military Hospitalizations

PURPOSE

To investigate whether concurrent vaccinations (> or =2 vaccinations on consecutive days) are associated with hospitalization risk among U.S. military personnel.

METHODS

We analyzed Defense Medical Surveillance System data from January 1998 through December 2003 for 117,876 active component U.S. military personnel. We performed a time-to-event analysis of a historical cohort using a Cox proportional hazards model comparing hospitalizations during a 120-day postvaccination exposure interval to hospitalizations within a 120-day pre-exposure interval. We excluded personnel who were deployed during these intervals and those having hospitalizations 60 days prior to the concurrent vaccination exposure. Hazards ratios (HRs) with 95% confidence intervals were calculated, adjusting for demographic, occupational, health, and calendar variables.

RESULTS

We analyzed 19,743 persons having concurrent vaccinations. Receiving two or more vaccinations concurrently was not statistically associated with the adjusted risk of hospitalization (HR = 0.90 [0.75, 1.09]). Furthermore, no statistically significant associations were detected for 3 concurrent vaccinations (HR = 0.86 [0.58, 1.28]), 4 concurrent vaccinations (HR = 1.08, [0.66, 1.74]), or five or more concurrent vaccinations (HR = 0.86 [0.49, 1.51]).

CONCLUSIONS

No evidence was found that the concurrent receipt of multiple vaccinations is related to hospitalization risk among this sample of U.S. military personnel.

Phenotypic and molecular epidemiologic evaluation of a Nocardia farcinica mastitis epizootic

Nineteen putative Nocardia farcinica isolates epidemiologically associated with intramammary products containing neomycin were obtained from clinical cases in a Canada-wide mastitis epizootic. Epidemiologic investigations were unable to identify the mechanism for transmission. To evaluate the hypotheses generated (intrinsic versus extrinsic contamination) and to confirm the identity of N. farcinica, we compared these isolates phenotypically (biochemicals and antimicrobial susceptibility studies) and genotypically (16S rRNA gene sequencing analysis, chromosomal DNA and ribotyping profiles) with the type and reference strains of N. farcinica. Results of biochemical studies and 16S rRNA gene sequencing identified the isolates as N. farcinica. Results of chromosomal DNA and ribotyping profiles and antimicrobial resistance to amikacin indicated all were a unique clone of N. farcinica that differed from the control isolates. Our study suggests the epizootic was caused by transmission of a unique clone of N. farcinica through intrinsically contaminated dry cow intramammary products rather than an extrinsic source.

A comparative assessment of immunization records in the Defense Medical Surveillance System and the Vaccine Adverse Event Reporting System

We compared immunization data in the Defense Medical Surveillance System (DMSS) and immunization data for service members with an anthrax vaccine-associated adverse event reported to the Vaccine Adverse Event Reporting System (VAERS) during January 1998 through December 2004. Our main measure of agreement was sensitivity of the DMSS conditional on an immunization record(s) occurring in VAERS. The sensitivity of DMSS was 73% for all vaccines and 74% for the anthrax vaccine on the VAERS index immunization date. Our study is the first to quantify the agreement between immunization records in VAERS and DMSS. Our data suggest the immunization information in military VAERS reports and the DMSS is similar for anthrax and non-anthrax immunizations.

Assessment of anthrax vaccination data in the Defense Medical Surveillance System, 1998–2004

PURPOSE

Understanding the completeness and accuracy of U.S. military anthrax vaccination data is important to the design and interpretation of studies to assess the safety of anthrax vaccine. We estimated the agreement between electronically recorded anthrax vaccination data in the Defense Medical Surveillance System (DMSS) versus anthrax vaccination data abstracted from hardcopy medical charts in a representative sample of the U.S. military from 1998 to 2004.

METHODS

Medical chart abstractions were conducted at 28 military treatment facilities for 4201 personnel. Abstracted anthrax vaccination data for 1817 personnel, representing 7400 anthrax vaccine doses, were compared with electronically captured data in the DMSS from 1998 to 2004. Sensitivity, positive predictive value (PPV), specificity and negative predictive value (NPV) were calculated using weighted analyses.

RESULTS

Weighted person-level analysis revealed DMSS sensitivity = 93.8% (95%CI = 91.1, 95.8), specificity = 87.0% (79.0, 92.3), PPV = 85.6% (77.2, 91.3) and NPV = 94.5% (91.7, 96.4). Report of anthrax vaccination within a +/-7 days window in both medical chart and DMSS electronic data had a sensitivity of 88.3% (85.4, 90.7) and a PPV of 86.6% (84.9, 88.2) in the vaccine dose-level analysis.

CONCLUSIONS

These results support that anthrax vaccination data captured by the DMSS are adequate for post-marketing surveillance investigations in the U.S. military and are of comparable quality to data captured by other vaccine safety databases.

Short-term reactogenicity and gender effect of anthrax vaccine: analysis of a 1967–1972 study and review of the 1955–2005 medical literature

PURPOSE

In the 1960s, the Centers for Disease Control and Prevention (CDC) held the investigational new drug (IND) application for the anthrax vaccine and collected short-term safety data from approximately 16,000 doses administered to almost 7000 individuals. While some recent anthrax vaccine safety studies have suggested that women experience more injection site reactions (ISRs), to our knowledge the IND safety data were not previously examined for a gender-specific difference.

METHODS

We identified and analyzed a subset of the IND study data representing a total of 1749 persons who received 3592 doses from 1967 to 1972. Original data collection forms were located and information extracted, including: vaccine recipient's name, age at vaccination, gender, dose number, date of vaccination, lot number, grading of ISR, presence and type of systemic reactions. Overall and gender-specific rates for adverse reactions to anthrax vaccine were calculated and we performed a multivariable analysis.

RESULTS

We found an ISR was associated with 28% of anthrax vaccine doses; however, 87% of these were considered mild. Systemic reactions were uncommon (<1%) and most (70%) accompanied an ISR. Our dose-specific analysis by gender found women had at least twice the risk of having a vaccine reaction compared to men. Our age-adjusted relative risk for ISR in women compared to men was 2.78 (95%CI: 2.29, 3.38).

CONCLUSIONS

Our results for both overall and gender-specific reactogenicity are consistent with other anthrax safety studies. To date, possible implications of these gender differences observed for anthrax and other vaccines are unknown and deserve further study.

Characterization of clinical isolates previously identified as Oerskovia turbata: proposal of Cellulosimicrobium funkei sp. nov. and emended description of the genus Cellulosimicrobium

Taxonomic studies were performed on 13 clinical isolates (ten of which were epidemiologically related) that had been previously identified as Oerskovia turbata. Comparative phylogenetic analysis, based on 16S rRNA gene sequences, indicated that the isolates are closely related to Cellulosimicrobium cellulans with sequence similarity values ranging from 99.5 to 99.8 %. Chemotaxonomic results (fatty acid profiles and menaquinones) supported the inclusion of these isolates in the genus Cellulosimicrobium. The DNA G+C content was 74.5 mol%. The results of DNA-DNA reassociation, whole-cell sugars (with galactose as the characteristic whole sugar) and phenotypic properties, including antimicrobial resistance, indicated that these isolates are representatives of a novel species of the genus Cellulosimicrobium. The name Cellulosimicrobium funkei sp. nov. is proposed for the novel strains, with strain W6122T (=ATCC BAA-886T = DSM 16025T = CCUG 50705T) as the type strain. The definition of this novel Cellulosimicrobium species will assist in the understanding of the epidemiology and clinical significance of these micro-organisms.

Factors influencing laboratory workers' decisions to accept or decline anthrax vaccine adsorbed (AVA): results of a decision-making study in CDC's anthrax vaccination program

BACKGROUND

Laboratory technicians, laboratory supervisors, decontamination/remediation workers, and environmental investigators are at increased risk for repeated occupational exposure to Bacillus anthracis. In 2002, the Advisory Committee on Immunization Practices (ACIP) recommended pre-exposure vaccination for these occupational groups.

OBJECTIVES

To determine (1) the factors that influenced an individual's decision to either accept or decline Anthrax Vaccine Adsorbed (AVA), and (2) if laboratory workers' concern about AVA safety was related to their information needs and trust in the information provided.

METHODS

We conducted a decision-making survey of 404 participants at 44 Laboratory Response Network laboratories located throughout the United States. All participants were enrolled between October 2002 and December 2004, and all were eligible to receive AVA according to the 2002 ACIP recommendations. Chi-square tests and multivariate logistic regression were used in the analyses.

RESULTS

The response rate of eligible individuals at participating laboratories was 94% (404/430). Sixty-six percent of respondents accepted and 34% declined AVA. Laboratory workers who declined AVA were more likely to rate their risk of exposure to inhalation anthrax as low (OR = 6.9; 95%CI 1.7, 28.3), report being very concerned (OR = 4.1; 95%CI 1.8, 9.3) or concerned (OR = 2.0; 95%CI 1.3, 3.1) about the safety of the vaccine, report that they did not trust the information provided in the Vaccine Information Statement (VIS) (OR = 2.3; 95%CI 1.1, 4.5), and to be enrolled in the study during 2002 (OR = 24.7; 95%CI 6.4, 95.3) or 2003 (OR = 5.0; 95%CI 2.5, 9.8), the first 2 years of the study. Furthermore, we found a significant association between a participant's level of concern about the safety of AVA and their perception that they received enough information and/or trusted the information in the VIS.

CONCLUSIONS

Low perceived necessity, concern about the safety of the vaccine, and a lack of trust in the VIS were associated with the decision of laboratory workers to decline AVA. Results of this decision-making study may be used to try to improve acceptance rates of AVA among persons considered at high risk, and may inform educational efforts for other adult vaccines.