Report of a SPEAC webinar 22 september 2023: Sensorineural hearing loss, lassa virus disease and vaccines.

Lassa virus (LASV) belongs to the Arenavirus family. LASV is endemic in several West Africa countries and causes viral hemorrhagic fevers. The Nigeria CDC has reported that an outbreak in 2024 in 28 states has resulted in 7767 suspected cases of Lassa fever, 971 confirmed cases and 166 confirmed deaths up to 11 August.

Assessing vaccine safety during a pandemic: Recent experience and lessons learned for the future.

During the roll out of vaccines during a pandemic, questions regarding vaccine safety often arise. This was surely true during the SARS-CoV-2 pandemic. Different tools and capabilities exist during the pre-authorization phase and post introduction each with its strengths and limitations.

The critical role of background rates of possible adverse events in the assessment of COVID-19 vaccine safety.

Beginning in December of 2019, a novel coronavirus, SARS-CoV-2, emerged in China and is now a global pandemic with extensive morbidity and mortality. With the emergence of this threat, an unprecedented effort to develop vaccines against this virus began. As vaccines are now being introduced globally, we face the prospect of millions of people being vaccinated with multiple types of vaccines many of which use new vaccine platforms.

Consensus summary report for CEPI/BC March 12-13, 2020 meeting: Assessment of risk of disease enhancement with COVID-19 vaccines.

A novel coronavirus (CoV), Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in late 2019 in Wuhan, China and has since spread as a global pandemic. Safe and effective vaccines are thus urgently needed to reduce the significant morbidity and mortality of Coronavirus Disease 2019 (COVID-19) disease and ease the major economic impact. There has been an unprecedented rapid response by vaccine developers with now over one hundred vaccine candidates in development and at least six having reached clinical trials.

Analysis of safety data in children after receiving two doses of ProQuad® (MMRV).

Background: In randomized clinical studies, over 11,800 children, 12 months to 6 years of age, were administered ProQuad(®), a combination measles, mumps, rubella, and varicella vaccine (MMRV). This paper describes the safety following a 2-dose regimen of MMRV administered to children in the second year of life.

Methods: Safety data from five clinical studies were combined for all children who were scheduled to receive two doses of MMRV ∼3-6 months apart.

Meningococcal disease from the public health policy perspective.

The incidence and serogroup distribution of meningococcal disease vary by country and over time. In the United States, the annual incidence has been 0.5-1.

Paralytic syndromes in children: epidemiology and relationship to vaccination.

Acute flaccid paralysis is a standard outcome for detection of poliomyelitis globally and an ongoing potential vaccine-associated adverse event concern for polio, influenza, and meningococcal vaccines. No systematic population-based data on the epidemiologic and clinical features of this condition, or its potential association with immunization, have been reported from the United States. The present retrospective cohort study of acute flaccid paralysis in the Southern and Northern California Kaiser Permanente Health Care Plans was conducted using computerized diagnosis data and medical record review of potential cases among children aged 1 month to <15 years and diagnosed from January 1, 1992 through December 31, 1998.

Human papilloma virus immunization in adolescent and young adults: a cohort study to illustrate what events might be mistaken for adverse reactions.

Background: The large-scale implementation of human papilloma virus (HPV) immunization will be followed by cases of autoimmune diseases occurring in temporal association with immunizations. To anticipate events that might be mistakenly assumed to be caused by immunization, their prevalence was monitored before vaccine introduction.

Method: Cohort study carried out within a database of female adolescents (n = 214,896) and young adults (n = 221,472) followed in the pre-HPV vaccine era (2005), computing rates of emergency consultations, hospitalizations and outpatient consultations, and estimation of risks of coincident associations.

Comparison of the safety and immunogenicity of a refrigerator-stable versus a frozen formulation of ProQuad (measles, mumps, rubella, and varicella virus vaccine live).

Objective: A refrigerator-stable formulation of ProQuad has been developed to expand the utility of ProQuad to areas in which maintenance of a frozen cold chain (-15 degrees C or colder) during storage and transport may not be feasible. The objective of this study was to demonstrate that the immunogenicity and safety profiles of a refrigerator-stable formulation of ProQuad are similar to the recently licensed frozen formulation.

Methods: In this double-blind, randomized, multicenter study, healthy 12- to 23-month-old children with negative vaccination and clinical histories for measles, mumps, rubella, varicella, and zoster were vaccinated with either the refrigerator-stable formulation of ProQuad (N = 1006) or the frozen formulation of ProQuad (N = 513).

Hepatitis B vaccine and risk of autoimmune thyroid disease: a Vaccine Safety Datalink study.

Purpose: Hepatitis B vaccine has been postulated as a possible cause of autoimmune disorders, including autoimmune thyroid diseases (ATD). Cases of Graves' disease and Hashimoto's thyroiditis, following hepatitis B vaccine have been reported to the Vaccine Adverse Events Reporting System (VAERS). To test the hypothesis that hepatitis B vaccine increases the risk of ATD, we conducted a case-control study, within the Vaccine Safety Datalink project.

Safety of trivalent inactivated influenza vaccine in children 6 to 23 months old.

Context: Beginning with the winter season of 2004-2005, influenza vaccination has been recommended for all children 6 to 23 months old in the United States. However, its safety in young children has not been adequately studied in large populations.

Objective: To screen for medically attended events in the clinic, emergency department, or hospital after administration of trivalent inactivated influenza vaccine in children 6 to 23 months old.

Cost-effectiveness of pneumococcal conjugate vaccine: evidence from the first 5 years of use in the United States incorporating herd effects.

Background: Pneumococcal conjugate vaccine (PCV) has been in routine use in the United States for 5 years. Prior U.S.

Immunogenicity and safety of measles-mumps-rubella, varicella and Haemophilus influenzae type b vaccines administered concurrently with a fourth dose of heptavalent pneumococcal conjugate vaccine compared with the vaccines administered without heptavalent pneumococcal conjugate vaccine.

Background: Prevnar [heptavalent pneumococcal conjugate vaccine (PCV7)] is licensed in the United States for routine administration in infants and may be coadministered with other infant vaccines. Safety and immunogenicity data on the coadministration of the fourth dose of PCV7 with measles-mumps-rubella (MMR), varicella and Haemophilus influenzae type b (Hib) vaccines are limited.

Methods: Children 12-15 months of age received either MMR with PCV7 (group 1) or MMR without PCV7 (group 2).

Safety and efficacy of a pentavalent human-bovine (WC3) reassortant rotavirus vaccine.

Background: Rotavirus is a leading cause of childhood gastroenteritis and death worldwide.

Methods: We studied healthy infants approximately 6 to 12 weeks old who were randomly assigned to receive three oral doses of live pentavalent human-bovine (WC3 strain) reassortant rotavirus vaccine containing human serotypes G1, G2, G3, G4, and P[8] or placebo at 4-to-10-week intervals in a blinded fashion. Active surveillance was used to identify subjects with serious adverse and other events.

Compliance with national immunization guidelines for children younger than 2 years, 1996-1999.

Objectives: To evaluate compliance with national immunization guidelines among a large cohort of children cared for at health maintenance organizations (HMOs) and to examine effects on immunization status.

Methods: A cohort study of 176134 children born between January 1, 1994, and December 31, 1997, and monitored from birth to the second birthday was performed. Subjects belonged to the Vaccine Safety Datalink Project, a study of children enrolled in 1 of 4 HMOs.

Safety of the trivalent inactivated influenza vaccine among children: a population-based study.

Background: To our knowledge, there are no published population-based studies on the safety of the inactivated trivalent influenza vaccine among children.

Objective: To screen a large population of children for evidence of increased medical visits in the 2 weeks after influenza vaccination compared with 2 control periods. Secondary analyses included shorter risk periods and restricted age categories.

Safety, efficacy, and effectiveness of live, attenuated, cold-adapted influenza vaccine in an indicated population aged 5-49 years.

Background: Three important studies have supported licensure of live, attenuated, cold-adapted influenza vaccine (CAIV-T [FluMist; MedImmune Vaccines]): (1) a pediatric efficacy trial involving children 15-71 months of age, (2) a large safety study of medically attended events occurring among children 1-17 years of age, and (3) an effectiveness trial involving healthy working adults 18-64 years of age.

Methods: During the United States Food and Drug Administration (FDA) review for the approval of CAIV-T for use in healthy persons, additional subgroup analyses were conducted to evaluate the safety, efficacy, and effectiveness of the vaccine, by use of various age subsets not prespecified by the original protocols. CAIV-T is currently approved by the FDA for use in healthy persons 5-49 years of age.

Effectiveness of influenza vaccine during pregnancy in preventing hospitalizations and outpatient visits for respiratory illness in pregnant women and their infants.

The Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention recommends influenza vaccination for women who will be in the second or third trimester of pregnancy during the influenza season. We analyzed hospital admissions with principal diagnoses of influenza or pneumonia and influenza-like illness (ILI) outpatient visits to study the effectiveness of influenza vaccine during pregnancy in protecting women and infants from influenza-related morbidity. Estimates of influenza vaccine effectiveness across five flu seasons (Fall 1997 to Spring 2002) were calculated using Cox proportional hazards models for women and infant study populations in Kaiser Permanente Northern California.

Safety of thimerosal-containing vaccines: a two-phased study of computerized health maintenance organization databases.

Objective: To assess the possible toxicity of thimerosal-containing vaccines (TCVs) among infants.

Methods: A 2-phased retrospective cohort study was conducted using computerized health maintenance organization (HMO) databases. Phase I screened for associations between neurodevelopmental disorders and thimerosal exposure among 124 170 infants who were born during 1992 to 1999 at 2 HMOs (A and B).

Risk of anaphylaxis after vaccination of children and adolescents.

Objective: To quantify the risk of anaphylaxis after vaccination of children and adolescents.

Methods: The study population consisted of children and adolescents who were enrolled at 4 health maintenance organizations that participated in the Vaccine Safety Datalink Project. For the period 1991-1997, we identified potential cases by searching for occurrences of International Classification of Diseases, Ninth Revision (ICD-9) code 995.

A retrospective cohort study of the association of varicella vaccine failure with asthma, steroid use, age at vaccination, and measles-mumps-rubella vaccination.

Objective: Varicella breakthrough, the occurrence of varicella disease >42 days after vaccination, is indicative of vaccination failure. A sevenfold increased risk of breakthrough among vaccinated children with asthma was observed in a 1996 varicella outbreak in a child care center. More recent outbreak investigations have also identified age at vaccination as a potential risk factor for breakthrough.

Vaccinations and risk of central nervous system demyelinating diseases in adults.

Background: Several case reports of the onset or exacerbation of multiple sclerosis or other demyelinating conditions shortly after vaccination have suggested that vaccines may increase the risk of demyelinating diseases.

Objective: To evaluate the association between vaccination and onset of multiple sclerosis or optic neuritis.

Design: Case-control study involving cases of multiple sclerosis or optic neuritis among adults 18 to 49 years of age.

Polio extraimmunization in children younger than 2 years after changes in immunization recommendations.

Objective: To investigate trends over time in polio extraimmunization among children in 4 large health maintenance organizations and to study the association with recent changes in polio immunization policy.

Methods: Using 176 169 children who were born after 1994 and enrolled for their first 2 years of life, we assessed rates and trends of polio extraimmunization in the Vaccine Safety Datalink project. We used logistic regression to test the association of extraimmunization with different polio immunization schedules and with sociodemographic characteristics and used Poisson regression to test changes in rates over time.

Impact of the pneumococcal conjugate vaccine on otitis media.

Context: The heptavalent pneumococcal conjugate vaccine (PCV) is recommended for infants to protect against invasive disease, but its impact on otitis might also have public health importance.

Objective: To examine the impact of PCV on the incidence of otitis media, frequent otitis media and tympanostomy tube procedures and to assess whether the effectiveness of the vaccine wanes after age 24 months and varies by race, sex or season.

Design, Setting And Patients: From 1995 to 1998, 37 868 children at Kaiser Permanente in Northern California were randomized to receive PCV or a control vaccine in a double blind trial and were followed through April 1999.

Hepatitis B vaccination among adolescents in 3 large health maintenance organizations.

Objective: In 1995, the Advisory Committee on Immunization Practices (ACIP) recommended routine hepatitis B (HB) vaccination of all unvaccinated 11- to 12-year-old adolescents. Little is known about the implementation of these recommendations in a managed care setting. The objective of this study was to determine the impact of ACIP recommendations on HB vaccination among adolescents in 3 managed care settings.