Safety profile of rotavirus vaccines among individuals aged ≥8 months of age, United States, vaccine adverse event reporting system (VAERS), 2006-2019.

INTRODUCTION: In 2006 and 2008, two live, oral rotavirus vaccines, RotaTeq (RV5) and Rotarix (RV1), were introduced into the routine immunization program in the United States. A previous rotavirus vaccine, RotaShield, was associated with an increased risk of intussusception, with data suggesting an age-dependent variation in risk. Advisory Committee on Immunization Practices (ACIP) currently recommends that RV5 or RV1 immunization be initiated by age 14 weeks and 6 days and completed by 8 months 0 days. METHODS: We searched for U.S. VAERS reports of RV5, RV1, or unknown rotavirus vaccine brand among individuals aged ≥8 months. We analyzed reports by 2 age groups (individuals aged ≥8 months-≤5 years and ≥6 years), vaccine brand name, adverse event (AE) reported, classification of seriousness (death, non-death serious, and non-serious) and mode of exposure (direct vs. indirect exposure). For serious reports we reviewed available medical records and assigned a primary diagnosis. RESULTS: VAERS received a total of 344 U.S. reports following rotavirus vaccination among individuals ≥8 months of age, 32 (9.3%) were serious. In the younger age-group, 307 (99%) of 309 reports followed direct vaccination of the child. In contrast, in individuals aged ≥6 years, 21 (60%) of 35 reports were via potential indirect exposure to a vaccinated child. The frequently reported AEs in the younger age-group were inappropriate schedule of drug administration 104 (34%) and drug administered to patient of inappropriate age 45 (15%); in the older group these were accidental exposure 9 (26%) and eye irritation 7 (20%). No difference in the safety profile was observed between RV1 and RV5. CONCLUSIONS: We did not identify any unexpected AEs for RV vaccines among individuals aged ≥8 months. Health care providers should adhere to the ACIP recommended schedule and older individuals should apply necessary precautions to prevent potential secondary exposure from vaccinated children.

Prevention of Hepatitis A Virus Infection in the United States: Recommendations of the Advisory Committee on Immunization Practices, 2020.

HEPATITIS A IS A VACCINE-PREVENTABLE, COMMUNICABLE DISEASE OF THE LIVER CAUSED BY THE HEPATITIS A VIRUS (HAV). THE INFECTION IS TRANSMITTED VIA THE FECAL-ORAL ROUTE, USUALLY FROM DIRECT PERSON-TO-PERSON CONTACT OR CONSUMPTION OF CONTAMINATED FOOD OR WATER. HEPATITIS A IS AN ACUTE, SELF-LIMITED DISEASE THAT DOES NOT RESULT IN CHRONIC INFECTION. HAV ANTIBODIES (IMMUNOGLOBULIN G [IGG] ANTI-HAV) PRODUCED IN RESPONSE TO HAV INFECTION PERSIST FOR LIFE AND PROTECT AGAINST REINFECTION; IGG ANTI-HAV PRODUCED AFTER VACCINATION CONFER LONG-TERM IMMUNITY. THIS REPORT SUPPLANTS AND SUMMARIZES PREVIOUSLY PUBLISHED RECOMMENDATIONS FROM THE ADVISORY COMMITTEE ON IMMUNIZATION PRACTICES (ACIP) REGARDING THE PREVENTION OF HAV INFECTION IN THE UNITED STATES. ACIP RECOMMENDS ROUTINE VACCINATION OF CHILDREN AGED 12-23 MONTHS AND CATCH-UP VACCINATION FOR CHILDREN AND ADOLESCENTS AGED 2-18 YEARS WHO HAVE NOT PREVIOUSLY RECEIVED HEPATITIS A (HEPA) VACCINE AT ANY AGE. ACIP RECOMMENDS HEPA VACCINATION FOR ADULTS AT RISK FOR HAV INFECTION OR SEVERE DISEASE FROM HAV INFECTION AND FOR ADULTS REQUESTING PROTECTION AGAINST HAV WITHOUT ACKNOWLEDGMENT OF A RISK FACTOR. THESE RECOMMENDATIONS ALSO PROVIDE GUIDANCE FOR VACCINATION BEFORE TRAVEL, FOR POSTEXPOSURE PROPHYLAXIS, IN SETTINGS PROVIDING SERVICES TO ADULTS, AND DURING OUTBREAKS.

Safety review of tetanus toxoid, reduced diphtheria toxoid, acellular pertussis vaccines (Tdap) in adults aged ≥65 years, Vaccine Adverse Event reporting System (VAERS), United States, September 2010-December 2018.

INTRODUCTION: The Advisory Committee on Immunization Practices (ACIP) recommends vaccination with tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine (Tdap) in persons ≥65 years of age. To date, few studies have assessed the safety of Tdap in this population. We aimed to summarize reports submitted to the Vaccine Adverse Event Reporting System (VAERS) following receipt of Tdap in this age group. METHODS: We searched for and analyzed U.S. VAERS reports of Tdap among individuals ≥65 years of age submitted from September 1, 2010 through December 31, 2018. We classified reports according to concurrent vaccination, seriousness, and outcome (death, non-death) and determined the frequency of reported adverse events (AEs). For serious reports, we reviewed available medical records. Data mining analyses were undertaken to detect disproportionality in reporting. RESULTS: VAERS received a total of 1,798 reports following Tdap, of which 104 (6%) were serious. The most common AEs were injection site erythema (26%; n = 468), injection site pain (19%; n = 335), injection site swelling (18%; n = 329), and erythema (18%; n = 321). We identified seven deaths; none were attributed to Tdap. Among serious non-death reports, nervous system disorders (35.1%; n = 34) and infections and infestations (n = 18.6%; n = 18) were most commonly reported. Data mining did not identify any vaccine-AE combination reported more frequently than expected. CONCLUSIONS: We did not identify any new safety concern over nearly a decade of recommended Tdap use among adults ≥65 years of age. Findings from this post-marketing review are consistent with prior post-marketing observations and pre-licensure studies.

Erythema multiforme, Stevens Johnson syndrome, and toxic epidermal necrolysis reported after vaccination, 1999-2017.

BACKGROUND: Since the last review of vaccine safety surveillance data for erythema multiforme (EM), Stevens Johnson syndrome (SJS), SJS/TEN, and toxic epidermal necrolysis (TEN) (EM/SJS/TEN), over 37 new vaccines have been introduced in the United States. We sought to describe reported EM/SJS/TEN after vaccines during 1999-2017. METHODS: We identified U.S. reports of EM/SJS/TEN received by the Vaccine Adverse Event Reporting System (VAERS) during 1999-2017. We stratified analysis by condition (EM, SJS, or TEN), and analyzed reports by serious or non-serious status, sex, age group, time from vaccination to symptom onset, exposure to known causes of EM/SJS/TEN, and vaccines administered. We used Empirical Bayesian data mining to detect vaccine-AE pairs reported more frequently than expected. RESULTS: Of 466,027 reports to VAERS during 1999-2017, we identified 984 reports of EM, 89 reports of SJS, 6 reports of SJS/TEN, and 7 reports of TEN. Few reports of EM (9%), and most reports of SJS (52%), SJS/TEN (100%), and TEN (100%) were serious. Overall, 55% of reports described males, 48% described children aged < 4 years; 58% of EM/SJS/TEN occurred ≤ 7 days after vaccination. Few reports (≤5%) described exposure to known causes of EM/SJS/TEN. Overall, childhood vaccines (e.g., combined measles, mumps, and rubella vaccine) were most commonly reported. We identified 6 deaths; 4 were exposed to medications associated with EM/SJS/TEN. EM after smallpox vaccine was reported disproportionately among people aged 19-49 years. CONCLUSIONS: EM/SJS/TEN were rarely reported after vaccination; data mining identified a known association between EM and smallpox vaccine.

Challenges in evaluating post-licensure vaccine safety: observations from the Centers for Disease Control and Prevention.

Introduction: Vaccination is one of the most successful and cost-effective public health interventions. Although vaccines undergo extensive safety and efficacy evaluations prior to licensure, vaccine safety assessment post-licensure is essential for detecting rare and longer-term adverse events (AEs) and maintaining public confidence in vaccines and recommended immunization programs. Despite the proven effect of vaccines to save lives and prevent disease and overwhelming evidence of vaccines' safety and societal benefit, like any drug, no vaccine can be considered as completely safe and completely effective. New vaccines continue to be introduced and require rapid safety assessment post-licensure through pharmacovigilance reports as well as epidemiologic studies to investigate any potential safety signals.Areas covered: We discuss selected challenges for conducting pharmacovigilance and epidemiologic studies of AEs after vaccination in the United States using the post-licensure safety surveillance infrastructure of the Centers for Disease Control and Prevention (CDC).Expert opinion: The availability of specific post-licensure surveillance systems to monitor and study AEs after vaccination, such as the Vaccine Adverse Event Reporting System, the Vaccine Safety Datalink, and the Clinical Immunization Safety Assessment Project, each with its unique set of strengths and limitations, provide a harmonized and supportive approach to meet several of these barriers.

Post-licensure surveillance of trivalent adjuvanted influenza vaccine (aIIV3; Fluad), Vaccine Adverse Event Reporting System (VAERS), United States, July 2016-June 2018.

BACKGROUND: Trivalent adjuvanted influenza vaccine (aIIV3; Fluad®) was approved in the United States (U.S.) in 2015 for adults aged ≥65 years and has been in use since the 2016-17 influenza season. METHODS: We analyzed U.S. reports for aIIV3 submitted from July 1, 2016 through June 30, 2018 to the Vaccine Adverse Event Reporting System (VAERS), a national spontaneous reporting system. Medical records were reviewed for serious reports. Among individuals ≥65 years of age, the relative frequency of the most commonly reported adverse events (AEs) after aIIV3 were compared with non-adjuvanted inactivated influenza vaccines given to adults aged ≥65 years, high-dose trivalent influenza vaccine (IIV3-HD) and trivalent or quadrivalent vaccines (IIV3/IIV4). Data mining analyses were undertaken to identify whether AEs for aIIV3 occurred disproportionately more than expected compared to all influenza vaccines. RESULTS: VAERS received 630 reports after aIIV3, of which 521 (83%) were in adults aged ≥65 years; 79 (13%) in persons <65 years and in 30 (5%) reports age was missing; 19 (3%) reports were serious, including two deaths (0.4%) related to myocardial infarction and Sjogren's syndrome. The most common AEs reported in adults aged ≥65 years were injection site pain (21%) and erythema (18%), with similar proportions reported for IIV3-HD (17% and 19%, respectively) and for IIV3/IIV4 (15%, each). Except for reports related to vaccination of inappropriate age (n = 79) and syringe malfunction (n = 6), data mining did not identify other disproportionately reported AEs. CONCLUSIONS: Although our review of aIIV3 in VAERS did not identify any unexpected health conditions of concern, we observed more than twice the expected number of reports with administration of the vaccine to persons outside of the age range for which the vaccine is approved in the U.S. Health care providers should be educated on the age groups for whom aIIV3 is recommended.

Reports of lower respiratory tract infection following dose 1 of RotaTeq and Rotarix vaccines to the Vaccine Adverse Event Reporting System (VAERS), 2008-2016.

A 2018 manufacturer post-licensure safety study identified a possible association between Rotarix (RV1) rotavirus vaccine and lower respiratory tract infections (LRTI) in infants within 0-6 days following receipt of RV1 dose 1. We reviewed reports to the Vaccine Adverse Event Reporting System (VAERS) of LRTI occurring 0-6 days and 0-29 days post vaccination following RotaTeq (RV5) or Rotarix (RV1) vaccinations in conjunction with either Prevnar (PCV7) or Prevnar 13 (PCV13), in infants aged 6 to 15 weeks. There was no significant difference in LRTI reports to VAERS in the 0-6 days and 0-29 days following receipt of either RV5 or RV1 given with either pneumococcal vaccine.

Prevention of Hepatitis B Virus Infection in the United States: Recommendations of the Advisory Committee on Immunization Practices.

HEPATITIS B VIRUS (HBV) IS TRANSMITTED VIA BLOOD OR SEXUAL CONTACT. PERSONS WITH CHRONIC HBV INFECTION ARE AT INCREASED RISK FOR CIRRHOSIS AND LIVER CANCER AND REQUIRE MEDICAL CARE. THIS REPORT UPDATES AND SUMMARIZES PREVIOUSLY PUBLISHED RECOMMENDATIONS FROM THE ADVISORY COMMITTEE ON IMMUNIZATION PRACTICES (ACIP) AND CDC REGARDING THE PREVENTION OF HBV INFECTION IN THE UNITED STATES. ACIP RECOMMENDS TESTING ALL PREGNANT WOMEN FOR HEPATITIS B SURFACE ANTIGEN (HBSAG), AND TESTING HBSAG-POSITIVE PREGNANT WOMEN FOR HEPATITIS B VIRUS DEOXYRIBONUCLEIC ACID (HBV DNA); ADMINISTRATION OF HEPB VACCINE AND HEPATITIS B IMMUNE GLOBULIN (HBIG) FOR INFANTS BORN TO HBV-INFECTED WOMEN WITHIN 12 HOURS OF BIRTH, FOLLOWED BY COMPLETION OF THE VACCINE SERIES AND POSTVACCINATION SEROLOGIC TESTING; UNIVERSAL HEPATITIS B VACCINATION WITHIN 24 HOURS OF BIRTH, FOLLOWED BY COMPLETION OF THE VACCINE SERIES; AND VACCINATION OF CHILDREN AND ADOLESCENTS AGED <19 YEARS WHO HAVE NOT BEEN VACCINATED PREVIOUSLY. ACIP RECOMMENDS VACCINATION OF ADULTS AT RISK FOR HBV INFECTION, INCLUDING UNIVERSAL VACCINATION OF ADULTS IN SETTINGS IN WHICH A HIGH PROPORTION HAVE RISK FACTORS FOR HBV INFECTION AND VACCINATION OF ADULTS REQUESTING PROTECTION FROM HBV WITHOUT ACKNOWLEDGMENT OF A SPECIFIC RISK FACTOR. THESE RECOMMENDATIONS ALSO PROVIDE CDC GUIDANCE FOR POSTEXPOSURE PROPHYLAXIS FOLLOWING OCCUPATIONAL AND OTHER EXPOSURES. THIS REPORT ALSO BRIEFLY SUMMARIZES PREVIOUSLY PUBLISHED AMERICAN ASSOCIATION FOR THE STUDY OF LIVER DISEASEST GUIDELINES FOR MATERNAL ANTIVIRAL THERAPY TO REDUCE PERINATAL HBV TRANSMISSION.

Safety of currently licensed hepatitis B surface antigen vaccines in the United States, Vaccine Adverse Event Reporting System (VAERS), 2005-2015.

INTRODUCTION: Currently four recombinant hepatitis B (HepB) vaccines are in use in the United States. HepB vaccines are recommended for infants, children and adults. We assessed adverse events (AEs) following HepB vaccines reported to the Vaccine Adverse Event Reporting System (VAERS), a national spontaneous reporting system. METHODS: We searched VAERS for reports of AEs following single antigen HepB vaccine and HepB-containing vaccines (either given alone or with other vaccines), from January 2005 - December 2015. We conducted descriptive analyses and performed empirical Bayesian data mining to assess disproportionate reporting. We reviewed serious reports including reports of special interest. RESULTS: VAERS received 20,231 reports following HepB or HepB-containing vaccines: 10,291 (51%) in persons <2 years of age; 2588 (13%) in persons 2-18 years and 5867 (29%) in persons >18 years; for 1485 (7.3%) age was missing. Dizziness and nausea (8.4% each) were the most frequently reported AEs following a single antigen HepB vaccine: fever (23%) and injection site erythema (11%) were most frequent following Hep-containing vaccines. Of the 4444 (22%) reports after single antigen HepB vaccine, 303 (6.8%) were serious, including 45 deaths. Most commonly reported cause of death was Sudden Infant Death Syndrome (197). Most common non-death serious reports following single antigen HepB vaccines among infants aged <1 month, were nervous system disorders (15) among children aged 1-23 months; infections and infestation (8) among persons age 2-18 years blood and lymphatic systemic disorders; and general disorders and administration site conditions among persons age >18 years. Most common vaccination error following single antigen HepB was incorrect product storage. CONCLUSIONS: Review current U.S.-licensed HepB vaccines administered alone or in combination with other vaccines did not reveal new or unexpected safety concerns. Vaccination errors were identified which indicate the need for training and education of providers on HepB vaccine indications and recommendations.

Safety of Second-Dose Single-Antigen Varicella Vaccine.

BACKGROUND AND OBJECTIVE: In 2006, routine 2-dose varicella vaccination for children was recommended to improve control of varicella. We assessed the safety of second-dose varicella vaccination. METHODS: We identified second-dose single-antigen varicella vaccine reports in the Vaccine Adverse Event Reporting System during 2006 to 2014 among children aged 4 to 18 years. We analyzed reports by age group (4-6 and 7-18 years), sex, serious or nonserious status, most common adverse events (AEs), and whether other vaccines were administered concomitantly with varicella vaccine. We reviewed serious reports of selected AEs and conducted empirical Bayesian data mining to detect disproportional reporting of AEs. RESULTS: We identified 14 641 Vaccine Adverse Event Reporting System reports after second-dose varicella vaccination, with 494 (3%) classified as serious. Among nonserious reports, injection site reactions were most common (48% of children aged 4-6 years, 38% of children aged 7-18 years). The most common AEs among serious reports were pyrexia (31%) for children aged 4 to 6 years and headache (28%) and vomiting (27%) for children aged 7 to 18 years. Serious reports of selected AEs included anaphylaxis (83), meningitis (5), encephalitis (16), cellulitis (52), varicella (6), herpes zoster (6), and deaths (7). One immunosuppressed adolescent was reported with vaccine-strain herpes zoster. Only previously known AEs were reported more frequently after second-dose varicella vaccination compared with other vaccines. CONCLUSIONS: We identified no new or unexpected safety concerns for second-dose varicella vaccination. Robust safety monitoring remains an important component of the national varicella vaccination program.

Post-licensure surveillance of 13-valent pneumococcal conjugate vaccine (PCV13) in adults aged ⩾19years old in the United States, Vaccine Adverse Event Reporting System (VAERS), June 1, 2012-December 31, 2015.

BACKGROUND: The 13-valent pneumococcal conjugate vaccine (PCV13) was first recommended for use in adults aged ⩾19years with immunocompromising conditions in June 2012. On August 2014, the Advisory Committee on Immunization Practices (ACIP) recommended routine use of PCV13 among adults aged ⩾65years. METHODS: We assessed adverse events (AEs) reports following PCV13 in adults aged ⩾19years reported to the Vaccine Adverse Event Reporting System (VAERS) from June 2012 to December 2015. VAERS is a national spontaneous reporting system for monitoring AEs following vaccination. Our assessment included automated data analysis, clinical review of all serious reports and reports of special interest. We conducted empirical Bayesian data mining to assess for disproportionate reporting. RESULTS: VAERS received 2976 US PCV13 adult reports; 2103 (71%) of these reports were from PCV13 administered alone. Fourteen percent were in persons aged 19-64years and 86% were in persons aged ⩾65years. Injection site erythema (28%), injection site pain (24%) and fever (22%) were the most frequent AEs among persons aged 19-64years; injection site erythema (30%), erythema (20%) and injection site swelling (18%) were the most frequent among persons aged ⩾65years who were given the vaccine alone. The most frequently reported AEs among non-death serious reports were injection site reactions and general malaise among persons 19-64years old; injection site reactions, general malaise and Guillain-Barré syndrome among those ⩾65years (Table 2). Data mining did not detect disproportional reporting for any unexpected AE. CONCLUSIONS: The results of this study were consistent with safety data from pre-licensure studies of PCV13. We did not detect any new or unexpected AEs.

Surveillance systems and methods for monitoring the post-marketing safety of influenza vaccines at the Centers for Disease Control and Prevention.

INTRODUCTION: Annual influenza vaccine safety monitoring is an important component of the influenza vaccination program in the United States to ensure that vaccines are safe, which is important for maintaining public trust in the national vaccination program. This is specially the case for influenza vaccines since the antigen composition of the viruses of which the vaccine is made often changes from one season to the next, based on the circulating strain of influenza virus. AREAS COVERED: This review describes the two surveillance systems used by the Centers for Disease Control and Prevention (CDC) to monitor the safety of influenza vaccines: 1) the Vaccine Adverse Event Reporting System (VAERS); and 2) the Vaccine Safety datalink (VSD). EXPERT OPINION: VAERS and VSD are used routinely to monitor the safety of influenza vaccines in the United States, and over the years they have demonstrated their value in monitoring vaccine safety since their implementation in 1990. Both systems, although different, complemented each other well to study febrile seizures in young children following influenza vaccination during the 2010-2011 influenza season. Other examples of potential safety concerns after influenza vaccines are also presented and discussed.

Post-licensure surveillance of quadrivalent inactivated influenza (IIV4) vaccine in the United States, Vaccine Adverse Event Reporting System (VAERS), July 1, 2013-May 31, 2015.

BACKGROUND: Quadrivalent inactivated influenza vaccines (IIV4) were first available for use during 2013-14 influenza season for individuals aged ≥6 months. IIV4 is designed to protect against four different flu viruses; two influenza A viruses and two influenza B viruses. METHODS: We searched the Vaccine Adverse Event Reporting System (VAERS) for US reports after IIV4 and trivalent inactivated influenza vaccine (IIV3) from 7/1/2013-5/31/2015. Medical records were requested for non-manufacturer reports classified as serious (i.e. death, hospitalization, prolonged hospitalization, life-threatening illness, permanent disability). The review included automated data analysis, clinical review of all serious reports, reports of special interest, and empirical Bayesian data mining. RESULTS: VAERS received 1,838 IIV4 reports; 512 (28%) in persons aged 6 months-17 years of which 42 (8.2%) were serious reports; 1,265 (69%) in persons aged >18 years of which 84 (6.6%) were serious reports; two in children <6 months and 59 in persons of unknown age. Injection site erythema (24%), fever (14%) and injection site swelling (17%) were the most frequent adverse events among persons aged 6 months-17 years, while injection site pain (16%), pain (15%) and pain in extremity (13%) were the most frequent among persons aged 18-64 years given the vaccine alone. Among non-death serious reports, injection site reactions, constitutional symptoms, Guillain-Barré syndrome, seizures, and anaphylaxis were the most frequently reported adverse events. Data mining detected disproportional reporting for incorrect vaccine administration with no associated adverse events. Adverse events following IIV4 reported to VAERS were similar to those following IIV3. CONCLUSIONS: In our review of VAERS reports, IIV4 had a similar safety profile to IIV3. Most of the reported AEs were non-serious. Our findings are consistent with data from pre-licensure studies of IIV4.

Post-Licensure Surveillance of Trivalent Live-Attenuated Influenza Vaccine in Children Aged 2-18 Years, Vaccine Adverse Event Reporting System, United States, July 2005-June 2012.

BACKGROUND: The first trivalent live-attenuated influenza vaccine (LAIV3) was licensed in 2003 for use in healthy persons 5-49 years of age. In 2007, the US Food and Drug Administration expanded its indication to healthy children 2-4 years of age. METHODS: We searched the Vaccine Adverse Event Reporting System (VAERS) for US reports after LAIV3 from July 1, 2005 to June 30, 2012 in children aged 2-18 years. Medical records were requested for nonmanufacturer reports coded as serious (ie, death, hospitalization, prolonged hospitalization, life-threatening illness, disability). We characterized electronic data and clinically reviewed all serious reports and reports of special interest. Empirical Bayesian data mining was used to identify new or unexpected adverse events (AEs). RESULTS: During the study period, VAERS received 2619 US LAIV3 reports for children aged 2-18 years; 197 (7.5%) reports were serious, including 5 deaths. The 2 most frequent nonfatal serious reports involved neurological and respiratory systems, with 56 (29.2%) and 43 (22.4%) reports, respectively. The most frequent neurological diagnoses were seizures and Guillain-Barré Syndrome, and the most frequent respiratory conditions were pneumonia and asthma or reactive airway disease. Data mining showed increased proportions for reports of medication errors, most commonly vaccine administration errors not associated with an AE. CONCLUSIONS: In this VAERS analysis of reports following LAIV3, we found no new or unexpected AEs patterns. Reports of LAIV3 administration to persons, for whom it is not recommended, including children with a history of asthma or reactive airway disease or wheezing, indicate that ongoing monitoring and education in vaccine indications are needed.

Intussusception after monovalent rotavirus vaccine-United States, Vaccine Adverse Event Reporting System (VAERS), 2008-2014.

BACKGROUND: In 2006 and 2008, two new rotavirus vaccines (RotaTeq [RV5] and Rotarix [RV1]) were introduced in the United States. US data on intussusception have been mostly related to RV5, with limited data on RV1. METHODS: We assessed intussusception events following RV1 reported to the Vaccine Adverse Event Reporting System (VAERS), a US national passive surveillance system, during February 2008-December 2014. We conducted a self-controlled risk interval analysis using Poisson regression to estimate the daily reporting ratio (DRR) of intussusception after the first 2 doses of RV1 comparing average daily reports 3-6 versus 0-2 days after vaccination. We calculated the excess risk of intussusception per 100,000 vaccinations based on DRRs and background rates of intussusception. Sensitivity analyses were conducted to assess effects of differential reporting completeness and inaccuracy of baseline rates. RESULTS: VAERS received 108 confirmed insusceptible reports after RV1. A significant clustering was observed on days 3-8 after does1 (p=0.001) and days 2-7 after dose 2 (p=0.001). The DRR comparing the 3-6 day and the 0-2 day periods after RV1 dose 1 was 7.5 (95% CI=2.3, 24.6), translating to an excess risk of 1.6 (95% CI=0.3, 5.8) per 100,000 vaccinations. The DRR was elevated but not significant after dose 2 (2.4 [95% CI=0.8,7.5]). The excess risk ranged from 1.2 to 2.8 per 100,000 in sensitivity analysis. CONCLUSIONS: We observed a significant increased risk of intussusception 3-6 days after dose 1 of RV1. The estimated small number of intussusception cases attributable to RV1 is outweighed by the benefits of rotavirus vaccination.

Post-licensure surveillance of quadrivalent live attenuated influenza vaccine United States, Vaccine Adverse Event Reporting System (VAERS), July 2013-June 2014.

BACKGROUND: Quadrivalent live attenuated influenza vaccine (LAIV4) was approved in 2012 for healthy persons aged 2-49 years. Beginning with the 2013-2014 influenza season, LAIV4 replaced trivalent live attenuated influenza vaccine (LAIV3). METHODS: We analyzed LAIV4 reports to VAERS, a national spontaneous reporting system. LAIV4 reports in 2013-2014 were compared to LAIV3 reports from the previous three influenza seasons. Medical records were reviewed for non-manufacturer serious reports (i.e., death, hospitalization, prolonged hospitalization, life-threatening illness, permanent disability) and reports of selected conditions of interest. We conducted Empirical Bayesian data mining to identify disproportional reporting for LAIV4. RESULTS: In 2013-2014, 12.7 million doses of LAIV4 were distributed and VAERS received 779 reports in individuals aged 2-49 years; 95% were non-serious. Expired drug administered (42%), fever (13%) and cough (8%) were most commonly reported in children aged 2-17 years when LAIV4 was administered alone, while headache (18%), expired drug administered (15%) and exposure during pregnancy (12%) were most common in adults aged 18-49 years. We identified one death report in a child who died from complications of cerebellar vascular tumors. Among non-death serious reports, neurologic conditions were common in children and adults. In children, seizures (3) and Guillain-Barré syndrome (2) were the most common serious neurologic outcomes. We identified three serious reports of asthma/wheezing following LAIV4 in children. Data mining detected disproportional reporting for vaccine administration errors and for influenza illness in children. CONCLUSIONS: Our analysis of VAERS reports for LAIV4 did not identify any concerning patterns. The data mining finding for reports of influenza illness is consistent with low LAIV4 vaccine effectiveness observed for influenza A disease in children in 2013-2014. Reports of LAIV4 administration to persons in whom the vaccine is not recommended (e.g., pregnant women) indicate the need for education, training and screening regarding indications.

Post-licensure surveillance of trivalent live attenuated influenza vaccine in adults, United States, Vaccine Adverse Event Reporting System (VAERS), July 2005-June 2013.

BACKGROUND: Trivalent live attenuated influenza vaccine (LAIV3) was licensed and recommended for use in 2003 in children and adults 2-49 years of age. Post-licensure safety data have been limited, particularly in adults. METHODS: We searched Vaccine Adverse Event Reporting System (VAERS) for US reports after LAIV3 from July 1, 2005-June 30, 2013 (eight influenza seasons) in adults aged ≥ 18 years old. We conducted descriptive analyses and clinically reviewed serious reports (i.e., death, life-threatening illness, hospitalization, prolonged hospitalization, or permanent disability) and reports of selected conditions of interest. We used empirical Bayesian data mining to identify adverse events (AEs) that were reported more frequently than expected. We calculated crude AE reporting rates to VAERS by influenza season. RESULTS: During the study period, VAERS received 1207 LAIV3 reports in adults aged 18-49 years old; 107 (8.9%) were serious, including four death reports. The most commonly reported events were expired drug administered (n=207, 17%), headache (n=192, 16%), and fever (n=133, 11%). The most common diagnostic categories for non-fatal serious reports were neurological (n=40, 39%), cardiovascular (n=14, 14%), and other non-infectious conditions (n=20, 19%). We noted a higher proportion of Guillain-Barré syndrome (GBS) and cardiovascular reports in the Department of Defense (DoD) population compared to the civilian population. Data mining detected disproportional reporting of ataxia (n=15); clinical review revealed that ataxia was a component of diverse clinical entities including GBS. CONCLUSIONS: Review of VAERS reports are reassuring, the only unexpected safety concern for LAIV3 identified was a higher than expected number of GBS reports in the DoD population, which is being investigated. Reports of administration of expired LAIV3 represent administration errors and indicate the need for education, training and screening regarding the approved indications.

Notes from the field: reports of expired live attenuated influenza vaccine being administered--United States, 2007-2014.

Annual influenza vaccination is recommended for all persons aged ≥6 months. Two vaccine types are approved in the United States, injectable inactivated influenza vaccine (IIV) and live attenuated influenza vaccine (LAIV), which is administered intranasally. Influenza vaccine typicaly becomes widely available beginning in late summer or early fall. IIV has a standard expiration date of June 30 for any given influenza season (July 1 through June 30 of the following year). In contrast, after release for distribution, LAIV generally has an 18-week shelf life (Christopher Ambrose, MedImmune, personal communication, 2014). Because of its relatively short shelf life, LAIV might be more likely than IIV to be administered after its expiration date. To assess that hypothesis, CDC analyzed reports to the Vaccine Adverse Event Reporting System (VAERS) of expired LAIV administered during July 1, 2007, through June 30, 2014.

Intussusception following rotavirus vaccination: an updated review of the available evidence.

In 1999, the first rotavirus vaccine licensed in the USA was withdrawn 9 months after introduction due to an association with intussusception that was detected in post-licensure surveillance. This association prompted large clinical trials designed to ensure the safety of two current live oral rotavirus vaccines, RotaTeq and Rotarix, which have since been recommended for use worldwide. Following their introduction, post-licensure studies have focused not only on the effectiveness and impact of these vaccines, but also on continued surveillance for intussusception. Most recent evidence from several countries shows a small increased risk of intussusception following vaccination with Rotarix and RotaTeq within the context of their demonstrated benefits. This review summarizes the available data on the safety of rotavirus vaccines with regards to intussusception.