Lakshmi Sukumaran

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.

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.

Safety of Tetanus Toxoid, Reduced Diphtheria Toxoid, and Acellular Pertussis and Influenza Vaccinations in Pregnancy.

OBJECTIVE: To evaluate the safety of coadministering tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) and influenza vaccines during pregnancy by comparing adverse events after concomitant and sequential vaccination. METHODS: We conducted a retrospective cohort study of pregnant women aged 14–49 years in the Vaccine Safety Datalink from January 1, 2007, to November 15, 2013. We compared medically attended acute events (fever, any acute reaction) and adverse birth outcomes (preterm delivery, low birth weight, small for gestational age) in women receiving concomitant Tdap and influenza vaccination and women receiving sequential vaccination. RESULTS: Among 36,844 pregnancies in which Tdap and influenza vaccines were administered, the vaccines were administered concomitantly in 8,464 (23%) pregnancies and sequentially in 28,380 (77%) pregnancies. Acute adverse events after vaccination were rare. We found no statistically significant increased risk of fever or any medically attended acute adverse event in pregnant women vaccinated concomitantly compared with sequentially. When analyzing women at 20 weeks of gestation or greater during periods of influenza vaccine administration, there were no differences in preterm delivery, low-birth-weight, or small-for-gestational-age neonates between women vaccinated concomitantly compared with sequentially in pregnancy. CONCLUSION: Concomitant administration of Tdap and influenza vaccines during pregnancy was not associated with a higher risk of medically attended adverse acute outcomes or birth outcomes compared with sequential vaccination. LEVEL OF EVIDENCE: II

Demographic characteristics of members of the Vaccine Safety Datalink (VSD): A comparison with the United States population.

BACKGROUND The Vaccine Safety Datalink (VSD) is a collaboration between CDC and nine integrated health care systems that serves as a cornerstone of US post-licensure vaccine safety monitoring. Given concerns that potential differences between the insured VSD population and the US population could limit the generalizability of VSD study findings, we performed a comparison of the demographic characteristics between the two populations. METHODS We collected data from medical records and administrative files at VSD sites in 2010 to compare sex, age, race, ethnicity, income, and educational attainment to the 2010 US Census population. We also compared data on the 2012 VSD Medicaid population to 2012 US Medicaid data. RESULTS The VSD population included over eight million individuals in 2010, which represented 2.6% of the total US population. All major demographic groups were represented in the VSD. We found no major differences in comparing sex, race, ethnicity, and educational attainment between the VSD and the US population. Middle income populations were comparable between the VSD and the US. While the percentage of lower income populations was less in the VSD compared to the US, the VSD had over two million individuals in this group. Additionally, there were over 600,000 Medicaid members in the VSD in 2012, which represented 1.1% of the US Medicaid population. CONCLUSIONS We found that the VSD population is representative of the general US population on several key demographic and socioeconomic variables. Despite a few specific groups being underrepresented in the VSD compared to the US, the absolute number of VSD members is large enough to ensure significant representation of these groups in vaccine safety studies that use VSD data.

Quadrivalent HPV vaccine safety review and safety monitoring plans for nine-valent HPV vaccine in the United States

ABSTRACT Quadrivalent human papillomavirus (4vHPV) vaccine was licensed for use in the United States in 2006 and through 2015 was the predominate HPV vaccine used. With the exception of syncope, a known preventable adverse event after any injected vaccination, both pre-licensure and post-licensure 4vHPV safety data have been reassuring with no confirmed safety signals identified. Nine-valent HPV vaccine (9vHPV) was licensed in 2014. This review includes post-licensure 4vHPV safety findings published to date that have informed the US vaccination program; these data will inform US safety monitoring and evaluation for 9vHPV.

Risk of Preterm or Small-for-Gestational-Age Birth After Influenza Vaccination During Pregnancy: Caveats When Conducting Retrospective Observational Studies

Vaccines are increasingly targeted toward women of reproductive age, and vaccines to prevent influenza and pertussis are recommended during pregnancy. Prelicensure clinical trials typically have not included pregnant women, and when they are included, trials cannot detect rare events. Thus, postmarketing vaccine safety assessments are necessary. However, analysis of observational data requires detailed assessment of potential biases. Using data from 8 Vaccine Safety Datalink sites in the United States, we analyzed the association of monovalent H1N1 influenza vaccine (MIV) during pregnancy with preterm birth (<37 weeks) and small-for-gestational-age birth (birth weight < 10th percentile). The cohort included 46,549 pregnancies during 2009-2010 (40% of participants received the MIV). We found potential biases in the vaccine-birth outcome association that might occur due to variable access to vaccines, the time-dependent nature of exposure to vaccination within pregnancy (immortal time bias), and confounding from baseline differences between vaccinated and unvaccinated women. We found a strong protective effect of vaccination on preterm birth (relative risk = 0.79, 95% confidence interval: 0.74, 0.85) when we ignored potential biases and no effect when accounted for them (relative risk = 0.91; 95% confidence interval: 0.83, 1.0). In contrast, we found no important biases in the association of MIV with small-for-gestational-age birth. Investigators conducting studies to evaluate birth outcomes after maternal vaccination should use statistical approaches to minimize potential biases.

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.

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.

Neonatal infections: case definition and guidelines for data collection, analysis, and presentation of immunisation safety data.

Maternal vaccination is an important area of research and requires appropriate and internationally comparable definitions and safety standards. The GAIA group, part of the Brighton Collaboration was created with the mandate of proposing standardised definitions applicable to maternal vaccine research. This study proposes international definitions for neonatal infections. The neonatal infections GAIA working group performed a literature review using Medline, EMBASE and the Cochrane collaboration and collected definitions in use in neonatal and public health networks. The common criteria derived from the extensive search formed the basis for a consensus process that resulted in three separate definitions for neonatal blood stream infections (BSI), meningitis and lower respiratory tract infections (LRTI). For each definition three levels of evidence are proposed to ensure the applicability of the definitions to different settings. Recommendations about data collection, analysis and presentation are presented and harmonized with the Brighton Collaboration and GAIA format and other existing international standards for study reporting.

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.